A 15 YEAR FOLLOW-UP-STUDY OF PATIENTS WITH NON-INSULIN-DEPENDENT DIABETES-MELLITUS (NIDDM) IN OSAKA, JAPAN - LONG-TERM PROGNOSIS AND CAUSESOF DEATH

A 15 year follow-up study of diabetic patients was performed in Osaka, Japan. The subjects studied were 1939 patients with non-insulin depen dent diabetes mellitus (NIDDM), of whom 1000 (51.5%) were alive, 880 ( 45.4%) had died and 59 (3.0%) were untraceable at the end of 1993. The mortality rate per 1000 person-years of the subjects increased from 2 8.94 in 1960-1984 to 35.74 in 1985-1993, but the ratio of numbers of o bserved to expected deaths (O/E ratio) declined from 1.77 to 1.52 for the corresponding periods, suggesting an improvement in the prognosis for diabetic patients, with the exception of patients 65 years or over at the time of entry. Cerebro-cardiovascular and renal diseases were major causes of death, accounting for 48.4% of all deaths. In particul ar, disease of the heart was the cause of death in 20.5% of all deaths , cerebrovascular disease in 14.5% and renal disease in 12.0%. The O/E ratio was 11.30 for renal disease, which was remarkably high. The O/E ratios were 1.48 for malignant neoplasms, 3.02 for cancer of the live r and 2.15 for cancer of the pancreas. In the subjects less than 65 ye ars of age at entry, a significant decrease in the O/E ratio for overa ll deaths, malignant neoplasms, disease of the heart, cerebrovascular disease and renal disease was observed, but no notable difference in t he O/E ratio for ischemic heart disease was found between the periods 1960-1984 and 1985-1993. By contrast, in the case of subjects 65 years pr more at entry, the O/E ratios for overall deaths, malignant neopla sms, disease of the heart, ischemic heart disease and cerebrovascular disease increased markedly in the later period, while there was a cons iderable decline in renal disease indicated during this period. The an alysis suggested a structural change in causes of death of Japanese di abetic patients in recent years, with a relative increase in ischemic heart disease and a relative decrease in renal disease.