Multimorbidity, Polypharmacy, Severe Hypoglycemia, and Glycemic Control in Patients Using Glucose-Lowering Drugs for Type 2 Diabetes: A Retrospective Cohort Study Using Health Insurance Claims in Japan

Abstract

Introduction: This study aimed to understand the actual status of multimorbidity and polypharmacy among patients with type 2 diabetes using glucose-lowering drugs, and to assess the effects of patient characteristics on severe hypoglycemia and glycemic control. Methods: We designed a retrospective cohort study using health insurance claims and medical checkup data in Japan from April 2016 to February 2021 and identified patients with type 2 diabetes who were prescribed glucose-lowering drugs. We analyzed data on patient characteristics, including multimorbidity and polypharmacy, calculated the incidence rate for severe hypoglycemic events, applied a negative binomial regression model to explore factors that affected severe hypoglycemia, and analyzed the status of glycemic control in the subcohort for which HbA1c data were available. Results: Within the analysis population (n = 93,801), multimorbidity was present in 85.5% and mean ± standard deviation for oral drug prescriptions was 5.6 ± 3.5 per patient, while for those aged 75 years or older these numbers increased to 96.3% and 7.1 ± 3.5, respectively. The crude incidence rate for severe hypoglycemia was 5.85 (95% confidence interval 5.37, 6.37) per 1000 person-years. Risk factors for severe hypoglycemia included younger and older age, prior severe hypoglycemia, use of insulin, sulfonylurea, two-drug therapy including sulfonylurea or glinides, three-or-more-drug therapy, excessive polypharmacy, and comorbidities including end-stage renal disease (ESRD) requiring dialysis. Subcohort analysis (n = 26,746) showed that glycemic control is not always maintained according to guidelines. Conclusion: Patients with type 2 diabetes, particularly older patients, experienced high multimorbidity and polypharmacy. Several risk factors for severe hypoglycemia were identified, most notably younger age, ESRD, history of severe hypoglycemia, and insulin therapy. Trial Registration: The University Hospital Medical Information Network Clinical Trials Registry (UMIN000046736).