Survival data are presented for five groups of diabetic patients seen at the Joslin Clinic, Boston, between 1939 and 1959. Patients were white, Massachusetts residents, and diagnosed diabetic within twelve months of first visit to the Clinic. The data are analyzed in terms of crude survival rates, relative survival ratios and mortality “attributable” to diabetes after the elimination of competing causes.
The excess mortality rate experienced by diabetic patients increases with duration of diabetes. While persons with juvenile onset experience virtually no excess mortality in the first fifteen years of the disease, between the fifteenth and the twenty-fourth year they have an excess death rate of 1 to 1.5 per cent per year. In the older age groups the excess is larger and appears earlier.
The mortality attributable to diabetes increases with increasing age of onset. Females have higher attributable mortality rates than males, particularly among cases with onset after forty years of age.
Patients first seen in 1944 had substantially better survival rates than those first seen in 1939. However, between 1944 and 1959 no further improvement has been evident. This leveling off in the former decline in diabetes mortality has occurred at a point when diabetic patients still experience an excess mortality of approximately 30 per cent within the first twenty-five years of their disease.