Heart failure in patients with diabetes undergoing primary percutaneous coronary intervention

Diabetes mellitus is associated with increased risk after acute coronary syndromes. Primary percutaneous coronary intervention is the most effective method of reperfusion for acute ST-elevation myocardial infarction and can limit the ischaemic damage to the left ventricle. However, there are few data on the impact of diabetes mellitus on the risk of heart failure following primary percutaneous coronary intervention. We studied 958 ST-elevation myocardial infarction patients treated with primary percutaneous coronary intervention, of whom 263 (27.5%) had diabetes mellitus, with 67 (7.0%) treated with insulin. The primary end points of the study were re-admission for heart failure. Secondary end points were all-cause mortality and recurrent infarctions. The follow-up period was 5 years after hospital discharge. The cumulative incidence of re-admission for heart failure was 8.4%, 15.2% and 26.7% in patients without diabetes mellitus, non-insulin-treated and insulin-treated diabetes mellitus, respectively. Compared with patients without diabetes mellitus, the adjusted hazard ratio for heart failure was 1.95 (95% confidence intervals 1.30–2.93) and 3.09 (95% confidence intervals 1.71–5.60) in non-insulin-treated and insulin-treated diabetes mellitus, respectively. The corresponding hazard ratios for mortality were 1.03 (95% confidence intervals 0.68–1.55) and 2.04 (95% confidence intervals 1.22–3.42), respectively. There was a J-shaped association between fasting glucose levels in the acute phase and risk of mortality (P=0.0001) and a direct association with heart failure (P=0.03). Despite modern treatment of ST-elevation myocardial infarction and high levels of guideline-based medical care, diabetes mellitus had an independent adverse effect on the risk of re-admissions for heart failure, which was particularly high among insulin-treated patients.