Background The impact of early initiation of diabetes care soon after the identification of hyperglycaemia rather than leaving diabetes untreated on changes in glycaemic control has not been fully clarified. We aimed to quantify the effect of initiating and continuing diabetes care compared with not starting management of diabetes on short-term changes in glycaemic control among the Japanese with newly screening-detected diabetes.

Methods We retrospectively reviewed data from a nationwide claims database to assess histories of physician-diagnosed diabetes or hyperglycaemia, as well as the use of antidiabetic agents, blood testing for hyperglycaemia or dietary advice among individuals without a history of diabetes care. Changes in glycated haemoglobin (HbA1c) concentrations were evaluated using baseline data and data from a health examination during the following year.

Results Among 1393 individuals with newly screening-detected diabetes, 62% (n=864) did not initiate diabetes management during the follow-up period; 49.2% (n=425) of the untreated group had poor glycaemic control (HbA1c ≥7%) at the baseline examination. Only 38% (n=529) began diabetes management in medical settings. Individuals who remained untreated had a 1.87 (95% CI 1.38 to 2.52) or 1.63 (1.10 to 2.41) times higher risk of absolute increases in HbA1c ≥0.5% or ≥1%, respectively, compared with the treated patients, a difference that was significant. Making more frequent clinic visits especially after the first visit was dose-dependently associated with improved HbA1c levels compared with no diabetes management.

Conclusions In comparison with a lack of management of diabetes, immediately initiating and continuing diabetes care after identification of hyperglycaemia in a screening setting would contribute to clinically meaningful, improved glycaemic control in the Japanese.