Admission HbA1c and post-MI prognosis in patients without known diabetes: a meta analysis

Type of funding sources: None.

The association between newly diagnosed abnormal HbA1c and post-MI prognosis is unclear. Previous meta-analyses have included studies with both diabetic and non-diabetic patients or subsets of these patients.

To assess the association between HbA1c and post-MI prognosis in patients without known diabetes.

Cohort studies (up to Oct 2021) were retrieved from PubMed and Embase. We included studies that compared events in patients with newly diagnosed hyperglycaemia on admission HbA1c to those without. Studies where the hyperglycaemic groups had mixed known and newly diagnosed patients were excluded. Pooled risk ratios (RRs) and the 95% confidence interval (CI) were calculated using random effect model to assess the association between newly diagnosed diabetes and pre-diabetes and in-hospital, 30-day and ≥1-year mortality and MACE.

29 studies comprising 279719 patients were included. The pooled RR for in-hospital, 30-day and ≥1 year mortality in diabetic patients (Fig 1) were 1.94 [1.41-2.67], p<0.0001; 1.55 [1.02-2.34], p=0.04 and 1.69 [1.50-1.90], p<0.0001 respectively. Corresponding data for MACE were 1.78 [0.51, 6.18], p=0.36; 1.14 [1.01-1.28], p=0.03 and 1.40 [1.19-1.65], p<0.0001. In prediabetic patients (Fig 2), the corresponding RR for mortality was 1.28 [1.06, 1.55], p=0.009; 1.05 [0.85, 1.29], p=0.66 and 1.49 [1.21, 1.84], p=0.0002 and for MACE it was 4.63 [1.80, 11.90], p=0.001; 1.19 [1.05, 1.36], p=0.008 and 1.57 [1.24, 1.99], p=0.0002.

High HbA1c at admission in patients without known diabetes is associated with worse post-MI outcomes both in diabetic and prediabetic groups.