Tight BP control associated with improved outcomes in diabetics

Hypertension treatment reduces mortality and cardiovascular events in patients with type 2 diabetes, but it is underused, according to 2 recent studies.

A meta-analysis of 40 trials with more than 100,000 participants looked at associations between blood pressure treatment and vascular disease in patients with type 2 diabetes. It found that every 10-mm Hg reduction in systolic pressure was associated with a significant reduction in risk of mortality (relative risk [RR], 0.87), cardiovascular events (RR, 0.89), coronary heart disease (RR, 0.88), stroke (RR, 0.73), albuminuria (RR, 0.83), and retinopathy (RR, 0.87). Results were published in the Feb. 10 Journal of the American Medical Association.

The researchers also divided the trials by whether the patients' mean baseline systolic pressure was above or below 140 mm Hg. According to that analysis, the under-140 group of patients saw significant benefit from hypertension therapy on only certain outcomes: stroke, retinopathy, and renal failure. Analyzing the data by drug class, researchers found that the only significant differences were in the outcomes of heart failure (diuretics and angiotensin-receptor blockers were associated with decreased risk, calcium-channel blockers with higher risk) and stroke (calcium-channel blockers were associated with lower risk, beta-blockers with higher).

The study authors concluded that blood pressure lowering was associated with improved mortality and other outcomes in diabetic patients with a baseline systolic blood pressure of 140 mm Hg or greater. However, patients with blood pressure between 130 and 140 mm Hg also saw benefits from treatment on certain outcomes, leading the study authors to differ from the eighth Joint National Committee and suggest that hypertension treatment be considered at a lower threshold for certain patients, such as those with a history of cerebrovascular disease or mild nonproliferative diabetic retinopathy. The risk of adverse events from treatment should also be considered, they noted, and additional research is needed to help with individualized treatment decisions.

The study highlights the problem of clinicians' overreliance on guidelines and guidelines' overreliance on limited evidence, according to an accompanying editorial. Hypertension trials often focus on older patients, so clinicians may want to consider more aggressive blood pressure treatment in younger patients, especially those with albuminuria or other early manifestations of microvascular or macrovascular disease, the editorialist concluded.

Clinicians are not currently treating hypertension aggressively in diabetic patients, according to a study published by the Journal of General Internal Medicine on Feb. 4. Researchers analyzed the records of 771 patients with diabetes and blood pressure above 130/80 mm Hg who were treated at a large academic group practice between 2008 and 2011. Among patients with blood pressure above 130/80 mm Hg, 41% were diagnosed with hypertension and 37% were prescribed an antihypertensive. When a cutoff of 140/90 mm Hg was used, 52% were diagnosed with and 49% were treated for hypertension. The study authors concluded that interventions should target patients with multiple comorbidities to improve care for hypertension and diabetes.