[Study of the biopsied nephrotic syndrome for 20 years in the Cadiz Bay Area: histological correspondence, renal prognosis and clinical prognostic factors].

AIMS: To analyse the histological correspondence, the renal survival and the clinical prognostic factors in the nephrotic syndrome for more than 20 years in our environment as well as the influence of the nephrotic proteinuria in the renal survival in the different histological particular types of glomerulonephritis.

PATIENTS AND METHODS: Among the 542 primary and secondary glomerulonephritis diagnosed by kidney biopsy for two decades in the Cadiz Bay Area, we selected 242 patients whose clinical presentation and the biopsy indication was the nephrotic syndrome. Statistics methods: means +/- typical deviation, percentiles, percentages, Kaplan-Meier curves, long-rank test, student's t-test, chi-square analysis and Cox proportional hazards model test.

RESULTS: 242 patients with nephrotic syndrome (44.66% out of the total of glomerulonephritis), average age of 39.15 +/- 18 years old. Average proteinuria 6.75 +/- 4.53 g/day.

ETIOLOGY: membranous nephropathy (33.85%), lupus nephritis (14.46%), minimal change disease (11.57%), focal segmental glomerulosclerosis (10.33%), renal amyloidosis (9.95%). 33%, 45%, 63% and 72% of the patients with nephrotic syndrome developed to the End-stage Renal Disease and starting point of dialysis in 5, 10, 15 and 20 years respectively. After the multivariate model, the age older than 60 years old, the high levels of proteinuria and the coexistence with hypertension or renal failure, in the moment of diagnosis, showed to be independents clinical prognostic factors. The nephrotic proteinuria had a negative influence in the prognosis in the different histological types, especially in the IgA nephropathy and the lupus nephritis.

CONCLUSIONS: The nephrotic syndrome is the main indication of the renal biopsy in our environment. In general, as an independent group, its development is slowly progressive to the End-stage Renal Disease, having the possibility of being also conditioned by certain clinical factors present in the moment of the biopsy. The presence of nephrotic proteinuria is also a negative factor in the progression in many of the glomerulonephritis.