Mortality and causes of death in a national sample of diabetic patients in Taiwan

OBJECTIVE: To determine the mortality rate, causes of death, and standardized mortality ratio (SMR) in Taiwanese diabetic patients. RESEARCH DESIGN AND METHODS: A cohort of 256036 diabetic patients (118855 men and 137181 women, aged 61.2 +/- 15.2 years) using the National Health Insurance were assembled during the years 1995-1998 and followed up to the end of 2001. Deaths were verified by indexing to the National Register of Deaths. Underlying causes of death were determined from death certificates coded according to the ninth revision of the International Classification of Diseases. The general population of Taiwan was used as reference for SMR calculation. RESULTS: With a total of 1124348.4 person-years of follow-up, 43888 patients died and the crude mortality rate was 39.0/1000 person-years. Mortality rates increased with age, and diabetic men had a significantly higher risk of death than women. However, mortality rate ratio for men versus women attenuated with increasing age. The overall SMR was 1.63 (1.62-1.65), and SMRs also attenuated in the elderly. Causes of death ascribed to diabetes; cancer; cardiopulmonary disease; stroke; disease of arteries, arterioles, and capillaries; nephropathy; infection; digestive diseases; accidents; and suicide were 28.8, 18.5, 9.0, 10.5, 0.3, 4.8, 6.4, 7.9, 3.2, and 0.8%, respectively. CONCLUSIONS: Approximately 71.2% of the diabetes-related deaths would not be ascribed to diabetes on death certificates in Taiwan. The diabetic men have higher risk of dying than women, and diabetic patients have excess mortality when compared with the general population. For underlying causes of death not listed as diabetes, total cardiovascular death, including cardiopulmonary disease, stroke, and disease of arteries, arterioles, and capillaries, is the most common cause of death, followed by cancer.