Antihypertensives associated with worse outcomes in diabetic patients with lower SBP
Blood pressure treatment goals should be less aggressive in people with diabetes than without diabetes, study authors said, because if systolic blood pressure (SBP) is already less than 140 mm Hg, additional agents might be harmful.
Among diabetic patients with a systolic blood pressure (SBP) below 140 mm Hg, antihypertensive treatment was associated with increased risk for cardiovascular death, according to a recent study.
Researchers performed a systematic review and meta-analysis of randomized, controlled trials published through February 2013 that included at least 100 diabetic patients who were treated for at least 12 months and that compared any antihypertensive agent with a placebo, 2 antihypertensive agents with another agent, or different target blood pressure values. Trials that directly compared 2 drugs to each other were excluded. The goal of the study was to determine how antihypertensive treatment at different blood pressure levels affects mortality and cardiovascular morbidity in diabetic patients. The outcomes examined were all-cause mortality, cardiovascular and noncardiovascular mortality, myocardial infarction, stroke, heart failure, end-stage renal disease, amputation, and blindness. The results were published by the BMJ on Feb. 25.
Overall, 49 trials involving 73,638 patients, most of whom had diabetes, were included in the analysis. Twenty-five of the trials, including 26,625 patients, were diabetic subgroups from larger trials, while the remaining 24, involving 47,113 patients, included only patients with diabetes. The researchers also obtained unpublished data from 12 of the 49 trials, involving 8,916 patients, by contacting pharmaceutical companies, authorities, or the authors.
For patients whose SBP was above 150 mm Hg at baseline, risk for all-cause mortality, cardiovascular mortality, myocardial infarction, stroke, and end-stage renal disease was reduced with antihypertensive treatment. For patients whose SBP was 140 to 150 mm Hg at baseline, additional antihypertensive treatment decreased risk for all-cause mortality, myocardial infarction, and heart failure. However, for patients whose SBP was 140 mm Hg or lower at baseline, additional antihypertensive treatment was associated with increased risk for cardiovascular mortality (relative risk, 1.15; 95% CI, 1.00 to 1.32). A tendency was also noted toward increased risk for all-cause mortality among these patients (relative risk, 1.05; 95% CI, 0.95 to 1.16).
The authors noted that most of the trials included in their analysis were designed to compare drugs versus placebo rather than to test blood pressure targets and that their results should not be generalized to patients with type 1 diabetes or those who have not received antihypertensive treatment, among other limitations. However, they concluded that while antihypertensive treatment reduces risk for death and cardiovascular morbidity in diabetic patients with an SBP above 140 mm Hg, additional treatment in those with an SBP less than 140 mm Hg is associated with increased risk for cardiovascular death and no additional benefit.
“[O]ur results, combined with those from the SPRINT [Systolic Blood Pressure Intervention Trial] …, suggest that blood pressure treatment goals should be less aggressive in people with diabetes than without diabetes,” the authors wrote. “This review strongly supports blood pressure treatment in people with diabetes mellitus if SBP is more than 140 mm Hg. If SBP is already less than 140 mm Hg, however, adding additional agents might be harmful.”