OBJECTIVES: The effect of glycemic control on microvascular outcomes in people with Type 2 Diabetes (T2D) has been well-studied, but its impact on macrovascular outcomes is relatively uncertain, and long-term evidence from the real world is particularly scarce. We aim to examine the association between glycemic control and long-term macrovascular outcomes in T2D patients in China.

METHODS: Data were retrospectively extracted from a regional data platform (2006/1/1-2021/10/31) in Yinzhou, Ningbo, China. People aged ≥ 18 years with ≥ 1 T2D diagnosis and ≥ 1 hemoglobin A1c (HbA1c) record from 2007/01/01-2016/10/31 were included so that ≥ 5 years of follow-up was available. Index date was defined as the first HbA1c record date occurring ≥ 90 days after the first T2D diagnosis. Exposure was defined as attaining the glycemic target (HbA1c < 7.0%) at index ("index glycemic control") or at every measurement during follow-up ("sustained glycemic control"). Outcome was 3-point major adverse cardiovascular event (3P-MACE) including myocardial infarction, stroke, and cardiovascular death during follow-up, identified using clinical diagnoses and death records. Cox proportional hazard model was used to examine the association between glycemic control and the risk of 3P-MACE, with demographic and clinical characteristics adjusted.

RESULTS: A total of 7,049 individuals (mean age 61.4±11.4 years, 3,751 [53.7%] female) were analyzed. During a median follow-up of 6.7 years (interquartile range: 5.5–7.9), 3P-MACE occurred in 1565 (22.2%) patients at an incidence rate of 3.4 per 100 person-years. Index and sustained glycemic control were significantly associated with risk reduction in 3P-MACE (adjusted hazard ratio [95% confidence interval]: 0.86 [0.78-0.96] and 0.75 [0.65-0.87], respectively, both p<0.05).

CONCLUSIONS: Glycemic control at HbA1c < 7% is associated with significant risk reduction in long-term macrovascular outcomes in Chinese people with T2D. Diabetes treatments with better glycemic control may have value on the long-term cardio-cerebrovascular outcomes in T2D patients.