Advances in rehabilitation for chronic diseases: improving health outcomes and functionBMJ 2019; 365 doi: https://doi.org/10.1136/bmj.l2191 (Published 17 June 2019) Cite this as: BMJ 2019;365:l2191
- Caroline R Richardson, professor of family medicine1,
- Barry Franklin, professor of physiology2,
- Marilyn L Moy, associate professor of medicine3,
- Elizabeth A Jackson, professor of medicine4
- 1Department of Family Medicine, University of Michigan, Ann Arbor, MI 48104, USA
- 2Oakland University William Beaumont, School of Medicine, Rochester, MI, USA
- 3Harvard Medical School, Boston, MA, USA
- 4University of Alabama, Birmingham, AL, USA
- Correspondence to: C R Richardson
Much of the burden on healthcare systems is related to the management of chronic conditions such as cardiovascular disease and chronic obstructive pulmonary disease. Although conventional outpatient cardiopulmonary rehabilitation programs significantly decrease morbidity and mortality and improve function and health related quality of life for people with chronic diseases, rehabilitation programs are underused. Barriers to enrollment are multifactorial and include failure to recommend and refer patients to these services; poor communication with patients about potential benefits; and patient factors including logistical and financial barriers, comorbidities, and competing demands that make participation in facility based programs difficult. Recent advances in rehabilitation programs that involve remotely delivered technology could help deliver services to more people who might benefit. Problems with intensity, adherence, and safety of home based programs have been investigated in recent clinical trials, and larger dissemination and implementation trials are under way. This review summarizes the evidence for benefit of in-person cardiac and pulmonary rehabilitation programs. It also reviews the literature on newer developments, such as home based remotely mediated exercise programs developed to decrease cost and improve accessibility, high intensity interval training in cardiac rehabilitation, and alternative therapies such as tai chi and yoga for people with chronic obstructive pulmonary disease.
Chronic conditions such as cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) are caused by poor health behaviors such as a sedentary lifestyle, an unhealthy diet, and cigarette smoking.1 Patients with these common chronic conditions are high utilizers of medical services,2 have a reduced health related quality of life,3 experience functional limitations,45 and are at risk of premature death.6 Conventional medical treatments are rarely effective in modifying behavioral risk factors.7 Medical research has focused mainly on developing new drugs to manage these chronic conditions,8910 and effective evidence based strategies to change the underlying poor health behaviors are underused.11121314 Despite advances in the medical management of CVD, ischemic heart disease remains the leading cause of death worldwide, and COPD recently became the third most common.15
A rehabilitation model, focused on forestalling the progression of chronic diseases before debilitating symptoms or life threating events occur,16 with specific emphasis on the subsets of the population that are disproportionately affected,17 offers a viable strategy to improve health outcomes. With this model, self management and support from evidence based interventions aimed at changing behavior will become more important.18 For people with chronic conditions, rehabilitation services focused on changing exercise, diet, and health behavior improve function,19 decrease symptoms,19 enhance health related quality of life,19202122 decrease future use of healthcare,202223 and may reduce mortality.202324
Primary care providers have an important role to play in expanding the use of cardiopulmonary rehabilitation for patients with CVD and COPD because they often manage patients after hospital admission for myocardial infarctions and COPD exacerbations. They are often responsible for ensuring that patients are referred to rehabilitation services, and that patients understand that such programs are safe and appropriate and that participation can greatly improve patient centered outcomes. Primary care providers face logistical barriers that limit the use of cardiopulmonary rehabilitation including competing demands, limited time, lack of training, and lack of logistical support, but certain evidence based system level strategies can improve the likelihood of participation.2526 Patient level barriers to participation include limited program availability, the inconvenience of attending classes several times a week, poor motivation, transport problems, competing work related or caregiving responsibilities, and cost including deductibles and co-pays.27 Newer models of home based and remotely mediated exercise programs may help overcome some of these barriers.28 Helping patients improve health outcomes by combatting chronic diseases with cardiopulmonary rehabilitation will help facilitate the transition from the current reactive sick care model to proactive healthcare.
This review summarizes randomized controlled trials (RCTs), meta-analyses, epidemiologic reports, and clinical and observational studies evaluating the impact of cardiopulmonary rehabilitation on CVD and COPD, with additional information about new developments and ongoing clinical trials.
Sources and selection criteria
Our reference search was broad and interdisciplinary in scope, and it covered biomedical, health, engineering, and computing fields. It included the following databases: PubMed, MEDLINE, EMBASE, ClinicalTrials.gov, the Cochrane Library, IEEE Xplore, and the ACM Digital Library. Title-abstract and full text keywords, MeSH terms, and controlled vocabulary were used to identify peer reviewed studies and reviews as well as in-progress research with preliminary results in the fields of computing and engineering. Our search was limited to the years 2008-18. Key terms were inclusively grouped and combined, including: “cardiovascular disease*”,“heart failure”, “chronic obstructive lung disease”, “chronic bronchitis”, “emphysema”, “pulmonary disease, chronic obstructive”, “chronic obstructive pulmonary disease", “pulmonary”, “rehabilitation”, “rehab*”, “telerehabilitation”, “physical activity”, “exercise therapy”, “home based”, “telemedicine”, “telehealth”, “mobile app*”, “web app*,” “mHealth”, “eHealth”, “text message”, “video*”, “videoconferencing”, “mobile phone”, “telecommunication*” (the asterisks are truncation symbols that allow for variations in word endings). In addition, we hand searched references in key articles for additional citations and included ongoing research in key computing and engineering journals, primarily published as conference proceedings with preliminary results using novel health technologies as well as alternative and integrative therapies.
