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Rapid Responses: Rapid Responses published:
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Overall effect, of home monitoring on BP readings, is much greater in practice
- Julian D Povey (17 July 2004)
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Mercury in the domestic environment – a reflection of doctor behaviour?
- Phillip J. Colquitt (17 July 2004)
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Could it be concordance
- Andrew J Leigh (19 July 2004)
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Patients help to explain the benefits of home monitoring
- Andrew Herxheimer, Rachel Miller, Sue Ziebland (19 July 2004)
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Re: Patients help to explain the benefits of home monitoring
- Frankie E Campling (20 July 2004)
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Inconsequential meta-anaytical research
- David Barnes (21 July 2004)
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Home monitoring of Blood Pressure
- Mervyn S. Gotsman (21 July 2004)
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Systematic review guidelines’ acronym is QUOROM not QUORUM
- Willem J. Assendelft (23 July 2004)
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Meta-analysis does not allow appraisal of complex interventions
- Ingrid Mühlhauser (5 August 2004)
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Validity of conclusions
- Nick J Field (10 August 2004)
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Home monitoring of blood pressures could be useful for relevant few hypertensives
- Nasir Shariff (20 August 2004)
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Julian D Povey, GP principal Pontesbury Medical Practice, Pontesbury, Shropshire, SY5 0RF
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Nowadays, I seem to be looking more closer at patients who I feel have a degree of "White Coat Hypertension", by targetting these patients, and letting them record their own BP's prior to seeing me has resulted in substantially lower BP readings than those listed in the article. ALthough this article did not look at ambulatory home readings, I find that home self monitoring gives similar readings. Patients find home self monitoring easier, and I think are more likely to continue with their normal daily activities, compared to wearing a ambulatory monitor. The key benfit from the patients perspective, appears to be, that home monitoring rsults in less intensive medication. Competing interests: JP works a a GP under a nGMS contract, and reducing BP readings helps his Quality and Outcome framework payments |
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Phillip J. Colquitt, Technical Advisor Self-employed
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Despite the trend toward mercury substitution mentioned in this article, the trend to managing blood pressure at home, with the very best of intentions, together with the doctor inspired idea that mercury sphygs’ are best, may cause ordinary consumers of medical equipment to mimic the status of the doctor by buying a mercury sphyg’(the “gold” standard) for the home, even after a trial of electronic equipment. Is not there a need for the doctor himself to show the way by using non-mercury equipment? My observation is that there is only a slight increasing incidence in TV news segment “fillers” which show doctors using aneroid sphygs, but by far the media still prefer to show the doctor taking blood pressure with a mercury sphyg - the ratio is about 85/15 mercury/aneroid. At the same time, I note the proliferation of sales of medical equipment to the ever more aged and/or worried population, and these sales include mercury sphygs without hazard warning labels. Unregulated mercury from recycled medical and other equipment seems to find it’s way back into cheaper mercury sphygs coming from developing countries in Asia. I feel fairly sure that the domestic environment will become increasingly polluted with elemental mercury in the short to medium term, and that devices to detect the toxic vapours will become important in evaluation of property. Competing interests: None declared |
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Andrew J Leigh, Pharmacist Auckland, New Zealand
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In reading the above study it seems that it may only be a certain group of people that would be interested in home blood pressure reading. This group would tend to be those more interested in their disease and hence may be better at adhering to treatment for hypertension. Could this be responsible for the slight lowering of BP amongst this group? What may be fairer rather than a meta analysis of previous trials would be to test this hypothesis using data from the UK GP database or similar.This will at least show if these patients are picking up prescriptions more reliably than those not testing at home. There is of course those who pick up prescriptions but still don't take as prescribed. Competing interests: None declared |
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Andrew Herxheimer, co-founder, DIPEx project Dept of Primary Healthcare, University of Oxford, Oxford OX3 7LF, Rachel Miller, Sue Ziebland
