LAUSR

Background The number of patients with diabetes is increasing worldwide. Macrovascular disease, chronic kidney disease, chronic respiratory disease, cancer and smoking frequently accompany type 2 diabetes. Few data are available related to mortality of Asians with diabetes associated with these serious comorbidities. The present study aimed to quantify the excess mortality risks of type 2 diabetic patients with comorbidities. Methods We analysed the available records of 30,834 Japanese patients with type 2 diabetes from the BioBank Japan Project between 2003 and 2007. Men and women were followed up for median 8.03 and 8.30 years, respectively. We applied Cox proportional hazard model and Kaplan–Meier estimates for survival curves to evaluate mortality in diabetic patients with or without macrovascular disease, chronic respiratory disease, chronic kidney disease, cancer and smoking. Results Adjusted hazard ratios (HRs) for mortality were 1.39 (95% CI, 1.09–1.78) for male sex, 2.01 (95% CI, 1.78–2.26) per 10-year increment of age. Adjusted HRs of primary interest were 1.77 (95% CI, 1.42–2.22), macrovascular disease; 1.58 (95% CI, 1.08–2.31), chronic respiratory disease; 2.03 (95% CI, 1.67–2.47), chronic kidney disease; 1.16 (95% CI, 0.86–1.56), cancer; and 1.74 (95% CI, 1.30–2.31), current smoking. Conclusions Diabetic patients with a past or current history of chronic kidney, macrovascular or respiratory diseases or smoking habit have exhibited the highest risk of mortality. Data were limited to those of survivors of comorbidities but we propose the need to improve comorbidities and terminate cigarette smoking for better prognosis in patients with diabetes.