An Inverse Relationship Between Age of Type 2 Diabetes Onset and Complication Risk and Mortality: The Impact of Youth-Onset Type 2 Diabetes.

OBJECTIVE: This study compared the prevalence of complications in 354 patients with T2DM diagnosed between 15 and 30 years of age (T2DM15-30) with that in a duration-matched cohort of 1,062 patients diagnosed between 40 and 50 years (T2DM40-50). It also examined standardized mortality ratios (SMRs) according to diabetes age of onset in 15,238 patients covering a wider age-of-onset range. RESEARCH DESIGN AND METHODS: Complication status was assessed according to a standard protocol and extracted from our electronic database. Survival status was ascertained by data linkage with the Australian National Death Index. SMRs were calculated in comparison with the background Australian population and analyzed according to age of onset. RESULTS: After matching for duration, despite their younger age, T2DM15-30 had more severe albuminuria (P = 0.004) and neuropathy scores (P = 0.003). T2DM15-30 were as commonly affected by metabolic syndrome factors as T2DM40-50 but less frequently treated for hypertension and dyslipidemia (P < 0.0001). An inverse relationship between age of diabetes onset and SMR was seen, which was the highest for T2DM15-30 (3.4 [95% CI 2.7-4.2]). SMR plots adjusting for duration show that for those with T2DM15-30, SMR is the highest at any chronological age, with a peak SMR of more than 6 in early midlife. In contrast, mortality for older-onset groups approximates that of the background population. CONCLUSIONS: The negative effect of diabetes on morbidity and mortality is greatest for those diagnosed at a young age compared with T2DM of usual onset. These results highlight the growing imperative to direct attention toward young-onset T2DM and for effective interventions to be applied before middle age.

Long-term complications and mortality in young-onset diabetes: type 2 diabetes is more hazardous and lethal than type 1 diabetes.

OBJECTIVE: To evaluate long-term clinical outcomes and survival in young-onset type 2 diabetes (T2DM) compared with type 1 diabetes (T1DM) with a similar age of onset. RESEARCH DESIGN AND METHODS: Records from the Royal Prince Alfred Hospital Diabetes Clinical Database, established in 1986, were matched with the Australian National Death Index to establish mortality outcomes for all subjects until June 2011. Clinical and mortality outcomes in 354 patients with T2DM, age of onset between 15 and 30 years (T2DM15-30), were compared with T1DM in several ways but primarily with 470 patients with T1DM with a similar age of onset (T1DM15-30) to minimize the confounding effect of age on outcome. RESULTS: For a median observation period of 21.4 (interquartile range 14-30.7) and 23.4 (15.7-32.4) years for the T2DM and T1DM cohorts, respectively, 71 of 824 patients (8.6%) died. A significant mortality excess was noted in T2DM15-30 (11 vs. 6.8%, P = 0.03), with an increased hazard for death (hazard ratio 2.0 [95% CI 1.2-3.2], P = 0.003). Death for T2DM15-30 occurred after a significantly shorter disease duration (26.9 [18.1-36.0] vs. 36.5 [24.4-45.4] years, P = 0.01) and at a relatively young age. There were more cardiovascular deaths in T2DM15-30 (50 vs. 30%, P < 0.05). Despite equivalent glycemic control and shorter disease duration, the prevalence of albuminuria and less favorable cardiovascular risk factors were greater in the T2DM15-30 cohort, even soon after diabetes onset. Neuropathy scores and macrovascular complications were also increased in T2DM15-30 (P < 0.0001). CONCLUSIONS: Young-onset T2DM is the more lethal phenotype of diabetes and is associated with a greater mortality, more diabetes complications, and unfavorable cardiovascular disease risk factors when compared with T1DM.