BMJ  2003;327:526-531 (6 September), doi:10.1136/bmj.327.7414.526

Paper

Prognosis for South Asian and white patients newly admitted to hospital with heart failure in the United Kingdom: historical cohort study

¹ Leicestershire Health Authority Department of Public Health Medicine, ² University of Leicester Department of Medicine and Therapeutics, Leicester Royal Infirmary, Leicester LE2 4NU

Abstract

Objectives To compare patterns of admission to hospital and prognosis in white and South Asian patients newly admitted with heart failure, and to evaluate the effect of personal characteristics and comorbidity on outcome.

Design Historical cohort study.

Setting UK district health authority (population 960 000).

Participants 5789 consecutive patients newly admitted with heart failure.

Main outcome measures Population admission rates, incidence rates for first admission with heart failure, survival, and readmission rates.

Results When compared with the white population, South Asian patients had significantly higher age adjusted admission rates (rate ratio 3.8 for men and 5.2 for women) and hospital incidence rates (2.2 and 2.9). Among 5789 incident cases of heart failure, South Asian patients were younger and more often male than white patients (70 (SD 0.6) v 78 (SD 0.1) years and 56.5% (190/336) v 49.3% (2494/5057)). South Asian patients were also more likely to have previous myocardial infarction (10.1% (n = 34) v 5.5% (n = 278)) or concomitant myocardial infarction (18.8% (n = 63) v 10.7% (n = 539)) or diabetes (45.8% (n = 154) v 16.2% (n = 817), all P < 0.001). A trend was shown to longer unadjusted survival for both sexes among South Asian patients. After adjustment for covariables, South Asian patients had a significantly lower risk of death (hazard ratio 0.82, 95% confidence interval 0.68 to 0.99) and a similar probability of death or readmission (0.96, 0.81 to 1.09) compared with white patients.

Conclusions Population admission rates for heart failure are higher among South Asian patients than white patients in Leicestershire. At first admission South Asian patients were younger and more often had concomitant diabetes or acute ischaemic heart disease than white patients. Despite major differences in personal characteristics and risk factors between white and South Asian patients, outcome was similar, if not better, in South Asian patients.

Introduction

People of South Asian origin (Indian (subcontinent) origin) comprise the largest ethnic minority group in the United Kingdom—4.1% of the population in 2001. The incidence of coronary heart disease is around 40% higher among this group than among the indigenous white population.^{1 2} Moreover, the onset of coronary heart disease has been suggested to be earlier and mortality higher in South Asian patients.^2-4 Some studies have shown a similar prognosis in South Asian and white patients after myocardial infarction.⁵ A high prevalence of coronary heart disease in South Asian people might be expected to result in a higher prevalence of heart failure, a major sequela of coronary heart disease. We compared population admission rates for heart failure and outcomes after first admission for heart failure in South Asian and white patients.

Methods

Data on admissions for heart failure were obtained from Leicestershire health information service. Our denominator was from 1991 census data for the local ethnic population. Data were obtained for patients aged 40 or over. Our principal measure was the ratio of standardised admission rates (South Asian patients to white patients) for men and women.

We obtained data on all Leicestershire residents, aged 40 or over, admitted with heart failure for the first time between 1 April 1998 and 31 March 2001. First admissions were defined as those where patients had no previous admission related to heart failure in these five years as a minimum. Ethnicity was that reported in the hospital discharge data.

Mortality was identified through the Office for National Statistics, and follow up hospital events were obtained from Leicestershire Health Authority data. Survival was measured from the date of first admission to the date of death, of readmission, or the end of follow up (30 September 2001). The main outcome measures were death from any cause (all cause survival) and all cause survival or emergency readmission for a cardiovascular event (event free survival).

Statistical analysis
Crude survival was estimated with the Kaplan-Meier method, and Cox proportional hazards modelling was used to investigate the influence of covariates on outcome. Potential modifiers of outcome included in the multivariate analysis were age, sex, ethnicity and social deprivation, and hospital comorbidity, such as diabetes, hypertension, renal insufficiency, stroke, and myocardial infarction.

