Nationwide trends in blood pressure control among those with and without diabetes in England over last 2 decades: Health Survey of England 2003-2019
Authors: Graham C , Steckelmacher J , Capel M , Prasher J , Nicole Pereira N , Ahmed A , Poulter N , Sever P , Gupta A 
Published: October 2024

Diabetes and hypertension are both risk factors for cardiovascular disease (CVD), and often co-exist. Over recent decades practice guidance and health policy efforts have been made to improve population wide blood pressure (BP) control, particularly amongst those with diabetes, to reduce CVD. However, the nationwide impact of these ongoing efforts is yet to be documented comprehensively in England.

We used data from 11 serial nationally representative health surveys of England between 2003 and 2019 and compared BP control and presence of untreated hypertension amongst those with and without diabetes. These cross-sectional, randomly sampled surveys included 94,100 individuals cumulatively. We applied sample weights, accounting for oversampling and survey nonresponse, and transformations mitigating for survey equipment changes during this period. We used ‘period definitions’ to define those with diabetes and quantify BP control at the time of each coinciding survey, facilitating accurate comparison of trends over the sixteen-year period, while accounting for changes in understanding, variations in definitions, and shifts in medical practices. Python and STATA were used to conduct analyses and Join Point regression software was used to develop and compare trends.

In England, from 2003-2019, the prevalence of hypertension amongst those with diabetes and without diabetes decreased from 74.4% to 66.5% and from 32.6% to 27.1% (7.9% vs. 5.5%), respectively. This corresponded to reductions in population-wide mean systolic (S) and diastolic (D) BPs: compared to those without diabetes, those with diabetes had greater reduction in both SBP (7.9mmHg vs. 4.8mmHg) and DBP (2.7mmHg vs. 1.9mmHg) (Figure1). Both groups showed similar temporal improvement in BP-control amongst those with diagnosed hypertension, with those with diabetes showing better improvement in BP control compared to those without diabetes (14% vs. 12%). There was a significant difference in proportions of those with undiagnosed (unaware) hypertension amongst those with and without diabetes (11.4% vs. 30.0% respectively) (Figure2). Notably, there was no change in proportion of those with hypertension unaware about the condition (i.e. detection rate for hypertension in either of the group did not show any improvement over time).

These results suggest that we have been able to improve BP control over this period amongst those with and without diabetes, however, those without diabetes (more than 90% of population) have shown significantly poorer improvement. In addition, around one third of hypertensive patients amongst the no-diabetes group are unaware of the condition, and overall, the detection rates for hypertension in both groups have not improved in the last two decades. Lessons learnt from improving BP control amongst those with diabetes should be applied across the entire population, and newer strategies need to develop to improve detection of those with hypertension and are unaware.