Infant and toddler Type 1 diabetes mellitus: complications after 20 years’ duration

OBJECTIVE: To compare the effect of the prepubertal duration of diabetes on the occurrence of complications in two groups of patients after the same number of years of the disease. RESEARCH DESIGN AND METHODS: This multicenter study enrolled 105 patients aged 16-40.3 years; 53 were prepubertal at diagnosis (aged 0-3) and 52 were pubertal (Tanner stage) and aged 9-14.9. The mean duration of disease was 19.8 and 19.5 years for prepubertal and pubertal patients, respectively. In all patients, retinal photographs were taken and centrally graded. Urinary albumin excretion (UAE; 86 case subjects), blood pressure (BP; 89 case subjects), and lifetime HbA(1c) (72 case subjects) were also evaluated. RESULTS: The prevalence of diabetic retinopathy (DR) was higher in pubertal than in prepubertal patients, both for any grade DR (71 vs. 40%, P = 0.002) and for mild or more severe DR (P = 0.005). The prevalence of abnormal UAE was not different in the two groups. Hypertension was found only in three patients, all pubertal at diagnosis. In the small group with moderate-to-severe DR, lifetime HbA(1c) levels, as percentages above the upper normal reference value, were higher (P < 0.01) in prepubertal than in pubertal patients. CONCLUSIONS: If diabetes is diagnosed in infants or toddlers and the prepubertal duration of diabetes is very long, the patients seem to be protected against DR. This protection disappears if lifetime metabolic control is bad. Instead, when onset is at puberty, the DR risk is higher and less dependent on metabolic control and may be influenced by age-related factors, such as BP.