Our proxy measure of social deprivation was from the index of multiple deprivation 2000 at electoral ward level expressed in fifths (lowest fifth being most deprived), matched using the domicile postcode of the patient at admission. As a proxy of general comorbidity we took the average hospital stay in each of the five years before the index admission. From these same five years we obtained information on conditions associated with heart failure, including acute myocardial infarction, other coronary heart disease, other than coronary heart disease, hypertension, heart valve disease, diabetes, stroke, renal failure, and atrial fibrillation or flutter.

Results

Between 1 April 1998 and 31 March 2001, 5789 patients were newly admitted with heart failure; 5057 (87.4%) of these were white patients and 336 (5.8%) South Asian patients. Follow up ranged from 183 to 1279 days, a minimum of six months for those alive at the end of the observation period. Ethnicity was recorded as not given for 347 (5.9%) patients, but personal characteristics suggested this group to be predominantly white.

Patients in the South Asian cohort were on average eight years younger than those in the white cohort. The South Asian cohort also had a higher proportion of men (190; 56.5%) than the white cohort (2494; 49.3%). Less than 10% (519) of patients were treated within a cardiological setting within seven days before or after the index admission. No difference was found between cohorts in this respect.

Acute myocardial infarction, both before and concomitant with the first admission for heart failure, was more prevalent in South Asian than white patients (before, 10.1% v 5.5%; concomitant, 18.8% v 10.7%). Similarly, diabetes mellitus and hypertension were more commonly recorded among South Asian patients. In contrast, white patients were more likely to have atrial arrhythmias, both before or concomitant with the admission for heart failure (table 1).

View this table: [in this window] [in a new window]   Table 1 Patterns of in-hospital comorbidity in five years before or concomitant with diagnosis of heart failure among white and south Asian patients. Values are numbers (percentages) of patients, with 95% confidence intervals, unless stated otherwise

 

Over half of all patients (51.4%; 2974) died before the end of follow up. Two thirds of all mortality (65.5%; 1948) was due to cardiovascular events. Crude survival analysis gave all cause case fatality rates at 30 days and one year of 21% and 42%, respectively, for the whole cohort and a median survival of 21 months (95% confidence interval 20 to 22).

Unadjusted inhospital case fatality rates were lower in South Asian patients than in white patients (13% v 19%). Estimates of survival at 30 days, one year, and two years (both to death and to combined event) were consistently higher for South Asian patients (see bmj.com). Univariate Cox regression showed a 38% lower risk of death and a 17% lower risk of readmission or death among South Asian patients.

On multivariate analysis the risk of death remained lower (18%) for South Asian patients whereas the risk of readmission was similar to white patients (table 2). Among the factors influencing outcome were age (44% increase in the risk of death per decade of life) and comorbidity, particularly stroke and renal failure. Adjusted outcomes were better for women. A diagnosis of diabetes or concomitant acute myocardial infarction was associated with poorer event free survival. A lower risk was found in patients with hypertension (hazard ratio for death and event free survival 0.77 and 0.88, respectively) or atrial arrhythmias (0.86 and 0.94). No clear relation was found between deprivation and outcome. Indeed patients living in the most disadvantaged areas (lower fifth) had lower mortality.

View this table: [in this window] [in a new window]   Table 2 Results of Cox proportional hazards modelling for all cause and cardiovascular mortality and for unplanned readmissions to hospital. Values are hazard ratios (95% confidence intervals)

 

After correction for covariates, the hazard ratio for all cause mortality was lower in South Asian patients than in white patients and similar for combined events (all cause, 0.82, 0.68 to 0.99; combined events, 0.94, 0.81 to 1.09; see table 2 and figure).

