Renal diseases: a 27-year renal biopsy study.

BACKGROUND

Data from registries of renal biopsy (RB), currently an important source for diagnosing renal disease, are available for a number of countries, but different patterns seem to exist in different countries.

METHODS

We reviewed the records of all patients who underwent an RB at our institution over a 27-year period (January 1, 1977, to December 31, 2003), in northern Portugal, a European region with a predominantly Caucasian population. We aimed at identifying patterns of glomerular disease frequency, as well as the corresponding changes over time. The patients were grouped for analysis in 9-year intervals: period A (1977 through 1985), period B (1986 through 1994) and period C (1995 through 2003).

RESULTS

Nephrotic syndrome was the most common clinical presentation for RB (42.0%), followed by urinary abnormalities (28.5%), acute renal failure (9.7%), chronic renal failure (9.3%) and nephritic syndrome (9.3%). Primary glomerulonephritis (GN) was the most common type of kidney disease in the present study, representing 50.4% of all renal pathology, followed by secondary GN (29.4%) and vascular and tubulointerstitial diseases (14.0%). The relative frequency of secondary GN and vascular and tubulointerstitial diseases increased significantly over time, and so did IgA nephropathy, the most common type of primary glomerular disease in the present study (31.2%). Focal and segmental glomerulosclerosis represented 6.9% of primary glomerular disease, and its frequency did not increase in the time period under study. Regarding secondary glomerular diseases, apparent changes were noted in the incidence of a number of diseases, including vasculitis, thin glomerular basement membrane disease and Henoch-Schönlein pur-pura. A somewhat similar situation was noted with vascular and tubulointerstitial diseases.

CONCLUSIONS

We conclude that, as occurs in other European and Asiatic populations, and unlike the findings in the American continent, IgA nephropathy is the most frequent glomerular disease in our population.