RESUMO
AIM: To investigate the influence of low glomerular filtration rate, as well as of systolic and diastolic hypertension, on microalbuminuria in patients with type 1 diabetes mellitus. METHODS: Twenty seven patients with type 1 diabetes mellitus (18 males, 9 females) were studied. All of the patients were below 50 years of age. In 93% of the cases, the duration of diabetes was less than 15 years. GFR was determined, after intravenous injection in the lying position, by using a 99m-Tc-DTPA, while microalbuminuria was calculated for the 24-hour urine using the nephelometric immunoassay (30-300 mg/24 h). The patients were divided into 3 groups according to the value of GFR. The values ranged from 90 to 125 ml/min/1.73 m2 were considered normal (in 63% of the patients in group 1), those above that range were considered as hyperfiltration (in 22.2% of the patients in group 2), while those below that range were considered as hypofiltration (in 13.8% of the patient in group 3). RESULTS: Data analyzed with the one-way ANOVA, indicated a significant statistical difference between the 3 groups in the duration of diabetes (p < 0.05), micro-albuminuria (p < 0.01), systolic BP (p < 0.01), diastolic BP (p < 0.05), fructosamine (p = 0.50), urea (p < 0.05), creatinine (p = 0.05), and uric acid (p < 0.05). Microalbuminuria correlated with the age of patients (p <0.05) (Spearman's rho), diabetes mellitus duration (p < 0.01), systolic BP (p < 0.05), diastolic BP (p < 0.05), LDL-cholesterol (p < 0.05). There was no statistically significant correlation between GFR and the other parameters. Hypertension, microalbuminuria, and the duration of diabetes correlated positively with the reduction of GFR, revealing the most frequent reduction of GFR in the patients with more than 15-year duration of diabetes. CONCLUSIONS: Hypertension and low GFR were associated with microalbuminuria in type 1 diabetes, while the duration of diabetes was shown to be the independent risk factor for the development of microalbuminuria.