View larger version (21K): [in this window] [in a new window]   Survival model for South Asian and white patients in cohort of new cases diagnosed with heart failure in hospital between 1 April 1998 and 31 March 2001

 

In the five years before the admission with heart failure, 3.3% (n = 11) of South Asian patients had undergone a revascularisation procedure compared with 2.1% (n = 105) of white patients (P < 0.2). For procedures in the follow up period, values were 6.5% (n = 22) and 3.1% (n = 158), respectively (P = 0.001).

Discussion

Our study has the advantage of a homogeneous South Asian cohort (94% of the South Asian population in Leicestershire is of Indian descent), but we cannot assume that our observations apply to other ethnic groups, among whom cardiovascular risk profiles differ.⁶ Similar results were, however, shown in another study, where South Asian people of Pakistani or Bangladeshi descent were in the majority.⁷

Our study is limited by lack of information on disease severity, non-invasive investigations, and pharmacological treatment before and after admission, all potential modifiers of outcome. We are confident about the robustness of the record linkage system, which allowed identification of all mortality and inhospital events. Although the limitations of hospital discharge data cannot be ignored, such caveats apply equally to both ethnic cohorts and are unlikely to have introduced bias.⁷ In identifying incident cases we included all admissions with heart failure diagnosed in any position. Although this may cause some overestimate, excluding cases with a diagnosis of secondary heart failure may have led to more underestimation.

Coronary heart disease, the commonest cause of heart failure, is around 40% more common in patients from South Asian ethnic minorities in the United Kingdom and other countries compared with indigenous populations.^{1 2 8} Moreover, coronary heart disease has been reported to have earlier onset, to be more extensive, and to have a worse prognosis in South Asian people.^{2-4 9} Our data are compatible with a greater prevalence of coronary heart disease in South Asian people, with concomitant or previous myocardial infarction being nearly twice as common than in white patients. The younger age of the South Asian patients also supports earlier onset of disease. As might be expected, age adjusted rates for admission and incidence of heart failure were higher for South Asian patients.

Our study concurs with recent reports of an annual case fatality rate of 40% after a first admission for heart failure.^{10 11} A small proportion of our cohort was treated in a cardiological setting at the time of the index admission. In the context of previous reports from UK centres, indicating similar outcomes in South Asian and white patients after myocardial infarction and after coronary artery surgery, the lower mortality for South Asian patient newly admitted with heart failure is of note.^{5 12} This phenomenon is likely to be multifactorial and could be explained by heart failure being less advanced at the point of first admission, by a differing cause of heart failure in ethnic minority populations, or by better family support after discharge. Better prognosis among South Asian patients remained after adjustment for other prognostic variables and despite higher rates of coronary heart disease and diabetes. The higher prevalence of hypertension and diabetes in South Asian patients perhaps suggests that this cohort may have a higher prevalence of heart failure with preserved left ventricular systolic function. The protective effect of hypertension in our cohort lends some support to this postulate.

In the United States, black patients show more rapid disease progression with heart failure and are readmitted more frequently than white patients.^{9 13} Poorer prognosis for black and Asian patients in the United States after myocardial infarction has been ascribed in part to inequities in access to invasive procedures.^{14 15} Our observations do not support such phenomena in South Asian patients in Leicestershire, for whom coronary revascularisation rates were higher than in white patients. There is, however, a parallel to a large study from California where Asian patients (likely to be ethnically different to our South Asian population) had lower rates for admission to hospital, incidence, mortality, and readmission than white patients.¹⁶

What is already known on this topic Coronary heart disease is more prevalent among South Asian people than white people, with an earlier onset and higher mortality Ethnic minority patients are under-represented in clinical trials Little is known about the clinical features of heart failure and outcomes in South Asian patients in the United Kingdom What this study adds Admission and incidence rates for heart failure are higher in South Asian patients than in white patients South Asian patients newly admitted with heart failure are younger (average eight years) and have a history of a higher prevalence of acute myocardial infarction, diabetes, and hypertension than white patients Even after adjusting for age and in-hospital comorbidity factors, survival is similar, if not better, for South Asian patients

Better outcome for patients from areas of high deprivation is puzzling. As with all such measures, the index of multiple deprivation is a sum of indicators more relevant to the working age population than to elderly patients, who primarily comprised our cohort. Only two of the six domains in the index—housing and access to services (contributing no more than 20% of the overall weight)—could feasibly reflect the level of social deprivation among elderly patients. This indicates that the index is a relatively inappropriate measure of deprivation in this type of population. However short of knowing the current income or housing conditions, it is difficult to measure social deprivation in elderly patients.