We reviewed the identified manuscripts for their focus on elements of cardiac and pulmonary rehabilitation that were relevant to primary care physicians. We operationalized “relevant to primary care” as focusing on evidence of benefit of rehabilitation; appropriate referral criteria and referral strategies; and new and emerging developments in the delivery of rehabilitation including eHealth. Selection criteria targeted large clinical trials and major guidelines updates, excluding smaller clinical trials and pilot studies.
Cardiovascular disease and cardiac rehabilitation
What is cardiac rehabilitation?
Conventional facility based cardiac rehabilitation covers 10 domains of cardiac risk factor modification (fig 1). A supervised exercise program with gradually progressive and individually tailored exercise goals is generally considered the cornerstone of cardiac rehabilitation but the other nine components play a crucial role in further reducing risk factors and increasing the probability of long term adherence to lifestyle changes.29
Benefits of rehabilitation in cardiovascular disease (table 1)
In patients with known CVD, a systematic review and meta-analysis found that participation in a cardiac rehabilitation program reduced cardiovascular mortality (27 trials, relative risk 0.74, 95% confidence interval 0.64 to 0.86) but not overall mortality (47 trials, 0.96, 0.88 to 1.05) compared with a no exercise control group. In addition, participation in cardiac rehabilitation reduced the rate of hospital readmission (15 trials, 0.82, 0.70 to 0.96) but not the rates of myocardial infarction, percutaneous coronary intervention (PCI), or coronary artery bypass grafting (CABG).20 Higher volume cardiac rehabilitation programs defined as those with ≥36 sessions and medium volume programs defined as those with 12-35 sessions were more effective at lowering all cause mortality than programs with fewer than 12 sessions.30
Much of the research has focused on the exercise component of cardiac rehabilitation, with a meta-analysis showing that people who participate in a program increase their structured exercise significantly more than those who do not participate,32 and that such interventions are cost effective.31 A 2013 international consensus statement that focused on recommendations for choice of workload intensity in cardiac rehabilitation generally favored higher intensity over light to moderate intensity workloads to maximize benefit.33 Choice of intensity is tailored to the individual patient’s pathophysiology and clinical status and is usually based on an objective functional evaluation through exercise testing.
Research on high intensity interval training (HIIT) in which participants alternate brief high intensity exercise bouts with periods of recovery throughout the exercise session suggests that HIIT is more effective at increasing cardiorespiratory fitness and improving indices of vascular function, including brachial artery flow mediated dilatation (endothelial function)34 than moderate intensity continuous exercise. A meta-analysis of 10 RCTs concluded that HIIT is superior to continuous exercise training in improving aerobic capacity in patients with coronary heart disease (CHD) (+1.78 mL/kg/min, 0.45 to 3.11) although participants randomized to the continuous exercise arm lost slightly more weight (−0.48 kg, 0.15 to 0.81) and had a larger reduction in mean resting heart rate. There is concern that HIIT exercise may transiently increase the risk of adverse coronary events but trials that are large enough and long enough to assess the associated risk accurately have not been completed.35 In addition, although HIIT offers a time saving alternative to moderate intensity continuous training, in previously inactive, unfit middle aged and older participants, pleasure seems to decrease as the intensity of exercise increases,36 which may negatively influence long term compliance.
Comprehensive cardiovascular rehabilitation includes non-exercise interventions that cover smoking cessation, psychosocial problems, stress, adherence to prescribed drugs, and diet (fig 1). In a study of 4673 patients with a new diagnosis of coronary artery disease in the past year, those who stopped smoking after their first adverse cardiovascular event had a lower risk of recurrent events (adjusted hazard ratio 0.66, 0.49 to 0.88) and of all cause mortality (0.63, 0.48 to 0.82) than those who continued smoking.37 A recent systematic review of psychological interventions for patients with CVD concluded that although the evidence is generally of low quality, such interventions may reduce the risk of cardiovascular mortality (relative risk 0.79, 0.63 to 0.98), but not total mortality, and improve symptoms of depression, stress, and anxiety, particularly for people with previously diagnosed psychological disorders.38
Cardiac rehabilitation referral and enrollment
Most patients who attend conventional cardiac rehabilitation programs are referred on discharge from a hospital stay for acute coronary syndrome, systolic heart failure, PCI, valvular surgery, or CABG. Referral rates for cardiovascular rehabilitation at hospital discharge have increased over the past decade with the increasing emphasis on referral as a performance measure. However, the increase in referral rates has not translated into an increase in participation rates.39 Currently, in the United States only about half of cardiac patients are referred for rehabilitation.3940 About 35% of patients with a history of an acute myocardial infarction report having attended a cardiac rehabilitation program, a rate that has been relatively stable over the past 10 years.39 Women are less likely than men to be referred to or attend cardiac rehabilitation.12 In addition, participation is generally lower for patients who are black (odds ratio 0.70, 0.53 to 0.93), uninsured (0.53, 0.37 to 0.75), less educated (0.47, 0.37 to 0.61), or current smokers (0.76, 0.58 to 1.00).39
A large prospective observational study of referral strategies showed that combining an automated referral order with a liaison strategy in which a nurse or other provider discussed the referral with the patient before hospital discharge was significantly more effective than either strategy alone.41 Eligible and consented participants who were discharged from hospitals with the combined referral strategy had an 85.8% referral rate and a 73.5% enrollment rate. This combined strategy resulted in 13% higher enrollment than an automated order alone and 23% higher enrollment than liaison intervention alone. This trial was conducted in Canada and cardiac rehabilitation was covered for all study participants, which may have contributed to the high participation rates. A large RCT of a similar intervention aimed at increasing enrollment and participation in cardiac rehabilitation found that a clear written and oral explanation of the content and benefits of cardiac rehabilitation combined with a follow-up phone call two weeks after discharge almost doubled participation.25 Although not necessarily new, one of the most effective interventions to increase enrollment and participation in these programs is the strong recommendation of the patient’s primary care physician or cardiologist.26
Transition to primary care after cardiac rehabilitation
