Pre-infarction angina is associated with improved prognosis in diabetic patients with ST-elevation myocardial infarction - data from a contemporary cohort.

Background: Pre-infarction angina (PIA) is associated with improved prognosis in patients with ST-elevation myocardial infarction (STEMI). Some studies suggest that diabetes may blunt the effect of ischaemic preconditioning. We sought to study the impact of PIA in diabetic patients with STEMI.

Methods: Consecutive patients with STEMI who underwent primary angioplasty were included. PIA was defined as ≥1 episode of chest pain during the week preceding STEMI diagnosis. Incident major adverse cardiovascular events (MACE) were defined as the first occurrence of all-cause death, stroke or acute myocardial infarction.

Results: Of the 1143 included patients, 25% were diabetic and 32% had a history of PIA. Diabetic patients with PIA had smaller infarct sizes as estimated by peak creatine kinase (CK) [1144 (500-2212) vs. 1715 (908-3309) U/L, P = 0.003] and peak troponin [3.30 (1.90-6.58) vs. 4.88 (2.50-9.58) ng/ml, P = 0.002], compared to diabetics without PIA. They also had a lower likelihood of evolving with moderate to severe reduced left ventricle ejection fraction (LVEF) (25.6%, n = 22 vs. 46.6%, n = 82, P = 0.001). In non-diabetic patients, PIA was associated with reduced peak CK [1549 (909-2909) vs. 1793 (996-3078), P = 0.0497], but not troponin (3.74 [2.23-7.11] vs. 4.56 [2.44-7.77] ng/ml, P = 0.19), and was not associated with reduced LVEF (32.0%, n = 85 vs. 37.4%, n = 207, P = 0.13). Both diabetic and non-diabetic patients with PIA had a lower likelihood of evolving with a Killip class III/VI (non-diabetic patients: 5.6% vs. 14.1%, P = 0.002; diabetic patients: 12.8% vs. 24.6%, P = 0.049). Over a median follow-up of 18.0 (12.1-25.5) months, PIA was associated with a significant reduction in the incidence of MACE [hazard ratio 0.52, 95% confidence interval (CI) 0.37-0.74, P < 0.001], irrespective of diabetes status.

Conclusion: PIA is an independent predictor of favourable outcomes in the setting of STEMI for both diabetic and non-diabetic patients.