Aims: To determine the prevalence and the incidence of diabetic nephropathy in Type 1 diabetes mellitus in Spain and to investigate the risk factors for the development of microalbuminuria.
Methods: One thousand five hundred and two patients with Type 1 diabetes mellitus were prospectively followed in 15 hospital diabetes outpatient clinics in Spain. Blood pressure, body weight, HbA(1c), total cholesterol, HDL-cholesterol, triglycerides, plasma creatinine and urinary albumin excretion (UAE) were determined every 3-5 months.
Results: A total of 1225 patients (624 males and 601 females), age 30.7+/-9.3 years with diabetes duration of 14.1+/-9.1 years completed 4.3 (4.0-5.1) years of follow-up. At baseline 14.2 (95% CI 12.3-16.3)% of patients had microalbuminuria, 5.1 (3.9-6.4)% macroalbuminuria and 3.4 (2.5-4.6)% kidney failure. During follow-up the annual incidence of microalbuminuria was 2.7 (2.2-3.2)%. In a multiple logistic regression analysis the predictors of progression to microalbuminuria were initial UAE, HbA(1c), diabetes duration, smoking, and HDL-cholesterol <0.9 mmol/l.
Conclusions: The prevalence and incidence of diabetic nephropathy in Spain are comparable to data obtained in similar studies carried out in other countries. The development of microalbuminuria is associated not only with glycaemic control and hypertension, but also to the control of other risk factors such as dyslipaemia and smoking.