Review: In diabetes, benefits of lowering BP depend on baseline BP being 140 mm Hg or more

Hypertension treatment reduced mortality and myocardial infarction in diabetic patients with a systolic blood pressure (SBP) of at least 140 mm Hg, a systematic review and meta-analysis found. However, in patients with lower baseline blood pressure (BP), treatment didn't affect overall mortality and was associated with increased cardiovascular (CV) mortality.

The study was published by The BMJ on Feb. 25 and was summarized in the March ACP Diabetes Monthly. The following commentary by Laura Larrea Mantilla, MD, and Victor M. Montori, MD, MSc, FACP, was published in the ACP Journal Club section of the June 21 Annals of Internal Medicine.

Establishing optimal BP targets in patients with and without diabetes remains controversial. The systematic review by Brunström and Carlberg supports the view that lowering BP is most beneficial for patients with higher BP levels who are at increased risk for adverse CV outcomes. Further, it provides context for studies showing that intensive BP control is not necessarily beneficial to all patients, such as those with mildly elevated BP, low CV risk, frailty, or multiple morbidities.

The controversy continues, in part because the evidence is primarily from industry trials designed to compare the efficacy of antihypertensive agents, often with placebo, rather than to evaluate specific BP targets or reductions. The reliability of the review is affected by use of summary rather than individual patient data (which increases the risk for so-called ecological bias in the analyses stratified by baseline mean SBP) and analyses stratified by attained SBP (an outcome of the trials).

Current guidelines seem to strike the right balance: After reduction of SBP levels to about 140 to 150 mm Hg, lower BP targets should take into account potential harms, inconvenience of additional treatment, personal and social contexts of patients, and CV risk and comorbidities. For many patients, perfect BP may turn out to be the enemy of “good enough.”