Purpose: In the present study, the objective is to determine the epidemiological risk factors in the appearance of diabetic retinopathy and nephropathy in 112 Type 1 diabetic patients after 15 years.

Methods: A 15-year follow-up study was done in a cohort of 112 consecutive Type 1 (IDDM) diabetes mellitus patients without diabetic retinopathy or nephropathy at enrolment in 1990. We studied the incidence of diabetic retinopathy and/or microalbuminuria. The epidemiological risk factors included in the study were gender, diabetes duration, HbA(1c) levels, arterial hypertension, levels of triglycerides and fractions of cholesterol (HDL-cholesterol and LDL-cholesterol).

Results: The incidence of diabetic retinopathy was 55.40% at the end of study; the risk factors associated were duration of diabetes mellitus (P<.001), high levels of HbA(1c) (P=.009), presence of arterial hypertension (P=.007) and high levels of LDL-cholesterol (P=.002). The incidence of microalbuminuria was 41.07% and that of overt nephropathy, 19.60%; the risk factors associated were high levels of HbA(1c) (P<.001) and presence of arterial hypertension (P=.023). At the end of study, four groups of patients were formed: patients without microalbuminuria or retinopathy, patients with microalbuminuria only, patients with retinopathy only and patients with retinopathy and microalbuminuria. From the results of the discriminate analysis, we may assume that for the development of retinal lesions only, in the diabetes mellitus, the duration of the disease, the high levels of HbA(1c) and the arterial hypertension are most important, and for the development of renal and retinal lesion simultaneously, the important factor is poor control of glycemia measured by levels of HbA(1c) and arterial hypertension.

Conclusions: In conclusion, microalbuminuria correlated well with severe forms of diabetic retinopathy, and at the end of the study, two groups of patients had been configured: the first group had developed only diabetic retinopathy, and the second, their patients with diabetic retinopathy together with renal lesion (microalbuminuria). For the first group, the duration of diabetes mellitus was the most important risk factor, and for the second group, the levels of HbA(1c) and blood pressure were the most important.