Prevalence of type 2 diabetes among acute inpatients and its impact on length of hospital stay in Japan

Objective The goal of this study was to determine the prevalence of type 2 diabetes among acute inpatients and evaluate its impact on the length of hospital stay in Japan. Research Design and Methods The discharge records of 2,120,170 acute inpatients who were 30 years old or older and discharged between July and December of 2008 were obtained from the Japanese administrative case-mix system, Diagnosis Procedure Combination (DPC), and allocated for analysis. Type 2 diabetes was defined by E11 of the ICD-10 coding system on patient records. Other types of diabetes, including type 1 diabetes and diabetes in pregnancy (defined by ICD-10 codes E10 E12-14 and O24, respectively) were excluded from the analyses. Results Type 2 diabetes was observed among 11.4% of the records, 9.9% of which were cases of diabetes as a comorbidity. Total length of hospital stay was 33,468,152 days, with diabetes patients occupying 13.9% of the total bed days. Patients with type 2 diabetes as a comorbidity had prolonged lengths of hospital stay compared to patients free from diabetes, and stratification by sex, age, surgical treatment, and disease category did not alter these results. The median length of hospital stay was 9 days among patients without diabetes and 13 days among patients with diabetes. Conclusion Japanese acute health care is experiencing an epidemic of type 2 diabetes, with 1 out of 10 acute inpatients suffering from the disease. Complication of type 2 diabetes is associated with prolonged length of hospital stay.