Hypertension in four African-origin populations: current 'Rule of Halves', quality of blood pressure control and attributable risk of cardiovascular disease

Objective To assess the public health burden from high blood pressure and the current status of its detection and management in four African-origin populations at emerging or high cardiovascular risk. Design Cross-site comparison using standardized measurement and techniques. Setting Rural and urban Cameroon; Jamaica; Manchester, Britain. Subjects Representative population samples in each setting, African-Caribbeans (80% of Jamaican origin) and a local European sample in Manchester. Main outcome measures Cross-site age-adjusted prevalence; population attributable risk. Results Among 1587 men and 2087 women, age-adjusted rates of blood pressure greater than or equal to 160 or 95 mmHg or its treatment rose from 5% in rural to 17% in urban Cameroon, despite young mean ages, to 21% in Jamaica and 29% in Caribbeans in Britain, Treatment rates reached 34% in urban Cameroon, and 69% in Jamaican- and British-Caribbean-origin women, Sub-optimal blood pressure control (>140 and 90 mmHg) on treatment reached 88% in European women, Population attributable risks (or fractions) indicated that up to 22% of premature all-cause, and 45% of stroke mortality could be reduced by appropriate detection and treatment, Additional benefit on just strokes occurring on treatment could be up to 47% (e.g. in both urban Cameroon men and European women) from tighter blood pressure control on therapy. Cheap, effective therapy is available. Conclusion With mortality risk now higher from noncommunicable than communicable diseases in sub-Saharan Africa and elsewhere, systematic measurement, detection and genuine control of hypertension once treated can go hand-in-hand with other adult health programmes in primary care. Cost implications are not great. The data from this collaborative study suggest that such efforts should be well rewarded. (C) 2001 Lippincott Williams & Wilkins.