Does treatment of non-malignant hypertension reduce the incidence of renal dysfunction? A meta-analysis of 10 randomised, controlled trials.

OBJECTIVE: It remains controversial whether non-malignant 'benign' hypertension causes renal dysfunction. The effect of lowering blood pressure on the incidence of renal dysfunction among patients with non-malignant hypertension is not clear. This meta-analysis was conducted to determine whether antihypertensive drug therapy reduces the incidence of renal dysfunction in patients with non-malignant hypertension.
METHODS: Randomised, controlled trials of antihypertensive drug therapy of more than 1 year duration that reported renal dysfunction as an outcome were identified through MEDLINE search and literature review. A random effects model was used to obtain summary estimates.
RESULTS: Ten trials were identified, involving 26, 521 individuals and 114 000 person-years. All excluded subjects with advanced baseline renal disease. Definition of renal dysfunction outcome varied among trials but within each trial was applied similarly to both treatment and control groups. Drug treatment consisted mostly of diuretics and adrenergic blockers. Overall, treated patients had lower blood pressure and fewer cardiovascular events. There were a total of 317 cases of renal dysfunction. Patients randomised to antihypertensive therapy (or more intensive therapy) did not have a significant reduction in their risk of developing renal dysfunction (relative risk = 0.97; 95% confidence interval (CI) 0.78-1.21; P = 0.77).
CONCLUSIONS: Among patients with non-malignant hypertension enrolled in randomised trials, treated patients did not have a lower risk of renal dysfunction. The 95% CI suggests that a 25% or more true protective effect of antihypertensive drugs is unlikely.