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Carpuccio and colleagues found that home monitoring of blood pressure clearly contributes to better control, but remark that "the reasons for this are not clear". This is not surprising since randomised controlled trials themselves rarely help to explain their results. Narrative interviews of people with hypertension can however do so. Interviews of 18 such patients conducted in the UK in 2000 are summarised on the DIPEx (Database of Personal Experiences) website (www.dipex.org/hypertension); video or audio clips from the interviews illustrate the summary. Benefits of self-monitoring that patients mentioned included gaining reassurance, and understanding more about how the blood pressure fluctuates. It helped the patient to take responsibility for the condition, and to check if stress is affecting it. Home monitoring also made it much easier to cope with the the blood pressure, which could be very stressful precisely because it causes no symptoms. It can also convince the patient that the high blood pressure is real and that medication is necessary. This may be particularly important for patients who suspect that they may only have 'white coat hypertension' where the blood pressure is normal away from the doctor's surgery. The interviews also revealed people's doubts and hesitations about using a home blood pressure monitor. Some found the machines too expensive, or worried that the results may not be reliable, although those who had been able to check them against their practice machines had been reassured. Some of the people we saw suspected that their doctors and nurses disapproved of home monitors - one man had wondered about getting one but thought his doctor might laugh at him. We believe that self-monitoring leads to better control because it involves people much more in the management of their hypertension and motivates them to take part in it. The clear benefits identified by the meta-analysis now justify a general policy of encouraging and supporting home monitoring as part of the efforts to promote concordance. Competing interests: None declared |
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Frankie E Campling, medical author 88 LInkside Avenue, Oxford OX2 8JB
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I find that home monitoring of my blood pressure is useful. It helps me check what my BP is normally and discount the 'white coat syndrome', i.e. that my blood pressure is always raised in a medical setting. My G.P. approves. I take my monitor in with me and do my own reading after hers so that I can check that the pressure it records matches what my GP has taken. It certainly has helped me to discover the stresses that are likely to raise my BP. Frankie Campling Competing interests: None |
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David Barnes, semi-retired GP Home SG12 8RE
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The primary objection to these review efforts, by Cappuccio et al., of a multiplicity of work in metaänalytical form is fundamental. Objectivity and at least some validity are being sought now in this paper for parts of studies for which the designs were never originally undertaken; there is properly no natural indication for the aggregation of work done for many different purposes, by different people, over a range of time – here from 2 to 36 months but undertaken up to 25 years before. The hope no doubt is that the parts, even taken out of context, are in fact amalgamable, comparable and contrastable. Because of the degrees of uncertainty there is no conclusion which may be made with such reliability that it may be safely acted on. Forty years ago it was standard teaching that reports in the form of metaänalysis were worse than useless; there was always this risk that the implied and concluded findings would be acted on at face-value. Nothing has changed. In the work, the two objectives given are deceptively simple. What was the effect of home blood pressure monitoring on (1) (clinic) blood pressure levels and (2) on the proportion of people achieving set targets? In this paper we read of references to eighteen other papers chosen for review involving the 2417 people participating. All eighteen papers deal with the use of home or self-monitoring of essential hypertension with a (form of) sphygmomanometer. The comparability of all the targets is not established. The titles of the eighteen studies do reveal though the specific secondary objections to a tutti-frutti approach. The described purposes of the studies numbered 12 to 29 are in sequence as follows: the effects of self monitoring, medication compliance, none (for reference 14), family involvement, health education, effects on long term control, compliance techniques, none (for 19), services and costs, teaching, telecommunications and medication adherence, management strategy, treatment, pharmacist intervention, losartan responder rates, African American responses, the elderly, and blood pressure control. This is therefore a quite unholy mix. There are also other obvious and immediate secondary practical differences, incompatibilities and inconsistencies likely to be present in this form of analysis. In the present work for instance, these might be, 1. The BP machines were not all standardised. In Stahl the home machine was not automatic. 2. The technique used in each case was too variable, from two resting measurements one minute apart to an averaging of 6 months' readings (Stahl). 