Antihypertensive treatment after stroke and all-cause mortality--an analysis of the General Practitioner Research Database (GPRD)

Abstract

Background: Randomised controlled trials have shown a beneficial effect of antihypertensive treatment on stroke recurrence. The effect of antihypertensive treatment on survival and recurrence in an unselected sample of the general population, using the General Practice Research Database, was analysed.

Methods: Cox regression estimating the effect of antihypertensive treatment on survival and stroke recurrence >1 year among 44,244 first-ever strokes in the UK from 1997 to 2006 was adjusted by propensity score analysis considering gender, age, general practice, stroke year, drug prescriptions and diagnostic codes from other diseases.

Results: The EU standardised stroke incidence was 118 per 100,000 (95% CI = 117-120). The 90-day case fatality was 19%. By 90 days after stroke 20,147 (58%) were diagnosed as having hypertension, of whom 75% had received antihypertensive treatment after stroke. After 5 years 68% of the hypertensive stroke patients receiving antihypertensive treatment were alive, while this proportion for patients not prescribed antihypertensive treatment was 59%. This could not be explained by potential confounders with an adjusted relative risk of 0.62 (95% CI = 0.58-0.66; p < 0.001) for antihypertensive treatment and premature death. The adjusted relative risk of antihypertensive treatment on stroke recurrence after 1 year, which was observed in 35% until 5 years after stroke, was 0.92 (95% CI = 0.84-1.01; p = 0.092).

Conclusions: A high proportion of hypertensive stroke patients did not receive antihypertensive treatment. The protective effect of antihypertensive treatment on survival was higher in this general population than reported in randomised controlled trials, while an effect of antihypertensive treatment on late stroke recurrence was borderline, but not significant.