A changing pattern of causes of death among diabetic patients during a 25-year period in the Osaka District, Japan

Abstract A total of 23,577 death certificates mentioning diabetes, in 10,927 cases as the underlying cause and in 12,650 cases as a contributory condition, were selected from approximately 1,000,000 death certificates filed in Osaka Prefecture, Japan, during a 25-year period between 1960 and 1984. These certificates were analyzed by use of a multiple coding system. The proportion of deaths associated with diabetes, which was only 0.88% of the total deaths in the period 1960–1964, increased to 3.49% in the period 1980–1984. It was also notable that the proportion of certificates with diabetes as the underlying cause of death to the total number of certificates mentioning diabetes decreased strikingly, from 60.8% in 1965–1969 to 36.8% in 1980–1984. Among diabetic subjects, the proportion of patients aged 65 years or over at death increased markedly during the same period, from 47.2% to 68.8%, and a clear increase in the mean age at death was apparent during the 25-year period. Remarkable changes in the underlying causes of death among diabetics were observed during the study period; an increase in disease of the circulatory system, and especially in disease of heart was noted. In the period 1980–1984, disease of heart exceeded cerebrovascular disease which had been the most frequent cause of death in diabetic subjects until that period. An increase in renal disease, including diabetic nephropathy, which was not observed in the standard analysis of underlying causes, was confirmed in the analysis of contributory conditions which was based on the multiple coding system.