| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 3494199 | The Lancet | 2010 | 10 Pages |
SummaryBackgroundUnexplained differences between classes of antihypertensive drugs in their effectiveness in preventing stroke might be due to class effects on intraindividual variability in blood pressure. We did a systematic review to assess any such effects in randomised controlled trials.MethodsBaseline and follow-up data for mean (SD) of systolic blood pressure (SBP) were extracted from trial reports. Effect of treatment on interindividual variance (SD2) in blood pressure (a surrogate for within-individual variability), expressed as the ratio of the variances (VR), was related to effects on clinical outcomes. Pooled estimates were derived by use of random-effects meta-analysis.FindingsMean (SD) SBP at follow-up was reported in 389 (28%) of 1372 eligible trials. There was substantial heterogeneity between trials in VR (p<1×10−40), 68% of which was attributable to allocated drug class. Compared with other drugs, interindividual variation in SBP was reduced by calcium-channel blockers (VR 0·81, 95% CI 0·76–0·86, p<0·0001) and non-loop diuretic drugs (0·87, 0·79–0·96, p=0·007), and increased by angiotensin-converting enzyme (ACE) inhibitors (1·08, 1·02–1·15, p=0·008), angiotensin-receptor blockers (1·16, 1·07–1·25, p=0·0002), and β blockers (1·17, 1·07–1·28, p=0·0007). Compared with placebo only, interindividual variation in SBP was reduced the most by calcium-channel blockers (0·76, 0·67–0·85, p<0·0001). Effects were consistent in parallel group and crossover design trials, and in analyses of dose-response. Across all trials, effects of treatment on VR of SBP (r2=0·372, p=0·0006) and on mean SBP (r2=0·328, p=0·0015) accounted for effects on stroke risk (eg, odds ratio 0·79, 0·71–0·87, p<0·0001, for VR≤0·80), and both remained significant in a combined model.InterpretationDrug-class effects on interindividual variation in blood pressure can account for differences in effects of antihypertensive drugs on risk of stroke independently of effects on mean SBP.FundingNone.