3. Were the BPs taken lying, standing or sitting? It is not stated in 16 trials. 4. Were they singleton or multiple readings? Usually this is omitted. 5. Were all patients treated on-going and if so well, or badly? 6. Were the records sufficiently comparable – in one case (Stahl at report 19) one definition of diastolic hypertension was put at 120 mmHg? In another it was 85. 7. What were the proportions of male, female, adult or child? 8. Is one recording a sufficient entry criterion to this or any such trial? 9. Why were ambulatory measurements said to be excluded? And why should they be? In appendix A the authors state that the Broege and Rogers trials were in fact ambulatory and are included. 10. Were there any unacceptable contradictions in the results and findings of any two or more of the works? One notes the Artinian study (27) is particularly atypical in favouring intervention, when its interventions were far too rare. 11. Which doctors were paid? Payment always influences an outcome. 12. Which patients were paid? 13. The frequency range of the intervention recordings was too wide, varying from twice a day to once a week. All the trials suffer from this defect; the readings should be hourly or two hourly, as often as possible. That gets the baseline. Compliance is no problem, with life at stake. Constant reiteration provides the same information. 14. They were also all too long: the benefits of self-monitoring can be assessed in a few days. Daily self observations over three years (Stahl, report 19) is entirely misconceived. It repeatedly reconfirms itself. 15. The 2714 patients did not all have isolated essential HT. 16. The patients were in too diverse age groupings even where stated; one trial had a maximum age for inclusion of 18, another 35 and only one went above 80. Unless all the readings and observations are made in the same conditions for the tight purpose of the objectives to be proved or disproved they simply have no bearing on consolidated interpretations. The wide variations in the trials in base, treatment and methods and other design aspects, are admitted on page 146, in terms of wide degrees of heterogeneity. The statistical analyses used are too hypothetical applied to this highly practical subject. Thus the authors do accept there are severe limitations to the study and these must effectively declare the work as inconsequential. It is difficult to know why it was done, but it is obviously cheap. The investigation and the conclusions are well known in practice, and might in any event have been easily obtained again in any BP clinic over the course of a relatively short time and have given much more instructive contemporary information, and without the need to introduce the dubious concept of “publication bias”. The authors might also have included some rationale as to why any potentially consistent effect should (only) have been underestimated. The results are too specific in any event. Describing BPs to one decimal point is too punctilious. Whether a clinic manual reading could be regularly identically repeated to an accuracy of 1.5 mm Hg is also highly doubtful, even if sufficient consecutive beats were of the same pressure. Too much emphasis is placed on the significance of decimalised readings. The reasons that clinic BP control and target achievement are both increased as formulated in the first conclusion are important, if true. The authors say the reasons for this are unknown; the money used on this study might rather have been profitably used to elucidate this. The setting of interventions at home is almost certainly too exclusive. This is mentioned because of the doubt concerning the second conclusion. Haemorrhagic cerebral and cardiac events are typically diurnal and after exercise; the structural integrity of the vessel wall is overcome. It is a specific single event in each episode, a normally flexible artery, able to resist considerable BP elevations, fails, and the explanation usually offered is that exceptional pressure is the cause. White coat elevations and anxiogenic activity do therefore need normally to be protected against and home readings are not enough. Ambulatory readings are useful in high-risk cases. When the size of the standard, and even more so the “attenuated”, benefits are considered, as the authors conclude them, they are not likely to contribute much to any extra reduction in vascular complications in the labile mild to moderate hypertensive (unless with persistent diastolics greater than 120!). Home recordings are clearly good for continual control in undemanding circumstances, and as a corollary, all schools ought to teach BP recording to all children. Where responsibility for the prevention of the outcome of blood pressure treatment is taken by physicians in general and where the only risk factor for stroke and MI is that BP, then failure to control such BP properly, where stroke or MI does occur, would be reckless or negligent especially if regard were only to be paid to and decisions based on this sort of tacked together work. (For their £80,000 pa in the UK, doctors ought to be responsible for something. The authors do state that high BP is one of the most readily preventable causes of stroke, easily detected, and effectively the way to reduce risk is to reduce the BP. They say it is undertreated, and that