Low blood pressure levels & incident stroke risk among elderly Ghanaians with hypertension

Abstract

Background: Clinical trial data indicate that more intensive blood pressure (BP) lowering below standard cut-off targets is associated with lower risks of strokes in the elderly. There is a relative paucity of real-world practice data on this issue, especially among Africans.

Objective: To assess BP control rates, its determinants, and whether a lower BP < 120/80 mmHg is associated with a lower incident stroke risk among elderly Ghanaians with hypertension.

Methods: We retrospectively evaluated data, which were prospectively collected as part of a cohort study involving adults with hypertension and/or diabetes in 5 Ghanaian hospitals. BP control was defined using the JNC-8 guideline of <150/90 mmHg for elderly with hypertension aged >60 years or 140/90 mmHg for those with diabetes mellitus. Risk factors for poor BP control were assessed using multivariable logistic regression models. We calculated incident stroke risk over an 18-month follow-up at 3 BP cut-off's of <120/80, 120-159/80-99, and > 160/100 mmHg.

Results: Of the 1365 elderly participants with hypertension, 38.2% had diabetes mellitus and 45.8% had uncontrolled BP overall. Factors associated with uncontrolled BP were higher number of antihypertensive medications prescribed adjusted odds ratio of 1.45 (95% CI: 1.27-1.66), and having diabetes 2.56 (1.99-3.28). Among the elderly, there were 0 stroke events/100py for BP < 120/80 mmHg, 1.98 (95%CI: 1.26-2.98) for BP between 120 and 159/80-99 mmHg and 2.46 events/100py (95% CI: 1.20-4.52 at BP > 160/100 mmHg.

Conclusion: A lower BP target <120/80 mmHg among elderly Ghanaians with hypertension is associated with a signal of lower incident stroke risk. Pragmatic trials are needed to evaluate lower BP targets on stroke incidence in Africa.

Keywords: Africa; BP thresholds; Elderly; Stroke risk.