Tight Blood Pressure Control Not Supported in Patients with Diabetes and Coronary Artery Disease

The INVEST findings revealed, in fact, a BP threshold below which patients with both diabetes and coronary artery disease have increased cardiovascular risk, said Rhonda M. Cooper-DeHoff, PharmD, University of Florida, Gainesville, FL.

Given the lack of evidence supporting SBP of <130 mm Hg, especially in diabetic patients, INVEST was conducted with an intent to determine the effect of SBP reduction on adverse cardiovascular outcomes in a cohort of 6,400 patients (mean age ~66 years) with diabetes and coronary artery disease.

The study tested the hypothesis that diabetic individuals who achieved SBP levels less than 130 mm Hg would have reduced cardiovascular outcomes compared with those achieving levels between >  =130 and <140 mm Hg.

Patients were randomised to BP-lowering therapy based on either a calcium-channel blocker or a beta blocker plus an angiotensin-converting enzyme inhibitor and/or a thiazide diuretic. The target was a BP of <130 mm Hg/<85 mm Hg.

For the analysis, patients were categorised according to the degree of BP control actually achieved: SBPs of >=140 mm Hg (not controlled), between >=130 mm Hg but <140 mm Hg (usual control), and <130 mm Hg (tight control). SBP control levels were distributed evenly with about one-third of patients falling into each of the groups.

The primary outcome was first occurrence of all-cause mortality, nonfatal myocardial infarction (MI), or nonfatal stroke.

During a mean follow-up of 2.7 years, combined death, MI, and stroke risk was not different between the tight-control and usual-control groups (12.7% vs 12.6%). Similarly, nonfatal MI (1.3% vs 1.7%), and nonfatal stroke (1.0% vs 1.3%) were similar for the 2 groups.

All-cause mortality was higher in the tight-control group (11.0%) than in the usual-control group (10.2%).

Extended follow-up out to >=5 years of the US cohort (n = 5,077) revealed a strong trend (P = .058) toward higher mortality for tight control than for usual control. After adjustment for baseline variables, the excess mortality hazard for tight control was 15%. The excess hazard in the US cohort was in patients with SBP <115 mm Hg, Dr. Cooper-DeHoff said.

"We concluded that in individuals with diabetes and documented coronary artery disease, systolic blood pressures <130 mm Hg are not beneficial, and we can probably rethink lower goals in this population." She added, "Efforts can be put toward lifestyle modification, where we know we can achieve benefit."

Results were reported at the 59th Annual Scientific Sessions of the American College of Cardiology (ACC) during a Late-Breaking clinical trial presentation.  [Presentation title: Rethinking Lower Blood Pressure Goals for Diabetic Patients With Coronary Artery Disease -- Findings From the International Verapamil SR - Trandolapril Study (INVEST). Late-Breaking Clinical Trials I]