Effects of intensive blood pressure reduction on myocardial infarction and stroke in diabetes: a meta-analysis in 73 913 patients

Objective Guidelines generally recommend intensive lowering of blood pressure (BP) in patients with type 2 diabetes. There is uncertainty about the impact of this strategy on case-specific events. Thus, we generated estimates of the effects of BP reduction on the risk of myocardial infarction (MI) and stroke in diabetic patients. Methods We selected studies which compared different BP-lowering agents and different BP intervention strategies in patients with diabetes. Outcome measures were MI and stroke. We abstracted information about study design, intervention, population, outcomes, and methodological quality for a total of 73 913 patients with diabetes (295 652 patient-years of exposure) randomized in 31 intervention trials. Results Overall, experimental treatment reduced the risk of stroke by 9% (P=0.0059), and that of MI by 11% (P=0.0015). Allocation to more-tight, compared with less-tight, BP control reduced the risk of stroke by 31% [relative risk (RR) 0.61, 95% confidence interval (CI) 0.48-0.79], whereas the reduction in the risk of MI approached, but did not achieve, significance [odds ratio (OR) 0.87, 95% CI 0.74-1.02]. In a meta-regression analysis, the risk of stroke decreased by 13% (95% CI 5-20, P=0.002) for each 5-mmHg reduction in SBP, and by 11.5% (95% CI 5-17, P<0.001) for each 2-mmHg reduction in DBP. In contrast, the risk of MI did not show any association with the extent of BP reduction (SBP: P=0.793; DBP: P=0.832). Conclusion In patients with diabetes, protection from stroke increases with the magnitude of BP reduction. We were unable to detect such a relation for MI. J Hypertens 29: 1253-1269 (c) 2011 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins. Journal of Hypertension 2011, 29: 1253-1269