Diabetes and hypertension in britain's ethnic minorities: implications for the future of renal servicesBMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7075.209 (Published 18 January 1997) Cite this as: BMJ 1997;314:209
- Veena Soni Raleigh, senior research fellowa
- Accepted 21 November 1996
Diabetes and hypertension are much more prevalent among Britain's 2.5 million Asian and African-Caribbean population than among the white population and are major contributors to end stage renal failure. Asians and African-Caribbeans have threefold to fourfold higher acceptance rates on to renal replacement therapy than white people, and in some districts they comprise up to half of all patients receiving such treatment. Their greater need for renal replacement treatment is accompanied by difficulties of tissue matching in cross racial transplants and a shortage of donor organs. The aging of ethnic minority populations will increase local need for renal services significantly. Measures to control diabetes, hypertension, and secondary complications in Asian and African-Caribbean communities will contribute both to safeguarding health and to economies in spending on renal services. Education about diabetes and hypertension, modification of behavioural risk factors, early diagnosis, effective glycaemic and blood pressure control, and early referral for signs of renal impairment are essential preventive measures. Primary and community health care professionals have a critical role to play here.
Diabetes and hypertension are major causes of disability and handicap, leading to premature death. Although end stage renal failure is a less common complication of diabetes and hypertension than coronary heart disease or stroke, treatment is both lifelong and expensive. The incidence of end stage renal failure therefore has significant consequences both for the health of local populations and for NHS resources. The national renal review estimated an increase over the next decade of 80% in the 20 000 or so patients receiving renal replacement treatment and a doubling of the current cost-about £300m a year-of providing renal services.1 2
Diabetes, hypertension, and renal failure are much more prevalent among Britain's 2.5 million Asians and African-Caribbeans than in the white population.3 4 The aging of these as yet young populations will have major implications for the future need for renal replacement treatment and highlights the urgent need for preventive measures.
About 4% of the UK population aged over 19 has diabetes, and 4-5% of total health care expenditure is spent on the care of people with diabetes.5 6 Diabetic nephropathy is a major underlying cause of end stage renal failure. Asians and African-Caribbeans have a high prevalence of non-insulin dependent diabetes mellitus, and among those who develop end stage renal failure it is predominantly non-insulin dependent diabetes that is implicated.
The prevalence of non-insulin dependent diabetes in Asians in the middle years of life is up to five times greater than in whites, and up to 20% of Asians aged 40-69 have this type of diabetes compared with about 5% of whites.7 The age at presentation is also significantly earlier, and the condition remains undiagnosed in up to 40% of Asian diabetics.8 9 Since duration of diabetes is one of the strongest risk factors for complications, this places Asians at greater risk.
Diabetic nephropathy and end stage renal failure are significantly more common in Asian diabetics than in white diabetics, with a relative risk of up to 14 reported from Leicestershire.10 Recent (1988-92) data for England and Wales show that mortality from diabetes among people born in the Indian subcontinent is about 3.5 times the national rate.11
People of African descent in Britain, the USA, and their countries of origin also have a high prevalence of diabetes, diabetic nephropathy, and end stage renal failure.12 13 14 Mortality from diabetes among African-Caribbean born men in England and Wales is about 3.5 times the national rate for men, with Caribbean women showing a sixfold excess.11
The World Health Organisation study group on diabetes notes that resources should be directed to improving the quality of preventive care in primary settings and to public health interventions for controlling non-insulin dependent diabetes.15 Low physical activity and obesity are significant risk factors in the development of insulin resistance and non-insulin dependent diabetes.16 17 The propensity of Asian people to central obesity7 and a sedentary lifestyle18 place them in the high risk category. Obesity is common also among African-Caribbeans.14 Because increased physical activity and control of obesity are the few known means of controlling insulin resistance, health education measures to promote physical activity and control obesity are likely to be the most important interventions for controlling the prevalence of diabetes among Asian and African-Caribbean people.
The Diabetes Control and Complications Trial in the USA demonstrated the effectiveness of strict blood glucose control in reducing renal (and other) complications of diabetes.19 Although the study related to insulin dependent diabetes, the consistency of treatment outcomes suggests that effects would be similar in all patients with diabetes. Information on blood glucose control and complications in non-insulin dependent diabetes will come from the UK Prospective Diabetes Study.20
The evidence to date, however, suggests that the quality of health care for Asian and African-Caribbean diabetics is inadequate and compliance poor.14 21 22 23 24 Often this is because patients lack knowledge about the disease, complications, and the importance of self management, as a result of poor communication, provision of inadequate or culturally inappropriate information, and non-availability of educational material in minority languages (fig 1).