Transition of care is important at discharge from cardiac rehabilitation but communication between the rehabilitation unit and the primary care provider is often limited. A mixed methods study of 22 cardiac rehabilitation sites in Canada reported that only 42% of 50 primary care providers received a discharge summary from the program.42 Thus, details about the patient’s care were not known to the provider charged with maintaining continuity of care for the patient. Primary care physicians reported missing crucial information including details of the exercise prescription, dietary plan, medication list, and contact information for the staff involved in the patient’s care.42
Interventions that move cardiac rehabilitation out of the hospital and into the primary care or community setting may improve access to and participation in rehabilitation. In a study of a group based HIIT exercise class that was conducted twice a week in a primary care setting and supervised by an exercise physiologist, 87% of participants completed the 12 week program and showed a mean increase in cardiorespiratory fitness (VO2 max) of 4.1 ±3.2 mL/kg/min with no adverse exercise related cardiovascular events.43
eHealth cardiac rehabilitation
Digital health, which is rapidly being incorporated into healthcare, can reduce geographic barriers to cardiac rehabilitation.28 In the US, more than 90% of adults own a mobile phone, and more than 50% of these are smart phones.44 In one systematic review, digital health interventions were associated with a 40% reduction in cardiac events (relative risk 0.60, 0.43 to 0.83) among patients with documented CVD, compared with usual care.45
Several trials have shown that cardiac rehabilitation programs delivered by technology with remote sensor monitoring and telephone or internet based coaching can increase physical activity and yield similar outcomes when compared with conventional programs and that rates of adherence are significantly higher. The CardioFit study examined an internet based program in people who were recruited from the hospital and were not participating in traditional cardiac rehabilitation. Participants (n=223) were assigned to an internet program with personally tailored physical activity planning and tracking or to usual care, which did not include conventional cardiac rehabilitation but did include guidance on physical activity from an attending cardiologist. At 12 months, participants using the internet program were significantly more physically active as measured by both pedometers (average daily step difference 642 steps, group effect P=0.023) and self reported moderate to vigorous physical activity (min/week difference 32, group effect P=0.047) compared with usual care.46
An Australian RCT compared traditional facility based rehabilitation with a home cell phone mediated cardiac rehabilitation program in 120 patients with a recent myocardial infarction. The cell phone mediated intervention covered all core elements of a comprehensive cardiac rehabilitation program. It included cell phone delivered educational and motivational content, objective monitoring of physical activity through the cell phone’s accelerometer sensor, and manually entered weight and blood pressure measured by a standardized home scale and blood pressure monitor, as well as a brief weekly coaching phone call for six weeks. The remote cell phone based intervention had significantly higher rates of uptake (80% v 62%; relative risk 1.30, 1.03 to 1.64; P<0.05), adherence (94% v 68%; 1.4, 1.13 to 1.70; P<0.05), and completion (80% v 47%; 1.71, 1.30 to 2.27; P<0.05) than the traditional facility based rehabilitation program. Physiologic outcomes were similar because both groups showed significant improvements in six minute walk test (6MWT) from baseline to six weeks (traditional: mean 537 (standard deviation ±86) m to 584 (±99) m; cell phone: 510 (±77) m to 570 (±80) m), which was maintained at six months. This preliminary study suggests that a cell phone based remotely delivered program may be an effective alternative to conventional cardiac rehabilitation.47
The Heart Exercise and Remote Technologies (HEART) study randomized 171 patients with ischemic heart disease who were clinically stable either to a digital intervention that included personalized text messages and a secure website with videos or to usual care.48 All participants had access to a community based cardiac rehabilitation program that included the option of participating in a supervised exercise program. At 24 months, those randomized to the technology arm did not increase their peak oxygen consumption (difference=0.21 mL/kg/min, 1.1 to 0.7; P=0.65) but did report increases in leisure time physical activity (difference=110.2 min/week, 0.8 to 221.3; P=0.05) and walking (difference=151.4 min/week, 27.6 to 275.2; P=0.02) as well as improved self efficacy for physical activity (difference=6.2%, 0.2% to 12.2%; P=0.04). These results suggest that a technology mediated cardiac rehabilitation coaching and support program may increase leisure time physical activity, walking time, and quality of life in those with access to community based cardiac rehabilitation programs. These studies support the utility of further evaluation of eHealth in people undergoing cardiac rehabilitation. Data on long term efficacy and the impact on healthcare utilization are limited, and data on implementation are even more so.
Several ongoing studies may help provide answers to the efficacy, accuracy, acceptability, and costs of eHealth interventions for cardiac rehabilitation. Many pilot studies and large RCTs of mobile cardiac rehabilitation interventions are currently recruiting (table 2). The recent partnerships between leaders in the technology industry and cardiovascular societies such as the American Heart Association and the American College of Cardiology should help promote high quality research in this area.4950
Pre-habilitation before cardiac surgery
Although cardiac rehabilitation is usually initiated after a cardiac event, there is increasing interest in pre-habilitation or exercise based rehabilitation before cardiovascular surgery. In a pre-habilitation program evaluation that used historical controls and propensity matching, increased physical activity before surgery was associated with a shorter length of hospital stay (number in program 117, difference 2 days, P value not reported) and reduced hospital cost (difference $2308 (£1773; €2051); P value not reported).51 An observational study of 2172 patients (76% men, 24% women) admitted for acute coronary syndrome evaluated the effect of physical activity status before admission on mortality in hospital and cardiovascular health outcomes one month after discharge.52 After adjusting for age and sex, physically active patients had an odds ratio of 0.53 (0.03 to 0.93) of in-hospital mortality relative to inactive patients. The investigators concluded that a physically active lifestyle, structured exercise, or both could provide added cardioprotection and improve short term prognosis in hospital inpatients with acute cardiac syndromes. This prompted a series of prospective investigations of cardiopulmonary rehabilitation before hospital admission for cardiovascular surgery.
