Association between glycemic control and cardiovascular events in older Japanese adults with diabetes mellitus: An analysis of the Japanese medical administrative database

AIMS/INTRODUCTION: The relationship between glycated hemoglobin (HbA1c) and cardiovascular events in older adults was investigated using a Japanese administrative medical database. MATERIALS AND METHODS: Anonymized medical data on patients with diabetes mellitus aged ≥65 years for the period from January 2010 to December 2019 were extracted from the EBM Provider database. The primary end‐point was a composite of cardiovascular events, whereas the other end‐points included severe hypoglycemia and fracture. The association between cardiovascular events and HbA1c at the index date (i.e., approximately 10 months after initial diabetes mellitus diagnosis) was evaluated using the Cox proportional hazards model. RESULTS: Among the 3,186,751 patients in the database, 3,946 older adults with diabetes mellitus were eligible for inclusion and were subsequently grouped according to HbA1c quartiles at the index date. Cardiovascular events occurred in 142 patients. Patients with HbA1c in the highest quartile had significantly higher risk of hospitalization for cardiovascular disease than those with HbA1c in the lowest quartile (hazard ratio 1.948; 95% confidence interval 1.252–3.031, P = 0.003). However, the events risk was similar across subgroups with HbA1c <7.2%. The incidence of hypoglycemia and fracture was not significantly associated with the level of glycemic control. CONCLUSIONS: Among older adults with diabetes mellitus, those with poor glycemic control were at higher risk for cardiovascular events compared with those with better glycemic control. However, strict glycemic control had no effect on cardiovascular risk in patients with HbA1c <7.2%.