Implications of baseline glycemic control by plasma glycated hemoglobin A1c on adverse outcomes in patients with coronary heart disease and type 2 diabetes mellitus: Results from the PROMISE study.

Background: The optimal glycosylated hemoglobin (HbA1c) target in type 2 diabetes mellitus (T2DM) patients remains controversial, especially in patients with concomitant coronary heart disease (CHD). This study aimed to investigate the correlation between baseline HbA1c and long-term prognosis in CHD patients with T2DM. Methods: The study enrolled 6,839 CHD patients with T2DM and measured HbA1c at admission in a multicenter prospective observational cohort. Patients were divided into two groups according to baseline HbA1c levels: optimal glycemic control group (HbA1c < 7.0 %, n = 3023) and poor glycemic control group (HbA1c ≥ 7.0 %, n = 3816). The study endpoints were all-cause death and major adverse cardiac and cerebrovascular events (MACCEs). Results: The median follow-up period was 2.1 years. During this period, 229 (3.3 %) all-cause deaths, 165 (2.4 %) cardiac deaths, and 759 (11.1 %) MACCEs occurred. Unadjusted Kaplan-Meier analysis showed that the incidences of all-cause death, cardiac death, non-fatal MI, unplanned revascularization, and MACCEs were significantly lower in the HbA1c < 7.0 % group than in the HbA1c ≥ 7.0 % group (P < 0.05). Multivariate Cox hazard analysis indicated that the incidences of all-cause death, cardiac death and MACCEs were significantly lower in the HbA1c < 7.0 % group compared to the HbA1c ≥ 7.0 % group [all-cause death: hazard ratio (HR) 1.969, 95 % confidence interval (CI) 1.421-2.729; cardiac death: HR 2.515, 95 % CI 1.647-3.839; MACCEs: HR 1.345, 95 % CI 1.150-1.573; P < 0.001]. Conclusions: Baseline HbA1c level was associated with all-cause death, cardiac death, and MACCEs in CHD patients with T2DM.