Association between visit-to-visit variability of glycemic indices and lipid profile and the incidence of coronary heart disease in adults with type 2 diabetes

Coronary heart disease (CHD) is one of the major causes of mortality and morbidity in patients with type 2 diabetes mellitus. In this study, we aimed to assess the association between visit-to-visit variability of fasting blood sugar (FBS), HbA1c, blood sugar 2 h post-prandial (BS2hpp), lipid indices, creatinine, systolic and diastolic blood pressure (SBP, DBP) and incident CHD in patients with type 2 diabetes during a median follow-up of ten years. The current case-cohort study consisted of 1500 individuals with type 2 diabetes, followed up for the occurrence of CHD from 2002 to 2019. The patients had at least four annual follow-ups during which glycemic and lipid profile were measured. Co-efficient of variance (CV) for each parameter was calculated by 10-21 measurements. Cox regression analysis was performed to assess the association between CV of glycemic indices, lipid profile, blood pressure, creatinine, weight and incident CHD during the follow-up period. Hazard ratios (HR) were adjusted for the confounding variables. Glycemic indices variability (i.e., CV-HbA1c, CV-FBS, and CV-BS2hpp), were significantly higher in the group with incident CHD (P=0.034, P=0.042, and P=0.044, respectively). Hazard ratios were 1.42 (95 % CI=1.13-2.09) for CV-HbA1c, 1.37 (95 % CI=1.02-2.10) for CV-FBS, and 1.16 (95 % CI=1.01-1.63) for CV-BS2hpp (P=0.012, P=0.046, P=0.038, respectively). Creatinine was significantly higher in the group with incident CHD (P=0.036) and it was significantly associated with higher incidence of CHD (HR=1.14, 95 % CI=1.02-2.17, P=0.048). Visit to visit variability of glycemic indices of the patients with type 2 diabetes is associated with incident CHD independent of their baseline and mean values.