Until recently, studies that evaluated the impact of pre-habilitation in patients awaiting CABG have mostly been small pilot studies and rarely included a control condition. The initial outcomes reported in these preliminary studies suggest that pre-habilitation increases exercise tolerance, decreases length of hospital stay, reduces the incidence of pneumonia and duration of intubation, and improves quality of life after surgery.5354 A recent meta-analysis of eight trials, six of which were RCTs, found evidence of a reduction in postoperative complication rate (odds ratio 0.41, 0.28 to 0.62; P<0.001) and a significant increase in postoperative maximal inspiratory pressure (standard mean difference 0.66, 0.35 to 0.96; P<0.001). There was also a trend towards reduced length of stay but it was not statistically significant.55 Currently, five small randomized clinical trials listed on clinicaltrials.gov are recruiting patients to investigate the impact of pre-habilitation on patients preparing for cardiac surgery (fig 2).
Chronic obstructive pulmonary disease and pulmonary rehabilitation
COPD is a common preventable pulmonary disease that mostly represents lung damage caused by cigarette smoking. Chronic bronchitis and emphysema are components of the spectrum of this disease. COPD is a major cause of global morbidity and is currently the third leading cause of death worldwide.56 In 2015, 3.2 million people died from COPD worldwide,57 and the number of COPD related hospital admissions is expected to double by 2030, partly due to ageing of the population.58 About 6% of adults in the US have been diagnosed by a physician as having COPD,59 even though underdiagnosis and overdiagnosis of COPD are common. A recent population level spirometry screening program for people aged over 40 years in Ontario, Canada, found that 8.8% of the 1403 participants had been diagnosed as having COPD by a physician but that less than half of them were confirmed to have COPD by spirometry. An additional 13.7% who had not been previously diagnosed met criteria for COPD by spirometry, resulting in a population prevalence by spirometry of 17.4%. However, those who were asymptomatic with abnormal spirometry would not necessarily need any intervention other than counseling for smoking cessation.60
Improving the accuracy of diagnosis may be the crucial first step in providing guideline concordant care for patients with COPD including referral to pulmonary rehabilitation. The definition of COPD by spirometry according to the 2017 Global Initiative for Chronic Obstructive Lung Disease (GOLD)61 criteria is forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) <0.70. For those aged over 40 years with symptoms such as chronic cough, sputum production, dyspnea, or wheezing and a history of smoking or secondhand smoke exposure, spirometry screening for COPD is recommended to make a definitive diagnosis.
The GOLD criteria further assign stages 1-4 for severity of airflow limitation on the basis of FEV1% of predicted (mild: >80%; moderate: 50-80%; severe: 30-50%; and very severe: <30%). In addition, the GOLD criteria can be used to stratify patients by risk using the assessment of symptoms and number of recent exacerbations (fig 3). Symptoms can be assessed using criteria from the modified British Medical Research Council (MRC) Questionnaire62 by asking whether symptoms are at the level (or worse than) that described in the following sentence: “I walk slower than people of the same age on the level because of breathlessness, or I have to stop for breath when walking at my own pace on the level.” GOLD guidelines recommend pulmonary rehabilitation for patients with high levels of symptoms and for those in risk categories B, C, or D.
All cigarette smokers, regardless of COPD diagnosis or spirometry profile, have the potential to benefit from counseling, medication, and behavioral support for smoking cessation.63 Effective interventions for smoking cessation have been administered in hospital inpatients, in outpatient primary care settings, through quit phone lines, on websites that provide support for quitting, and in conventional pulmonary rehabilitation programs. Smoking cessation is the only intervention that has been shown to stop the progression of COPD in patients who smoke. The number needed to treat to prevent one smoking related death with a smoking cessation program is estimated to be between 18 and 67, depending on quit rates without the intervention and on the quality of the intervention.64 A large pragmatic trial in US veterans who were current smokers and had been diagnosed as having COPD (n=648) showed that active telephone outreach offering smoking cessation treatment increased six month cessation rates from 8.7% to 13.1% (odds ratio 3.45, 1.59 to 7.47).65
Despite maximal medical therapy, patients with COPD characteristically experience breathlessness, which leads to a downward spiral of sedentary behavior, physical inactivity, muscle deconditioning, and functional disability.61666768 Even at the early stages of disease, people with COPD spend significantly longer being sedentary, and thus less time being physically active, compared with healthy people,6970 and COPD exacerbations accelerate the decline in physical activity.71 In addition, COPD is associated with age related comorbidities such as cardiovascular disease, diabetes, and osteoporosis—all of which further contribute to functional limitations.7273
Engagement in physical activity is a modifiable health behavior that affects COPD specific health outcomes independent of lung function.7374757677787980 People with COPD who have a high daily step count are at lower risk of dying than those with a low daily step count even after controlling for lung function (FEV1).747576 An observational cohort study of 169 people with COPD who wore an accelerometer showed that those who were the least physically active had double the risk of acute exacerbations and six times the risk of hospital admission over a median follow-up of 16 months compared with those who walked the most.77 Patients who reported any moderate to vigorous physical activity (MVPA) had a lower risk of 30-day hospital readmission after an index admission for COPD compared with those who reported no MVPA.78 These studies of daily step count support the notion that every step walked can positively affect COPD outcomes.
