Ethnic differences in blood pressure monitoring and control in south east London

The burden of cardiovascular disease is unevenly distributed within the general population. For example, the incidence of coronary heart disease (CHD) has been shown to be consistently higher among South Asians, while the incidence of stroke is more common among African–Caribbean individuals compared to the white population. Furthermore, socioeconomically deprived populations experience higher rates of both heart disease and stroke.

Differences in the incidence of cardiovascular disease are largely related to the social distribution of cardiovascular disease risk factors, of which hypertension is the single most important. UK studies have shown an increased prevalence of hypertension (up to three or four times greater) among black people compared to the rest of the population. With regard to treatment, there is some evidence that detection rates are better for black compared to white patients. However, it is claimed that black patients on drug treatment for hypertension have overall poorer blood pressure control. While in the US this has been a consistent finding, this has not always been replicated in UK studies. This may be because these are based on either very small and geographically highly specific populations, or conversely, that they rely on national survey data which, despite oversampling, leads to a relatively small and diffuse black and ethnic minority (BEM) sample.

Looking at inequalities in terms of deprivation, there is evidence to show that the Quality and Outcomes Framework (QOF) has led to an incremental reduction in the inequalities gap. This is particularly so for blood pressure treatment, where a recent study has shown that differences between practice outcomes in the most and least deprived areas have narrowed to the point of convergence. The latter study also found the proportion of black residents in a practice area had the greatest confounding effect. Only one study has, so far, looked specifically at ethnic differences in blood pressure treatment since the QOF was introduced. This south west London study found that black patients with hypertension were significantly less likely to achieve QOF blood pressure targets compared to their white counterparts (odds ratio [OR] = 0.86, 95% confidence interval [CI] = 0.74 to 0.99). It is possible that, since then, there has been a reduction in ethnic inequalities in the same way that deprivation inequalities have reduced. This study set out to examine this by looking at ethnic inequalities in blood pressure monitoring and control, using recently collected data from a large sample of practices in Lambeth, south east London.