OBJECTIVE In young-onset diabetes, insulin therapy status is a rough marker of diabetes type. We describe the mortality experience of a low-income, predominantly minority population with diabetes diagnosed before age 30 years, stratified by insulin therapy.

RESEARCH DESIGN AND METHODS A total of 1,098 adults aged 40–79 years (median 49) diagnosed with diabetes before age 30 years and 49,914 without diabetes were recruited from community health centers. Individuals with diabetes were categorized by insulin therapy at baseline: group A, insulin therapy only; group B, insulin therapy and an oral hypoglycemic agent; and group C, no insulin therapy. Cox models were used to compute hazard ratios (HRs) and 95% CI for cause-specific mortality based on both underlying and contributing causes of death from death certificates.

RESULTS During follow-up (mean 3.9 years), 15.0, 12.5, and 7.3% of groups A, B, and C, respectively, and 4.6% without diabetes died. Compared with individuals without diabetes, HRs (CI) for all-cause mortality were 4.3 (3.4–5.6), 4.2 (2.8–6.3), and 2.0 (1.4–2.8) in groups A, B, and C, respectively. The leading cause of death was renal failure (end-stage renal disease [ESRD]) in group A, ESRD and coronary artery disease (CAD) in group B, and CAD in group C and individuals without diabetes. HRs for these conditions were at least twice as high as the HRs for all-cause mortality, reaching 17.3 (10.2–29.3), 17.9 (8.3–38.7), and 5.1 (2.3–11.7) in groups A, B, and C, respectively, for ESRD.

CONCLUSIONS Excess mortality persists among people with young-onset diabetes of long duration, with ESRD and CAD as the leading contributors to mortality.