One study noted that Asian diabetic patients knew less about the disease and its complications than their white counterparts. One third did not know why it was important to keep their blood sugar concentration low, 72% did not know that poor control resulted in complications, and 58% could not name a single complication.23 A study at the Manchester diabetes centre similarly showed deficiencies in the care of African-Caribbean patients compared with their white counterparts.24
Hypertension is a common condition, affecting 10-20% of the UK adult population. Because it is often asymptomatic, it often remains undiagnosed and untreated for long periods. It is a major cause of end stage renal failure. Compared with 10-20% of whites, 25-35% of African-Caribbeans are hypertensive.25 Recent (1988-92) mortality data for England and Wales show that mortality from hypertension among African-Caribbean born people is 3.5 times greater than the national rate, the excess in Caribbean born women being more than sixfold.11 The prevalence of hypertension is high in people of African descent throughout the world, and it results in greater end organ damage. Hypertension is the most common chronic disease in the Caribbean and among the 10 leading causes of death, and hypertensive renal failure is common.26 US data suggest that people of African descent may have an inherent susceptibility to hypertensive injury to the kidney.27 To a lesser extent, British Asians also have raised mortality from hypertension, with rates about 1.5 times the national rates.11
Although the cause of hypertension remains unclear and primary prevention may not always be possible, several modifiable risk factors have been identified: smoking, obesity, high alcohol intake, high salt intake, a sedentary lifestyle, and stress. African-Caribbeans experience many of these risk factors, with a higher body mass index, greater prevalence of diabetes, and evidence from the USA suggesting greater sensitivity to salt than whites.25 28
The prevalence of hypertension is typically associated also with low socioeconomic status and the poor access to and quality of care that often go with it: black people are among the most deprived of Britain's ethnic minorities. Research suggests that poor communication between African-Caribbean patients and their general practitioners often results in poor compliance with antihypertensive therapy and poorly controlled blood pressures.29
Diabetes and hypertension are major underlying causes of end stage renal failure, which is fatal without expensive, lifelong treatment. Compared with other services which purchasers are responsible for commissioning, renal services are of relatively low volume but high cost. The national renal review estimated the annual average cost per patient on dialysis at £23 000 and of a transplant at £12 000 with recurring annual costs of about £5400 for drugs and other treatment.1 2
The prevalence of end stage renal failure can be inferred from the numbers of patients receiving renal replacement treatment. The review of specialist services in London30 31 and the national renal review1 2 12 showed a threefold to fourfold higher rate of uptake of renal replacement treatment among Asians and African-Caribbeans than among whites, the relative risks rising steeply with age (fig 2). Analyses adjusting for area of residence show that this excess is not explained by higher referral rates resulting from inner city residence and proximity to renal units; instead it indicates greater need.12 Whether or not the higher rates of renal replacement treatment match overall need in these populations remains uncertain, since there are no ethnic data on those not referred, those referred but not treated, and those who die from renal failure before renal replacement treatment.
Diabetes is the major underlying cause of renal failure in ethnic minority patients receiving renal replacement treatment, the relative risk of end stage renal failure secondary to diabetes being 5.8 times greater in Asians and 6.5 times greater in African-Caribbeans than in whites.12 For hypertensive end stage renal failure the risk is fourfold in African-Caribbeans and 2.4 fold in Asians. Thus not only are African-Caribbeans and Asians more prone to diabetes and hypertension than whites, they are more likely to develop end stage renal failure as a consequence. The higher prevalence of end stage renal failure is reflected also in a threefold to fourfold excess mortality from renal disease among Asians and African-Caribbeans,11 as shown by the 1991 census based analysis of mortality data (fig 3).
The ethnic composition of local populations has an appreciable impact on local need for renal replacement services. In some districts with large ethnic minority populations the total number of patients receiving renal replacement treatment at any one time is over 700 per million population, compared with an average of 354 for the UK and 420 for the Thames regions.31 With the aging of ethnic minority populations, the impact of ethnicity on the need for renal replacement services will become even greater over the next decade. Population projections for ethnic minorities in London32 illustrate this effect: the number of elderly people in ethnic minorities is expected to triple between 1991 and 2011, with non-whites as a proportion of all Londoners aged 65 and over increasing from 5% to 17%.
Crude estimates based on ethnic and age specific rates of acceptance for renal replacement treatment in 1991-2 and the population projections for London suggest that between 1991 and 2001 the numbers of new Asian and African-Caribbean people accepted on to renal replacement programmes in London could rise by about 45%, increasing the proportion of these groups from 39% to 50% of all new receivers of renal replacement treatment, with corresponding increases in their proportion of overall patients. Health authorities with high proportions of Asian and African-Caribbean populations are therefore likely to need considerable additional investment in renal services to meet future needs, even if the current level of provision remains unchanged. If resource considerations constrain service provision ethnic minorities will be particularly disadvantaged.
