Is the rule of halves still relevant today? A cross-sectional analysis of hypertension detection, treatment and control in an urban community.

AIMS

To estimate percentages of patients with undiagnosed hypertension, diagnosed untreated hypertension and diagnosed, treated and uncontrolled hypertension and to identify sociodemographic factors for diagnosed, uncontrolled hypertension and not having a blood pressure (BP) reading recorded.

METHODS

Data from 320 094 patients aged 18 to less than 80 years from general practices in inner London was analysed using both last recorded BP (blood pressure) and mean BP. Logistic regression models identified factors associated with uncontrolled hypertension and no recorded BP.

RESULTS

Twenty-nine thousand, seven hundred and nineteen (9.3%) patients had a recorded diagnosis of hypertension. On the basis of analysis of the last BP value, 14.2% (n = 4207) were untreated and 46.3% (n = 13 749) had uncontrolled hypertension; 10.0% (n = 28 274) without a prior hypertension diagnosis had undiagnosed hypertension. Corresponding values based on mean BP analysis were 8.9% (n = 2367) untreated, 51.5% (n = 13 734) uncontrolled; 4.1% (n = 11 446) undiagnosed. 17.5% (n = 55 960) had no recorded BP value.Black ethnicity was a predictor of uncontrolled hypertension: compared with the White British population, the adjusted odds ratio (AOR) for the Black African population was 1.39 (95% CI: 1.25-1.53) and for the Black Caribbean was 1.31 (95% CI: 1.19-1.45). The White Other group were most likely to have no record of BP measurement (AOR: 1.52; 95% CI: 1.47-1.57); conversely, unrecorded BP was less likely in the Black African (AOR: 0.79; CI: 0.74-0.83) and Black Caribbean (AOR: 0.71; CI: 0.66-0.76) groups, relative to the White British population.

CONCLUSION

In an inner-city, multiethnic population, the 'rule of halves' still broadly applies to the diagnosis and control of hypertension, although only a small proportion were untreated.