In diabetic patients with acute myocardial infarction (MI), prognostic value of glycosylated hemoglobin (HbA1c) remains debated.

In a large observational study, we aimed to identify the prognostic value of HbA1c measured on admission for acute MI in diabetic patients regarding one-year major adverse cardiovascular events (MACE).

From the RICO survey database, all consecutive patients with or without known diabetes with acute MI (n=3005) from January 2001 to June 2016 were included. We divided our population into 4 quartiles: HbA1c≤6.5% (n=807), 6.5–7% (n=722), 7.2–8.1% (n=748),≥8.2% (n=728) for the analysis.

On admission, median age was 73 years old, median HbA1c and glucose were 7.0% and 9.6mmol/L. Compared to HbA1c≤6.5% group, HbA1c≥8.2% group was made up of younger persons (74 vs. 70 years old, P<0.001), had most important body mass index>30kg/m² (221 (28%) vs. 241 (33%), P=0.041), had less important high blood pressure rate (610 (76%) vs. 508 (70%), P=0.016) and had a stronger anti-diabetic treatment (insulin plus oral anti-diabetic medication: 44 (6%) vs. 176 (24%), P<0.001). Regarding the clinical data, HbA1c≥8.2% group had more STEMI [372 (46%) vs. 395 (54%), P=0.002], more multi-vessel disease [446 (60%) vs. 455 (67%), P=0.007] but lower GRACE score (156 vs. 150, P=0.020) than HbA1c≤6.5% group. We did not observed any difference concerning one year MACE between the 4 groups [HbA1c≤6.5%: 243 (30.1%); 6.6–7.0%: 227 (31.4%); 7.1–8.1%: 246 (32.9%);≥8.2%: 239 (32.8%), P=0.6].

Even in case of extreme glycometabolic chronic derangement, our results showed that the initial HbA1c has no one-year prognostic significance value after acute MI in our large diabetic population. However, these patients remain in a high-risk cardiovascular population and need close multidisciplinary follow-up. The chronical hyperglycemia prognostic value should be studied over a much longer period.