Background and aims: Reduction of blood pressure (BP) and blood glucose diminish some microvascular complications of type 2 diabetes, but data on the combined effects of these interventions are sparse. Here we report effects of intensive BP control alone and in combination with intensive glycemic control on microvascular complications in the ACCORD BP trial.
Materials and methods: 4733 adults with type 2 diabetes (T2DM) and systolic BP (SBP) 130-180 mm Hg on 0-3 BP medications were randomized to intensive (target SBP <120 mm Hg) or standard (SBP <140 mm Hg) BP control, and separately randomized to intensive (target HbA1c <6.0%) or standard (HbA1c 7.0-7.9%) glycemic control. Pre-specified outcomes included one composite microvascular outcome measure (dialysis or renal transplantation, high serum creatinine [>3.3 mg/dL], or retinal photocoagulation or vitrectomy) and 9 single measures of kidney, eye, or peripheral nerve function. Proportional hazards regression models were used to assess two-way interactions between glycemia and BP treatment arm assignment for each microvascular complication.
Results: Over a mean follow-up of 4.7 years, the primary microvascular outcome occurred in 527 of 4733 participants, including 11.4% in the intensive BP arm and 10.9% in the standard BP arm (HR=1.08, 95% CI: 0.91-1.28). Whereas intensive glycemic control reduced the incidence of macroalbuminuria and a few other microvascular outcomes, intensive BP control only reduced development of microalbuminuria (HR=0.84, 95% CI:0.72-0.97). The observed reductions in microvascular outcomes by intensive glycemic control were not affected by the BP treatment arm (no interaction).
Conclusion: Intensive BP control improved only 1 of 10 pre-specified microvascular outcomes. None of the pre-specified outcomes were further significantly reduced in participants intensively treated for both glycemia and BP compared to those treated with either regimen alone, signifying the lack of an additional beneficial effect from combined intensive treatment.