Prognostic Implications of Type 2 Diabetes Mellitus in Ischemic and Nonischemic Heart Failure

Background: Heart failure (HF) is a common and serious complication in type 2 diabetes mellitus (T2DM). The prognosis of ischemic HF and impact of revascularization in such patients have not been investigated fully in a patient population representing everyday practice.

Objectives: This study examined the impact of ischemic versus nonischemic HF and previous revascularization on long-term prognosis in an unselected population of patients with and without T2DM.

Methods: Patients stratified by diabetes status and ischemic or nonischemic HF and history of revascularization in the Swedish Heart Failure Registry (SwedeHF) from 2003 to 2011 were followed up for mortality predictors and longevity. A propensity score analysis was applied to evaluate the impact of previous revascularization.

Results: Among 35,163 HF patients, those with T2DM were younger, and 90% had 1 or more associated comorbidities. Ischemic heart disease (IHD) occurred in 62% of patients with T2DM and 47% of those without T2DM, of whom 53% and 48%, respectively, had previously undergone revascularization. T2DM predicted mortality regardless of the presence of IHD, with adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of 1.40 (1.33 to 1.46) and 1.30 (1.22 to 1.39) in those with and without IHD, respectively. Patients with both T2DM and IHD had the highest mortality, which was further accentuated by the absence of previous revascularization (adjusted HR: 0.82 in favor of such treatment; 95% CI: 0.75 to 0.91). Propensity score adjustment did not change these results (HR: 0.87; 95% CI: 0.78 to 0.96). Revascularization did not abolish the impact of T2DM, which predicted mortality in those with (HR: 1.36; 95% CI: 1.24 to 1.48) and without (HR: 1.45; 95% CI: 1.33 to 1.56) a history of revascularization.

Conclusions: Ninety percent of HF patients with T2DM have preventable comorbidities. IHD in patients with T2DM had an especially negative influence on mortality, an impact that was beneficially influenced by previous revascularization.