Shortage of donor organs
Another issue is the shortage of donor organs and growing waiting lists resulting from falling road casualties. Transplants among ethnic minorities encounter additional constraints because of difficulties of tissue matching in cross-racial transplants and a reluctance to donate arising from religious concerns, poor awareness about the need for organ donation, and fears about the medical consequences.
Experience in the USA
The current American experience-of rising rates of diabetic renal disease, hypertensive renal damage, and renal failure in African-Americans-has considerable relevance for Britain. In 1990, 30% of patients receiving renal replacement treatment were African-American, even though they comprised only 12% of the total population (fig 4).13 Diabetes or hypertension are the underlying causes in over 70% of African-American cases of end stage renal failure. End stage renal failure is perceived as a major public health problem in the US, with the incidence of treated end stage renal failure rising 2.5 fold between 1977 and 1990, and the 200 000 patients receiving such treatment in 1990 costing about $7.3bn (£4.7bn) a year.33 The continued growth in the population needing dialysis will increase the cost to Medicare, which funds 80% of the expense, by $1bn every five years.
The way forward
Strategies for controlling diabetes and hypertension are likely to be most effective for reducing the risk of end stage renal failure among Asians and African-Caribbeans. (Such interventions will also reduce the incidence of other serious complications such as cardiovascular disease.) Educational interventions should target not only high risk middle aged people, but also adolescents and young adults, so that awareness of the disease and its effects are appreciated at an early age. Interventions to promote physical activity and control obesity among Asian and African-Caribbean communities should be consistent with lifestyles, diet, and cultural considerations. Antismoking measures are needed to reduce the risk of diabetic kidney damage. The future renal health of these communities is contingent also on these populations being aware of the disease within their communities and willing to accept the need for organ donation.
In areas with large Asian and African-Caribbean populations contracts should specify standards of care (primary and secondary) for ethnic minority patients with diabetes and systems for monitoring the quality of care and health outcomes. A participatory approach involving diabetic patients and carers from ethnic minorities in planning local strategies for diabetes care will make services more acceptable and effective. Self help and community based education forums where experiences and information can be shared create greater awareness about ways in which patients can manage their diabetes more effectively in culturally acceptable ways.
In areas with sizeable ethnic minority populations health authorities should consider establishing registers of diabetic patients so that their care, follow up, and outcome, and the prevalence of diabetes in local communities, can be closely monitored. The feasibility and cost effectiveness of screening for diabetes and hypertension should also be examined. The problem of undiagnosed diabetes and hypertension can in part be addressed within primary health care through opportunistic screening.
Providing health care services
The role of primary care in early diagnosis and effective management of diabetes and hypertension among ethnic minorities is critical for slowing the progression of renal impairment. Since the routine care needs of most patients with diabetes or hypertension are met within primary care, primary healthcare teams are well placed to offer opportunistic screening, early diagnosis, structured care, monitoring and control of blood glucose and blood pressure levels, and surveillance for complications. Because of the high prevalence and early onset of diabetes and hypertension among Asians and African-Caribbeans, primary health care and community professionals need to be vigilant in detecting the presence of these conditions and screening for complications.
Compliance with recommended dietary, lifestyle, and medical advice depends on good rapport with patients and involving them in their own disease management. Since the quality of self care is all important in both diabetes and hypertension, and day to day management of the condition is largely in the hands of the patients themselves, health professionals need to be familiar with the culture, customs, and sensitivities of their ethnic minority patients. They thus need to ensure that advice and treatment are integrated into traditional diets and lifestyles and that patients are aware of the risks and nature of complications associated with poor glycaemic and blood pressure control. Standards of care in general practice have a strong influence on outcomes in people with diabetes or hypertension. But the quality of care for ethnic minority patients is variable, and poor doctor-patient communication often results in poor metabolic and blood pressure control.
As early referral for treatment of end stage renal failure affects outcome, primary healthcare teams play an important role in identifying the groups at risk of renal failure and ensuring early referral. The number of patients with some degree of renal failure is low-up to 30 in a general practice of 10 000-so general practitioners sometimes fail to identify and refer patients. The review of London's renal services noted that up to half of patients presenting to renal units do so at the end stage of renal failure, when it is too late to arrest progression of the disease.30
The greater prevalence of diabetes, hypertension, and associated complications in British Asian and African-Caribbean communities needs to be addressed now in order to forestall a significant increase in the human and economic costs associated with these conditions. In particular, the future need for renal replacement treatment is likely to grow considerably unless effective measures are introduced among ethnic minority populations along the entire continuum of prevention-primary, secondary, and tertiary. Education, early diagnosis, and effective management of these conditions are important both for safeguarding the health of susceptible populations and for long term cost savings for the NHS.