Prospective study of development of microalbuminuria and retinopathy in Brazilian IDDM patients

With the aim to study potential risk factors for the development of microal buminuria and retinopathy, baseline characteristics were examined in 50 Bra zilian IDDM patients followed for 4.48 years with a 2-year reexamination. D uring the study, 3 patients (6%) aged 25.9 +/- 4.4 years, duration of diabe tes 8.1 +/- 4.2 years, died from acute complications without microalbuminur ia and retinopathy after a follow-up of 2.1 +/- 0.7 years. The standardized mortality rate for the group was 0.84 per 1000 (95% CL, 0.31, 1.83) in com parison to 0.14 per 1000 in the general population. From 34 normoalbuminuri c individuals at baseline (urinary albumin excretion rate (AER) less than o r equal to 20 mu g/min in greater than or equal to 2 overnight urine collec tions), 10 developed microalbuminuria with an incidence density of 6.5 case s per 100 person-years (95% CL, 2.23, 10.16). Spontaneous normalization of AER was found in 2 of 4 patients with microalbuminuria at cycle 2. Multiple stepwise regression analysis demonstrated that baseline AER (p = 0.03), bu t not glycated hemoglobin, blood pressure or duration of diabetes, predicte d end-of-study AER. From 36 patients without retinopathy, 10 developed nonp roliferative retinopathy with an incidence density of 6.6 cases per 100 per son-years (95% CL, 2.75, 10.54). Retinopathy was associated with duration ( p = 0.05) and age at diagnosis of diabetes (p = 0.01). A tendency with base line AER (p = 0.06) was also noted. No patient developed macroalbuminuria, proliferative retinopathy or hypertension. By the end of our study, in a co hort of young IDDM patients followed in a developing country, 6% died from acute complications and 15 patients (44.1%) developed retinopathy and/or mi croalbuminuria. Our results suggest that the only predictor of end-of-study AER was baseline AER. Also, duration of diabetes and age at diagnosis appe ar to be risk factors for retinopathy.