Conclusions
Age adjusted admission and incidence rates for heart failure are higher among the South Asian ethnic population of Leicestershire than they are among the white population. Survival data suggest better outcomes for South Asian patients compared with white patients, this on a background of markedly differing risk factor profiles. The observations are clinically important to the UK South Asian population, among whom coronary heart disease and diabetes are common, and in whom the proportion of patients of an age that puts them at risk of heart failure is increasing. The data indicate that ethnicity is a significant factor in the development and course of the disease. Further studies are required to delineate the cause, clinical course, and prognosis of heart failure in different communities worldwide.

---

This is an abridged version; the full version is on bmj.com

Funding: JN is supported by the Nuffield Hospital, Leicester. The guarantor accepts full responsibility for the conduct of the study, had access to the data, and controlled the decision to publish.

Contributors: See bmj.com

Competing interests: None declared.

References

1. Lee J, Heng D, Chia KS, Chew SK, Tan BY, Hughes K. Risk factors and incident coronary heart disease in Chinese, Malays and Asian Indian males; the Singapore cardiovascular cohort study. Int J Epidemiol 2001;30: 983-8.[Abstract/Free Full Text]
2. Balarajan R. Ethnicity and variations in mortality from coronary heart disease. Health Trends 1996,28: 45-51.
3. Balarajan R. Ethnic differences in mortality from ischaemic heart disease and cerebrovascular disease in England and Wales. BMJ 1991;302: 560-4.
4. Wild S, McKeigue P. Cross sectional analysis of mortality by country of birth. BMJ 1997;314: 705-10.[Abstract/Free Full Text]
5. Muhktar HT, Littler WA. Survival after acute myocardial infarction in Asian and white patients in Birmingham. Br Heart J 1995;73: 122-4.[Abstract/Free Full Text]
6. McKeigue PM, Marmot MG, Adelstein AM, Hunt SP, Shipley MJ, Butler SM, et al. Diet and risk factors for coronary heart disease in Asians in north-west London. Lancet 1985;2: 1086-90.[CrossRef][Web of Science][Medline]
7. Heiat A, Gross CP, Krumholz HM. Representation of the elderly, women and minorities in heart failure clinical trials. Arch Intern Med 2002;162: 1682-8.[Abstract/Free Full Text]
8. Hughes K, Lun KC, Yeo PPB. Cardiovascular diseases in Chinese, Malays and Indians in Singapore. J Epidemiol Community Health 1990;44: 24-8.[Abstract/Free Full Text]
9. Lowry PJ, Glover DJ, Mace PJE, Littler WA. Coronary artery disease in Asians in Birmingham. Br Heart J 1984;52: 610-3.[Abstract/Free Full Text]
10. Stewart S, MacIntyre K, MacLeod MMC, Bailey AEM, Capewell S, McMurray JJV. Trends in hospitalisation for heart failure in Scotland 1990-1996. Eur Heart J 2001;22: 209-17.[Abstract/Free Full Text]
11. Jong P, Vowinckel E, Liu P, Gong Y, Tu JV. Prognosis and determinants of survival in patients newly hospitalized for heart failure. Arch Intern Med 2002;162: 1689-94.[Abstract/Free Full Text]
12. Goldsmith I, Lip GYH, Tsang G, Patel RL. Comparison of primary coronary artery bypass surgery in British Indo-Asian and white Caucasian population. Eur Heart J 1999;20: 1094-1100[Abstract/Free Full Text]
13. Alexander M, Grumbach K, Selby J, Brown AF, Washington E. Hospitalisation for congestive heart failure; explaining racial differences. JAMA 1995;274: 1037-42.[Abstract/Free Full Text]
14. Sheifer SE, Escarce JJ, Schulman KA. Race and sex differences in the management of coronary artery disease. Am Heart J 2000;139: 848-57.[Web of Science][Medline]
15. Taira DA, Seto DB, Marciel C. Ethnic disparities in care following acute coronary syndromes among Asian Americans and Pacific Islanders during the initial hospitalization. Cell Mol Biol 2001;47: 1209-15.[Web of Science][Medline]
16. Alexander M, Grumbach K, Remy L, Rowell R, Massie BM. Congestive heart failure hospitalizations and survival in California: patterns according to race/ethnicity. Am Heart J 1999;137: 919-27.[CrossRef][Web of Science][Medline]

