Trends in Diabetic Medication Use and Hypoglycemia Incidence Among Older Adults in Japan: A Retrospective Observational Study and a 10-Year Analysis Based on Level of Care Need Using Linked Medical and Long-Term Care Data

Background In Japan, the prevalence of diabetes among those aged 75 years and older is increasing with an aging population. The main goal of diabetes care is to prevent complications (such as diabetic nephropathy, retinopathy, neuropathy, and arteriosclerotic disease) while maintaining the quality of life. However, in older adults, glycemic targets must be individualized to avoid hypoglycemia, especially with medications, including sulfonylureas (SUs), glinides (GLs), and insulin, which pose a high risk of hypoglycemia. This study aimed to investigate the prescription trends of diabetes medications and the incidence of hypoglycemia among older diabetic patients aged 75 and above in Japan, stratified by their level of care need. This study analyzed 22,070-38,001 outpatients aged ≥75 years, assessing medication trends and hypoglycemia incidence (0.594% in 2013 to 0.316% in 2022). Methods This was a retrospective, observational study. Data were obtained from the Kokuho Database in Nara Prefecture (Nara KDB), linking medical and long-term care insurance records. This study included outpatients aged 75 and above with diabetes (excluding type 1) from 2013 to 2022. Patients were grouped as having care needs (HCN) or no care needs (NCN). The proportion of prescriptions for diabetes medications and hypoglycemia requiring intravenous glucose was annually assessed. Results From 2013 to 2022, the proportion of prescriptions for sulfonylureas (from 40.6% (N = 8,958) to 18.7% (N = 7,113)), intermediate-acting insulins (IIs) (from 8.17% (N = 1,804) to 1.79% (N = 681)), and rapid-acting insulins (RIs) (from 10.6% (N = 2,334) to 6.38% (N =2,424)) declined, similar to the incidence of hypoglycemia (from 0.594% (N = 131) to 0.316% (N = 120)). The incidence of hypoglycemia declined overall (0.594% to 0.316%), but that in HCN rose to 0.770% in 2022. The decrease in the incidence of hypoglycemia between 2013 and 2022 was statistically significant (p < 0.001). The number of long-acting insulin (LI) (from 5.66% (N = 1,250) to 8.13% (N = 3,091)) and glinide (from 4.78% (N = 1,055) to 5.87% (N = 2,231)) prescriptions increased. Dipeptidyl peptidase-4 inhibitors (DPP4Is) (from 56.8% (N = 12,540) to 72.6% (N = 27,573)) were the most commonly prescribed drugs. HCN consistently showed a higher proportion of hypoglycemia (from 1.25% (N = 54) to 0.824% (N = 43)) than NCN (from 0.434% (N = 77) to 0.235% (N = 77)). Conclusion Diabetes management in older patients in Japan has improved, with a continuing decline in the incidence of hypoglycemia. However, older adults with higher care needs remain more vulnerable to hypoglycemia, likely due to greater frailty and higher insulin use. This finding suggests the need for further individualized treatment strategies and close monitoring.