The GOLD guidelines recommend regular physical activity for all people with stable COPD as standard of care.61 The current standard of care to promote physical activity can be broadly separated into either exercise counseling or referral to conventional supervised pulmonary rehabilitation.81 Brief, episodic general advice to increase physical activity from a healthcare provider has limited success.82 By contrast, conventional supervised programs clearly reduce breathlessness and improve health related quality of life (HRQL) and exercise capacity.19 Although smoking cessation is crucial to prevent the onset or progression of COPD, participation in a comprehensive pulmonary rehabilitation program is a highly effective intervention for those who are living with COPD.
What is pulmonary rehabilitation?
Outpatient pulmonary rehabilitation programs typically consist of two to three sessions a week for 9-12 weeks. The main components of facility based supervised conventional pulmonary rehabilitation are aerobic exercise, strength training, and education.81 There is progression of aerobic exercise with use of treadmills, stationary upright or recumbent bicycles, and arm ergometers. Topics commonly taught in the education component include the management of dyspnea, the use of medications and oxygen, nutrition, the management of anxiety and depression, strategies for long term behavior change, smoking cessation, and the management of acute exacerbations (fig 4).83
Aerobic exercise is an important part of pulmonary rehabilitation. However, people who have COPD are often limited by dyspnea when participating in such exercise. For this reason, pulmonary rehabilitation is less likely to include high intensity aerobic training and more likely to use strategies that do not cause severe dyspnea.84 Resistance exercise, including exercises for strengthening both the upper and lower extremities, are included in most supervised pulmonary rehabilitation programs. A meta-analysis of neuromuscular stimulation training (NMST), which involves applying an electrical stimulus to small muscles to trigger contraction, has been used in pulmonary rehabilitation clinical trials with heterogeneous results. One meta-analysis of eight trials and 156 patients showed no benefit of NMST.85 Another meta-analysis of nine trials and 276 participants showed increased quadricep muscle strength (standardized mean difference (SMD)=1.12, 0.64 to 1.59; I2=54%; P<.01) and improvement in 6MWT distance (weighted mean difference (WMD)=37.27, 31.82 to 42.73; I2=0; P<.01) but no significant improvement in HRQL (by St George's Respiratory Questionnaire (SGRQ): WMD=−0.07, −2.44 to 2.30; I2=56%; P=0.95).86
Benefits of pulmonary rehabilitation in COPD
Conventional hospital based programs, with core components of aerobic exercise, strength training, education, and social support, clearly improve exercise capacity, decrease breathlessness, and improve HRQL in people with COPD. A 2015 systematic review and meta-analysis synthesized data from 65 RCTs, 41 of which were hospital based, 23 community based, and one with both a hospital and a community component. The authors found significant improvements in all health related quality of life domains assessed by the two mostly commonly used measures in patients with COPD—the Chronic Respiratory Questionnaire (CRQ) scores for dyspnea, fatigue, emotional function, and mastery and the SGRQ. Pulmonary rehabilitation also had a favorable impact on exercise capacity and functional measures. Both maximal exercise capacity (mean difference in maximum workload (Wmax) 6.77 W, 1.89 to 11.65) and 6MWT distance (mean difference 43.93 m, 32.64 to 55.21) increased more in the pulmonary rehabilitation arm than in the usual care arm, and these differences were all statistically significant. The authors of the systematic review concluded that there was such strong evidence for the benefit of pulmonary rehabilitation in health related quality of life that no further research was needed in this area.19
It is more difficult to demonstrate decreases in hospital readmissions and mortality. A 2016 systematic review of eight studies of pulmonary rehabilitation after hospital admission for a COPD exacerbation showed moderate quality evidence that pulmonary rehabilitation substantially reduced hospital readmissions (odds ratio 0.44, 0.21 to 0.91).22 A more recent meta-analysis included 10 RCTs and eight observational studies. Pooled results from the 10 RCTs showed a decrease in rates of readmission to hospital in those who were randomized to pulmonary rehabilitation (control groups: 0.97 hospital admissions/patient year, 0.67 to 1.40; pulmonary rehabilitation groups: 0.62 hospital admissions/patient year, 0.33 to 1.16), but the observational trials reported no benefit.87
In addition to readmission, the 2016 systematic review estimated the effect of pulmonary rehabilitation on mortality. Previous systematic reviews suggested a survival benefit for pulmonary rehabilitation, but with the addition of new trials with heterogeneous results the effect on mortality was no longer significant. Several recent observational cohort studies compare people with COPD referred to pulmonary rehabilitation in which about half completed the program. Those who completed pulmonary rehabilitation were more likely to survive than those who did not attend or did not complete the program.2488 However, this was not a randomized comparison and sicker patients may have simply been unable to tolerate the exercise therapy.
Pulmonary rehabilitation referral and enrollment
Despite strong evidence of efficacy, referral rates of people with COPD to pulmonary rehabilitation are generally low. However, a recent meta-analysis reported considerable variation in referral rates.89 In 28 observational studies, the referral rate ranged from 0% to 85%, with a median rate of 17%. Two significant outliers were seen among the 28 studies—an 85% referral rate in a practice that had implemented the Living Well with COPD program and just over a 60% referral rate in another practice. The other 26 studies had referral rates below 40%. Seven other studies reviewed in the same publication showed that median referrals increased 6.5% after interventions to improve COPD care.
