Introduction: Type II diabetes mellitus (DM) is a proinflammatory process and a known risk factor for major adverse cardiac events (MACE). The same inflammatory markers may be present in prediabetes (pDM); however, the relationship between pDM by HbA1c and MACE is not well studied. We sought to see if pDM increases one's risk for MACE.
Methods: We retrospectively studied patients at Beaumont Health, Michigan between 2006 and 2020. We divided patients into groups (G1-G5) based on haemoglobin A1c (HbA1c) trends over the study period as follows: G1: pDM patients who remained pDM; G2: pDM who progressed into DM; G3: pDM who normalized their HbA1c; G4: patients who maintained a normal HbA1c; and G5: patients with HbA1c persistently in the DM range. We compared MACE between the groups by univariate and multivariate regression analyses.
Results: A total of 119,271 patients were included in the study (G1: N = 13,520, G2: N = 6314, G3: N = 1585, G4: N = 15,018, G5: N = 82,834). Pairwise comparison revealed a statistically significant increase in the odds of MACE in all groups compared to those with normal HbA1c values (G4; p < .001). After adjusting for baseline characteristics, multivariate regression revealed elevated odds of MACE in patients with persistent pDM (G1; aOR = 1.087, p = .002) and diabetes (G2/G5; aOR = 1.25 and aOR = 1.18, p < .001) compared to individuals with normal HbA1c values.
Conclusion: Prediabetes is a risk factor for MACE. Normalization of HbA1c values appears to decrease the adjusted risk for MACE and should be the goal in patients with pDM.KEY MESSAGESPatients with prediabetes (pDM) are at increased risk for major cardiovascular events.Normalization of HbA1c in pDM patients may have a clinically significant benefit, in terms of lowering the MACE risk.Prediabetes patients who progress into diabetes mellitus may represent a particularly high-risk group.
Keywords: Prediabetes; haemoglobin A1c; major cardiovascular events.