Development and Worsening of Diabetes Among Adults Aged Over 40 Years: A 6-Year Follow-Up Study of 140,000 People in Japan – The Shizuoka Study

Abstract

Background Hemoglobin A1c (HbA1c) levels are commonly measured during health check-ups and used as an indicator of diabetes. However, the contribution of screening tests to the prevention of the future development of diabetes is scarcely analyzed. We evaluated the relationship between HbA1c screening results and future risk of diabetes development and worsening. Methods We used the Shizuoka Kokuho Database, a Japanese administrative claims database of insured persons aged > 40 years. Individuals available for follow-up during 2012–2017 and who had not received any diabetes treatment before 2013 were considered. We constructed logistic regression models to evaluate the association of the likelihood of initiating diabetes treatment by 2017 with the number of health check-ups received after 2013, HbA1c levels, and trend changes at the 2013 health check-up and assess the likelihood of using injection drugs. Results Overall, 137,852 individuals were analyzed. Compared to the normal HbA1c Group (HbA1c < 6.5%) with no trend changes, the normal group with improving trends had higher odds (odds ratio 22.64; 95% confidence interval 14.66–34.99) of starting treatment within 4 years. Among people with diabetes treatment initiated by 2017, injection drugs were more likely used in the normal group than in the diabetes group (HbA1c ≥ 6.5%). Higher numbers of health check-ups were significantly associated with lower likelihoods of starting injection drugs. Conclusions Good control of HbA1c levels, as indicated by the results of the health check-ups, might have led to insufficient attention to lifestyle habits, which might have resulted in a deterioration of glycemic control.