One important barrier to participation may be that programs are available to only a small fraction of patients with COPD. The American Association of Cardiovascular and Pulmonary Rehabilitation website lists fewer than 600 certified programs in the US for the estimated 16 million Americans diagnosed with COPD. An analysis of more than 33 000 Medicare beneficiaries with COPD from 1 January 2003 to 31 December 2012 showed that only 1239 people (3.7%) used pulmonary rehabilitation in 2012, with a dismal 1.1% increase in use over the 10 years.90 There is geographic disparity in availability because most programs are located at tertiary care centers and require patients to travel to the program two or three times a week.293032 In the National Emphysema Treatment Trial, participants who lived more than 36 miles from the treatment facility were less likely to complete pulmonary rehabilitation. The wide variation in pulmonary rehabilitation referral rates suggests that targeted interventions and improvements in clinical processes could significantly affect referral rates. Many of those who enroll in pulmonary rehabilitation do not complete the program. Anticipated barriers to completing the program reported in one qualitative study included the perceived high intensity of the program, barriers to attending (such as transport problems, sudden illness, and other duties or responsibilities), a perceived lack of improvement, and social factors.27
Patients with COPD who are in hospital because of an exacerbation are often slow to recover, so an argument can be made to delay the start of pulmonary rehabilitation until after a recovery period of at least four weeks. However, recent evidence suggests that starting pulmonary rehabilitation within four weeks of an acute exacerbation and possibly even sooner while the patient is still in hospital may be more effective. A meta-analysis of trials that compared early pulmonary rehabilitation with either late or no pulmonary rehabilitation showed a substantial reduction in mortality (relative risk 0.58, 0.35 to 0.98) and hospital readmissions (0.47, 0.29 to 0.75).91 Starting pulmonary rehabilitation during the inpatient stay may also improve engagement and retention in pulmonary rehabilitation after discharge (table 3).
Exercise maintenance after pulmonary rehabilitation
There is no standardized intervention to maintain physical activity and the benefits of pulmonary rehabilitation after completion of the program.8193949596 The programs, which are typically nine to 12 weeks in duration, focus on short term increases in cardiorespiratory fitness and exercise capacity, and they do not consistently result in sustained increases in physical activity as assessed by community based walking.97 Only 41% of people described themselves as regular walkers in the year after they completed pulmonary rehabilitation.98 In the absence of a maintenance strategy, gains in exercise capacity and HRQL start to drop towards pre-intervention levels as early as three to six months after the program ends.8199
Home based, eHealth, and unsupervised pulmonary rehabilitation
As with cardiac rehabilitation, there is an emerging field of research into the development of a safe and effective home based pulmonary rehabilitation program. Using technology to deliver an exercise program to patients in their own homes increases access but may do so at the expense of delivering a “watered down” and less effective form of rehabilitation. A recent meta-analysis of 10 clinical trials that compared facility based and home based programs showed similar improvements in HRQL and exercise capacity.92 An additional clinical trial randomized 287 participants with COPD who were referred for pulmonary rehabilitation to either traditional facility based rehabilitation or a structured unsupervised home based exercise program with outpatient and telephone delivered behavioral counseling. After seven weeks, both groups significantly improved on the Chronic Respiratory Questionnaire Self-Report dyspnea domain, but those randomized to the facility based program improved slightly more, making the result of the non-inferiority trial inconclusive (mean group difference: −0.24, −0.61 to 0.12; P=0.18).100
Increasing physical activity and improving exercise capacity are two related, but distinct, goals in the management of COPD.75101 Exercise capacity is the amount of exercise patients are physically capable of doing, whereas physical activity reflects the intensity and duration of activity that patients perform in their everyday lives.102 Dyspnea leads to sedentary behavior and physical inactivity; muscle disuse leads to deconditioning and lower limb muscle dysfunction; and any further physical activity results in more dyspnea even in the absence of any deterioration in lung function.707398103 Traditionally, hospital based supervised pulmonary rehabilitation programs have focused on short term improvements in exercise capacity, as measured by performance tests like the 6MWT.81 However, the promotion of lifestyle and community based physical activity has emerged as an equally important goal in the care of patients with COPD.75102 Higher levels of physical activity, directly measured with pedometers and accelerometers, are associated with better outcomes in COPD—decreased risk of the use of accident and emergency facilities, hospital admission, and death—independent of lung function.7477 Getting patients to walk more to ameliorate existing or prevent further deconditioning prepares them to engage in higher intensity exercise training for future gains in exercise capacity. Increasing physical activity, by any amount and intensity, is the first step in a pathway to increasing aerobic fitness and exercise capacity in these patients. Interestingly, conventional pulmonary rehabilitation, which improves exercise capacity, does not always increase physical activity in the home setting.979899104105
Past efforts to develop home based pulmonary rehabilitation programs have generally shown home exercise to be safe but were limited by the need for frequent contact with staff and the inability to set measurable targets and accurately monitor the exercise performed.106107108 Interventions that use technology such as the internet and wearable devices have shown promise in supporting home based physical activity.109110111112113114 Most recently, tele-rehabilitation efforts used videoconferencing for home virtual supervision, but this still required personnel time and specialized exercise equipment.115116117118
Complementary and alternative approaches as adjuncts to pulmonary rehabilitation
Along with technology based interventions to deal with the problems of access and adherence to conventional pulmonary rehabilitation, the use of active mind-body movement therapies such as yoga,114119 tai chi,120121122123124 qi gong, and pilates has increased. Tai chi provides mild to moderate aerobic exercise corresponding to 1.6 to 4.6 metabolic equivalents, core strength training, and lower extremity and unsupported upper extremity training.122125126 Breathing retraining in COPD aims to teach patients to replace rapid shallow breathing patterns with slower deeper breathing patterns, which improves chest wall mechanics and diaphragm function, decreases dead space ventilation, and minimizes air trapping and dynamic hyperinflation. Increased awareness of posture and breathing improves participants’ ability to anticipate and manage their symptoms, decreasing the risk of precipitating a vicious cycle of breathlessness and anxiety. These modalities have been shown to be safe in patients with chronic heart failure, coronary artery disease (recovering from bypass surgery and myocardial infarction), frailty, arthritis, and vestibular disease.127 These activities can be performed at home, can be done seated, and may be enjoyable alternatives to walking or using exercise equipment.
