All-Cause Mortality Trends in a Large Population-Based Cohort With Long-Standing Childhood-Onset Type 1 Diabetes

Abstract

OBJECTIVE Although management of type 1 diabetes improved dramatically in the 1980s, the effect on mortality is not clear. RESEARCH DESIGN AND METHODS We report trends in 30-year mortality using the Allegheny County (Pennsylvania) childhood-onset (age <18 years) type 1 diabetes registry (n = 1,075) with diagnosis from 1965–1979, by dividing the cohort into three diagnosis year cohorts (1965–1969, 1970–1974, and 1975–1979). Local (Allegheny County) mortality data were used to calculate standardized mortality ratios (SMRs). RESULTS As of 1 January 2008, vital status was ascertained for 97.0% of participants (n = 1,043) when mean age ± SD and duration of diabetes were 42.8 ± 8.0 and 32.0 ± 7.6 years, respectively. The 279 deaths (26.0%) observed were 7 times higher than expected (SMR 6.9 [95% CI 6.1–7.7]). An improving trend in SMR was seen by diagnosis cohort at 30 years of diabetes duration (9.3 [7.2–11.3], 7.5 [5.8–9.2], and 5.6 [4.0–7.2] for 1965–1969, 1970–1974, and 1975–1979, respectively). Although no sex difference in survival was observed (P = 0.27), female diabetic patients were 13 times more likely to die than age-matched women in the general population (SMR 13.2 [10.7–15.7]), much higher than the SMR for men (5.0 [4.0–6.0]). Conversely, whereas 30-year survival was significantly lower in African Americans than in Caucasians (57.2 vs. 82.7%, respectively; P < 0.001), no differences in SMR were seen by race. CONCLUSIONS Although survival has clearly improved, those with diabetes diagnosed most recently (1975–1979) still had a mortality rate 5.6 times higher than that seen in the general population, revealing a continuing need for improvements in treatment and care, particularly for women and African Americans with type 1 diabetes.