[Longitudinal observation of patients with subclinical stages of Balkan endemic nephropathy].

One hundred patients with Balkan endemic nephropathy, subclinical stage were complexly examined under clinical conditions, and later, in the course of 20 years they were subjects of followup care. The indices followed up revealed how slowly and gradually the characteristic clinical and laboratory signs of the disease were manifested. The duration of the disease was established to be far longer than that known so far (7-8 years), determined by anamnestic data of the patients about the disease onset, which usually coincided with some of the stages of the chronic renal insufficiency. Furthermore, by a long-term observation of the patients in the subclinical stage, it was established that the preazotemic stage of the disease was much longer than the azotemic. That fact is of great significance for the non-specific prophylaxis of the disease with a view to a further prolongation of its azotemic-free stage.