nowadays must be culpable.) The time and effort spent dutifully trawling through this sort of work is quite disproportionate to any benefit which may be obtained from it. There is no adequate substitute for doing the real work oneself. Hopefully the new BMJ editor will pay more attention to minimising this kind of report (i.e. metaänalyses) appearing in the rational sections of the journal where practitioners of the future really ought only to be exposed to useful and truly paradigmatic material. If it is merely descriptive and reflective it wastes time, money and effort. The effort is in particular of having to read as here 18 or more opportune reports the abstractions from which are to be the source of new fact, while bearing in mind all 38 reports required to set the background. David Barnes LLB(Hons) Competing interests: None declared |
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Mervyn S. Gotsman, Professor Emeritus Hadassah University Hospital, Jerusalem, Israel
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It is good to read a large survey of randomised trials that prove current clinical practice. All my patients have a blood pressure manometer at home, record their pressures and pulse 3 times a day, maintain a diary and compare notes with me or their general practitioner once a month. This maintains patient and physician interest, allows perfect titration of treatment and clinical response, and preserves patient compliance. Competing interests: None declared |
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Willem J. Assendelft, General Practitioner, Head of Department Leiden University Medical Center, PO Box 2088, 2301 CB Leiden, The Netherlands
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In their systematic review (SR) on blood pressure control by home monitoring Cappucio et al. (1) report on the selection of trials according to the QUOROM-guidelines (Quality of Reporting of Meta-analyses) (2), which was advocated by an editorial in BMJ two years ago (3). However, I found out that the acronym was misspelled (QUORUM). I used the search option of BMJ (July 23rd, 2004) and found “quorum” in 19 articles, of which 11 citations were in relation to SRs (1;3-12). It was inaccurately quoted eight times in the text (of which one time in the related author’s response)(11), two times in the reference and two times in a figure. Ironically, it was misspelled in the text of third editorials, of which two, however, had QUOROM spelled correctly in the reference (3;6;8). Fortunately, QUOROM was quoted properly 19 times as well (references not added). JAMA has a better performance, with only one misquotation (in a reference) and 12 proper quotations. Acronyms have a widespread use in medical publications. However, if the acronym, as in QUOROM, does not follow the notation of the original meaning it leads to citation problems, as I just illustrated. I am enthusiastic about the free on-line full-text availability of BMJ. The in-text search option has great advantages and therefore I think accurate spelling is essential. Since I fully support the use of the QUOROM guidelines for SRs, I think it is worth paying extra attention to a correct spelling: QUOROM, not QUORUM. Reference List (1) Cappuccio FP, Kerry SM, Forbes L, Donald A. Blood pressure control by home monitoring: meta-analysis of randomised trials. BMJ 2004; 329(7458):145-0. (2) Moher D, Cook DJ, Eastwood S, Olkin I, Rennie D, Stroup DF. Improving the quality of reports of meta-analyses of randomised controlled trials: the QUOROM statement. Lancet 1999; 354(9193):1896-1900. (3) Smith R. A plea to authors: ensure your studies comply with guidelines. BMJ 2002; 324(7333):314. (4) Brocklebank D, Wright J, Cates C. Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering corticosteroids in asthma. BMJ 2001; 323(7318):896. (5) Campbell FA, Tramer MR, Carroll D, Reynolds DJ, Moore RA, McQuay HJ. Are cannabinoids an effective and safe treatment option in the management of pain? A qualitative systematic review. BMJ 2001; 323(7303):13. (6) Goldbeck-Wood S, Robinson R. BMJ introduces a fast track system for papers. BMJ 1999; 318(7184):620. (7) Holt S, Suder A, Weatherall M, Cheng S, Shirtcliffe P, Beasley R et al. Dose-response relation of inhaled fluticasone propionate in adolescents and adults with asthma: meta-analysis Commentary: Dosage needs systematic and critical. BMJ 2001; 323(7307):253. (8) Jefferson T, Demicheli V. Quality of economic evaluations in health care. BMJ 2002; 324(7333):313-314. (9) Jordan R, Gold L, Cummins C, Hyde C. Systematic review and meta- analysis of evidence for increasing numbers of drugs in antiretroviral combination therapy. BMJ 2002; 324(7340):757. (10) Mann H, Li J, Nathanson LA, Mills TJ, Netland KE, Paula R et al. Alteplase for stroke. BMJ 2002; 324(7353):1581. (11) Mitchell E, Sullivan F. A descriptive feast but an evaluative famine: systematic review of published articles on primary care computing during 1980-97. BMJ 2001; 322(7281):279-282. (12) Ram FSF, Wright J, Brocklebank D, White JES. Systematic review of clinical effectiveness of pressurised metered dose inhalers versus other hand held inhaler devices for delivering beta 2 agonists bronchodilators in asthma. BMJ 2001; 323(7318):901. Competing interests: None declared |
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Ingrid Mühlhauser, Professor University Hamburg, Unit of Health Sciences, Martin-Luther King Platz 6, D-20146 Hamburg