(Accepted July 9, 2003)

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    StumbleUpon    Technorati    What's this?

Relevant Articles

Prognosis for South Asian and white patients with heart failure in the United Kingdom: Counterintuitive findings on heart failure in South Asians may be artefactual

Raj Bhopal and Colin Fischbacher
BMJ 2003 327: 1405-1406. [Extract] [Full Text]

Prognosis for South Asian and white patients with heart failure in the United Kingdom: Deprivation gradient in mortality should not be dismissed as artefactual

G Lyratzopoulos and R F Heller
BMJ 2003 327: 1406. [Extract] [Full Text]

Heart failure is more common but has better prognosis in South Asian patients
BMJ 2003 327: 0. [Full Text]

This article has been cited by other articles:

• Blackledge, H M, Squire, I B (2009). Improving long-term outcomes following coronary artery bypass graft or percutaneous coronary revascularisation: results from a large, population-based cohort with first intervention 1995-2004. Heart 95: 304-311 [Abstract] [Full text]  
• Ross, J. S., Mulvey, G. K., Stauffer, B., Patlolla, V., Bernheim, S. M., Keenan, P. S., Krumholz, H. M. (2008). Statistical Models and Patient Predictors of Readmission for Heart Failure: A Systematic Review. Arch Intern Med 168: 1371-1386 [Abstract] [Full text]  
• Newton, J D, Blackledge, H M, Squire, I B (2005). Ethnicity and variation in prognosis for patients newly hospitalised for heart failure: a matched historical cohort study. Heart 91: 1545-1550 [Abstract] [Full text]  
• Galasko, G I W, Senior, R, Lahiri, A (2005). Ethnic differences in the prevalence and aetiology of left ventricular systolic dysfunction in the community: the Harrow heart failure watch. Heart 91: 595-600 [Abstract] [Full text]  
• Lyratzopoulos, G, Heller, R F (2003). Prognosis for South Asian and white patients with heart failure in the United Kingdom: Deprivation gradient in mortality should not be dismissed as artefactual. BMJ 327: 1406-1406 [Full text]  
• Bhopal, R., Fischbacher, C. (2003). Prognosis for South Asian and white patients with heart failure in the United Kingdom: Counterintuitive findings on heart failure in South Asians may be artefactual. BMJ 327: 1405-1406 [Full text]  
• Malik, I. (2003). JournalScan. Heart 89: 1467-1468 [Full text]  

Rapid Responses:

Read all Rapid Responses

heart failure and south asians.

dr.manan vasenwala
bmj.com, 8 Sep 2003 [Full text]

Caution please

Kiran C Patel
bmj.com, 9 Sep 2003 [Full text]

Deprivation gradient in mortality should not be dismissed as artefactual

Georgios Lyratzopoulos, et al.
bmj.com, 25 Sep 2003 [Full text]

Asians with heart failure die younger

Michael D Sosin, et al.
bmj.com, 3 Oct 2003 [Full text]

Counterintuitive findings on heart failure in South Asians: consider artefacts

Raj S. Bhopal, et al.
bmj.com, 4 Nov 2003 [Full text]

Online poll

Find out more here>> and here>>