Data on yoga and tai chi in COPD and pulmonary rehabilitation are limited.122 Meta-analyses of small studies have shown benefits in the 6MWT and HRQL in favor of tai chi (6MWT: meters difference 35.99, 15.63 to 56.35; P<0.01; HRQL: by SGRQ difference −10.02, −17.59 to −2.45; P=0.009 ) and yoga (6MWT: meters difference 22.01, 9.9 to 34.11; P<0.01; HRQL: by SGRQ difference −12.59, −18.49 to −.7; P<0. 01) when compared with usual care.119123 There are fewer studies of these modalities as adjuncts or as alternatives to pulmonary rehabilitation.114128 No data are available to support the use of tai chi or yoga as maintenance therapy after pulmonary rehabilitation, although some studies are under way.129 More data and well designed studies are needed. Both the active mind-body intervention and the comparator group (conventional pulmonary rehabilitation) need to be standardized. Most studies have been conducted in Chinese populations, and several studies are under way to test these interventions in Western populations to increase generalizability.113130
A search of ClinicalTrials.gov (CARDIAC REHABILITATION, and CURRENTLY RECRUITING, and ADULTS) finds 57 studies. Emerging research focuses on specialized patient populations, including those with heart failure and vascular disease, as well as frail patients. Additional trials are ongoing to clarify the role of technology in home based unsupervised exercise programs as well as the role of HIIT and NMES in cardiovascular rehabilitation (table 2).
In the Rehabilitation Therapy in Older Acute Heart Failure Patients (REHAB-HF), a total of 360 participants, aged 60 years or more, with acute decompensated heart failure will be randomized to an intervention starting with physical rehabilitation while in hospital and continuing for 12 weeks after discharge or to a control group that did not receive rehabilitation.131 Pilot data from 27 participants enrolled in REHAB-HF suggested that physical function was improved at three months and all cause readmission was reduced at six months in the rehabilitation group compared with usual care.132 An ongoing pilot study of home based exercise after transcatheter aortic valve replacement will examine physical function and disability, comparing baseline to eight weeks after surgery in 60 participants (≥65 years of age). The intervention starts within one week of discharge. The comparator group will receive an educational program (NCT02805309). An internet based exercise walking program for patients with peripheral arterial disease (PAD) is using a commercially available pedometer together with tailored step count goals and a PAD specific website for participants.133
In the RESTORE study, cardiovascular centers in Poland will enroll 1000 patients aged 70 years or less after hospital admission for acute coronary syndrome (ACS) who will have electrocardiography, heart rate, and blood pressure monitored remotely while cardiovascular rehabilitation is performed at home.134
Two other trials test novel interventions for cardiac rehabilitation. The Novel Strategies to Improve Cardiometabolic Status and Adherence to Exercise Regimens in Patients at High Risk for Cardiovascular Disease (BURST) trial will compare HIIT (10 minute sessions, three times a day, for five days a week) with traditional 30 minute bouts of moderate intensity exercise for changes in glycated hemoglobin, body mass index, and lipid profiles at three and 12 months (NCT03103854). The Building Strength Through Rehabilitation for Heart Failure Patients Study (BISTRO-STUDY) will enroll 60 participants recently admitted to hospital for heart failure who will be randomized to NMES versus a sham stimulation protocol to improve physical function, skeletal mass, and frailty measures at six to eight weeks and five to six months (NCT03615469).
Chronic obstructive pulmonary disease
A search of ClinicalTrials.gov (PULMONARY REHABILITATION, and COPD, and CURRENTLY RECRUITING, and ADULTS) finds 79 studies. Emerging research focuses on strategies for delivering pulmonary rehabilitation at home to increase access and adherence. Table 4 briefly describes seven large clinical trials currently recruiting participants. Three of the trials are testing strategies for home based pulmonary rehabilitation. In the REHABDO trial (NCT03453606), 670 patients will be allocated to facility based or home based rehabilitation. The allocation scheme is innovative in that those who express a strong preference for one setting or the other will be given their preference and those who do not express a strong preference will be randomly assigned. This trial design therefore considers patient preference, which may influence outcomes. Patients assigned to the home program will be offered weekly 1.5 hour sessions in their home for eight weeks. A second trial comparing home based and facility based pulmonary rehabilitation will randomize 200 patients to 12 weeks of a home based program supervised by a telephone based health coach or a traditional facility based program (NCT03480386). Another trial targets patients who have recently been discharged from hospital for a COPD exacerbation and again randomizes eligible participants to a home based exercise program with remote supervision or facility based rehabilitation. The primary goal of this trial is to reduce hospital readmissions (NCT03865329).
Advice on the appropriate referral of patients with CVD and COPD to rehabilitation programs can be found in guidelines that deal more generally with the appropriate care for patients with these chronic conditions. The box provides a list of current guidelines on referral to cardiovascular and pulmonary rehabilitation.
