Diabetes mellitus, lower myocardial perfusion worsen heart failure, death risk

Type 2 diabetes mellitus (T2DM) and a lowered myocardial perfusion seem to aggravate the risk of heart failure (HF) and/or all-cause mortality, a new study reports.

The study included 406 patients with ST elevation myocardial infarction, of whom 104 (mean age, 66.7±9.5 years; 52 percent male) had T2DM. All patients were treated with primary percutaneous coronary intervention. The Quantitative Myocardial Blush Evaluator (QuBE) was used to assess myocardial perfusion. Outcomes of interest were HF and all-cause mortality.

In the short-term follow-up (30 days), the composite between both endpoints occurred significantly more frequently in patients with vs without T2DM (9 percent vs 2 percent; p=0.01). This remained true in the long run, when patients were assessed at 6 years (40 percent vs 25 percent; p=0.02), but not in the midterm, at 1 year (p=0.1).

The between-group differences seemed to be driven by all-cause mortality, which was significantly more common in T2DM patients at 1 year (13 percent vs 5 percent; p=0.01) and at 6 years (35 percent vs 15 percent; p<0.001). At all three time points assessed, HF developed at comparable rates between groups.

QuBE scores were also significantly lowered in T2DM patients. In turn, participants with T2DM and QuBE score <9 AU had significantly poorer event-free survival, and were at the highest risk of death and developing new-onset HF.

Multivariate Cox proportional hazards analysis confirmed that in the overall study sample, T2DM was a significant risk factor for the composite outcome, increasing its likelihood by 50 percent (hazard ratio [HR], 1.50, 95 percent confidence interval [CI], 1.02–2.21). In the diabetic subpopulation, each unit increment in QuBE protected against the composite outcome (HR, 0.96, 95 percent CI, 0.92–0.99).