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Complex interventions with complex outcomes should not be combined in meta-analyses (1). In their meta-analysis on blood pressure control by home monitoring Cappuccio et al. have included our randomised controlled study on the evaluation of a structured treatment and teaching programme on hypertension in general practice (2). However, blood pressure self- monitoring was only one of several components of our intervention and blood pressure values only one of various interrelated effectiveness measures. We have defined the components of our hypertension teaching and treatment programme by evaluation of the literature, previous experience with a diabetes treatment and teaching programme for non-insulin dependent diabetes (3) and assessment of patients' views on hypertension and desires to participate in monitoring and treatment decisions (4). Important interconnected components of the programme are correct measurement of blood pressure, a validated diagnosis of hypertension, and blood pressure self monitoring by the patients; active involvement of patients in decision making and self-adaptation of (drug-)therapy; education for small groups of patients comprising 4 weekly sessions by physicians' assistants in the family physician's office; written curriculum and teaching materials; and a structured preparatory course for physicians and staff (1,2). In addition, blood pressure values cannot be used as an isolated outcome variable without considering individual treatment goals and intended changes in drug and non-drug therapy. In our study, blood pressure was significantly lowered, and at the same time, less medication was prescribed (1,2) as a result of the intervention. Finally, the importance of identical effect sizes may differ across patient groups. We had targeted patients with persistently uncontrolled hypertension whereas others might have studied untreated patients. Cappuccio et al. have not acknowledged these flaws of their meta- analysis. Present methodology of systematic reviews does not allow appraisal of complex interventions with multicomponent outcome measures such as self-management programmes (5). 1. Mühlhauser I, Berger M. Patient education - evaluation of a complex intervention. Diabetologia 2002;45:1723-33. 2. Mühlhauser I, Sawicki PT, Didjurgeit U, Jörgens V, Trampisch HJ, Berger M. Evaluation of a structrured treatment and teaching programme on hypertension in general practice. Clin Exper Hypertens 1993;15:125-42. 3. Kronsbein P, Jörgens V, Mühlhauser I, Scholz V, Venhaus A, Berger M. Evaluation of a structured treatment and teaching progamme on non- insulin-dependent diabetes. Lancet 1988;ii:1407-11. 4. Mühlhauser I, Sawicki P, Didjurgeit U, Jörgens V, Berger M. Uncontrolled hypertension in Type 1 diabetes: assessment of patients' desires about treatment and improvement of blood pressure control by a structured treatment and teaching programme. Diabet Med 1988;5:693-8. 5. Mühlhauser I. Systematic reviews do not allow appraisal of complex interventions. XI Cochrane Colloquium, Barcelona 2003, abstract book. Competing interests: None declared |
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Nick J Field, General practitioner Wincobank Medical Centre Sheffield S9 1NG
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Whilst I accept that the evidence would suggest that ambulatory BP readings are often lower than clinic readings, I would dispute the conclusion that BP monitoring at home results in "better BP values and improved control of hypertension". It may help to distinguish those with "white coat" hypertension from those with sustained hypertension, and may reduce overtreatment in some cases (although the significance of white coat hypertension appears to be unclear). However, I cannot see that this will "contribute to an important reduction in vascular complications in the hypertensive population", particularly in the context of underdiagnosis and undertreatment that the authors describe. Competing interests: Nick Field works a a GP under a PMS contract, and reducing BP readings helps his Quality and Outcome framework payments |
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Nasir Shariff, Senior House Officer Blackpool Victoria Hospital Blackpool FY3 8NR
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Cappuccio et al. reported the better blood pressure values in home monitored patients. Whether the better readings of blood pressures in the home recorded pressures as compared to “control” group seen in health care system could be translated to reduction in vascular complications is highly suspicious and could require long follow up. With the lowering of cut off values for treating hypertension, it could be better to over read and treat. A comparison of medians of blood pressures could have given better information of whether the higher measured blood pressures in hospital recorded patients was a general trend or was it confined to a small group of “white coat hypertensive patients”. If the medians were the same in the two groups then home measuring of blood pressures would be relevant to the few outliers who had higher pressures recorded in hospital settings. Competing interests: None declared |
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