Guidelines for cardiac and pulmonary rehabilitation
Secondary prevention in the clinical management of patients with cardiovascular diseases. Core components, standards and outcome measures for referral and delivery: a policy statement from the cardiac rehabilitation section of the European Association for Cardiovascular Prevention and Rehabilitation. Endorsed by the committee for practice guidelines of the European Society of Cardiology
AACVPR/ACCF/AHA 2010 Update: performance measures on cardiac rehabilitation for referral to cardiac rehabilitation/secondary prevention services
Secondary prevention through cardiac rehabilitation: from knowledge to implementation. A position paper from the cardiac rehabilitation section of the European Association of Cardiovascular Prevention and Rehabilitation
Referral, enrollment, and delivery of cardiac rehabilitation/secondary prevention programs at clinical centers and beyond: a presidential advisory from the American Heart Association
2018 ACC/AHA Clinical performance and quality measures for cardiac rehabilitation: a report of the American College of Cardiology/American Heart Association task force on performance measures
GOLD Report 201761
Global strategy for the diagnosis, management and prevention of chronic obstructive lung disease 2017 report
An official American Thoracic Society/European Respiratory Society policy statement: enhancing implementation, use, and delivery of pulmonary rehabilitation
An official European Respiratory Society statement on physical activity in COPD
An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation
British Thoracic Society guideline on pulmonary rehabilitation in adults
Abbreviations: AACVPR=American Association of Cardiovascular and Pulmonary Rehabilitation; ACC= American College of Cardiology; ACCF=American College of Cardiology Foundation; AHA=American Heart Association; ATS=American Thoracic Society; BTS=British Thoracic Society; COPD=chronic obstructive pulmonary disease; EACPR=European Association for Cardiovascular Prevention and Rehabilitation; ESC= European Society of Cardiology; ERS=European Respiratory Society.
Cardiovascular rehabilitation referral guidelines
Guidelines recommend that patients who have been diagnosed with acute myocardial infarction, coronary artery surgery, heart failure, or angina within the past 12 months should be referred to cardiovascular rehabilitation. Some guidelines broaden these categories to include other patients at high risk, such as those with peripheral artery disease or those newly diagnosed with type 2 diabetes. Because many people with the most to gain from cardiac rehabilitation are not referred or do not attend within the first 12 months, some guidelines also recommend referral for those whose most recent cardiac event or diagnosis was longer than 12 months ago.135
Chronic obstructive pulmonary disease rehabilitation referral guidelines
Guidelines for the referral of patients with COPD to pulmonary rehabilitation recommend referral of those who are motivated, medically stable, and symptomatic with impairment in daily activities. Medically stable people include most of those who have recently been discharged from a hospital admission for a COPD exacerbation. Recent clinical guidelines recommend pulmonary rehabilitation for all patients with symptoms of COPD whose FEV1 is less than 50% predicted or for those with a FEV1 that is 50-70% of predicted133 who have had at least one hospital admission for an exacerbation or two or more exacerbations even if none resulted in hospital admission.61 Most pulmonary rehabilitation programs comprehensively evaluate referred patients to assess for safety, including assessing mobility and stability while using exercise equipment. Although symptomatic patients may have multiple comorbidities and have serious lung disease, because the benefits of pulmonary rehabilitation outweigh the risks, these patients should be referred.61
Chronic conditions such as CVD and COPD are caused by poor health behaviors including a sedentary lifestyle. Comprehensive cardiac and pulmonary rehabilitation programs are effective evidence based strategies that directly deal with the behavioral risk factors that lead to CVD and COPD, improving health related outcomes including function, HRQL, risk of readmission to hospital, and mortality. Unfortunately, only a small fraction of people who could benefit from cardiopulmonary rehabilitation participate. Thus, there is an opportunity to substantially improve health outcomes by increasing the reach and engagement of such programs. Primary care providers have a crucial role to play in realizing the full potential of rehabilitation strategies. Recent advances including system level strategies to improve referral rates, the development of eHealth remotely delivered home exercise programs, and evidence supporting benefits from alternative movement therapies such as tai chi have the potential to improve the efficacy and expand the reach of cardiopulmonary rehabilitation for patients with CVD and COPD.
Questions for future research
1 Apart from patients with traditional coronary artery disease, what other populations with cardiovascular disease would benefit from referral to cardiovascular rehabilitation?
2 How can primary care based, technology mediated, and home based components of cardiopulmonary rehabilitation be incorporated to optimize access and effectiveness?
3 Could new modes of exercise, such as high intensity interval training, be included as an option in cardiovascular rehabilitation to help improve outcomes?
4 Could neuromuscular electrical stimulation open up cardiovascular rehabilitation to patients who are too frail to participate in more traditional exercise programs?
5 Can safe and effective pulmonary rehabilitation be delivered to patients with chronic obstructive pulmonary disease at home as a way to increase access and participation rates?
6 Can technology mediated interventions enhance both short and long term adherence and maximize the benefits of pulmonary rehabilitation?
How patients were involved in the creation of this article
No patients were involved in the framing or writing of this review article.
We would like to thank Noa Kim for her expertise and assistance with literature searches, figure compliance, and reference accuracy.
Series explanation: State of the Art Reviews are commissioned on the basis of their relevance to academics and specialists in the US and internationally. For this reason they are written predominantly by US authors.
Contributors: CRR is the corresponding author and the guarantor and as such accepts full responsibility for the work and/or the conduct of the study, had access to the data, and controlled the decision to publish. All authors were involved in the initial scoping of the manuscript in collaboration with BMJ editors. CRR conducted the initial literature search with the help of Noa Kim an informationist who supports our research group. CRR also contributed expertise on eHealth and exercise-based rehabilitation. MLM contributed her expertise in COPD and pulmonary rehabilitation. BF and EAJ focused on the cardiology and cardiac rehabilitation sections of the manuscript, helping with literature interpretation as well as extensively revising the initial manuscript sections relevant to their areas of expertise.
Competing interests: The authors have read and understood BMJ policy on declaration of interests and have no competing interests to declare.
Provenance and peer review: Commissioned; externally peer reviewed.