Background
The prevalence and distribution of glomerular diseases differs between countries, and the indication to perform a kidney biopsy varies in each center. In this study, we assessed the prevalence of primary and secondary glomerulopathies based on histological diagnosis, and their correlation with demographic and clinical data were evaluated.
Methods
It was included in the study 1051 kidney biopsies retrospectively reviewed between the years 2000 to 2018. Demographic, clinical and laboratory data of patients were assessed. The prevalence of primary glomerulonephritis (PG) and secondary glomerulopathies (SG), as well as tubulo-interstitial diseases (TID), hereditary nephropathies (HN) and other diagnosis, were described. The frequency of primary and secondary glomerulopathies was evaluated by age group, and their temporal variation in three time periods (2000–2005, 2006–2011, and 2012–2018) were reported.
Results
The prevalence of SG predominated (52.4%) followed by PG (29.6%), other diagnoses (10.7%), TID (6.6%) and HN (1.1%). In primary forms, focal segmental glomerulosclerosis (FSGS) prevailed (37.3%), followed by IgA nephropathy (IgAN, 24.4%), membranous nephropathy (MN, 18.6%) and minimal change disease (MCD, 8.4%). Lupus nephritis (LN, 41.1%) had the highest frequency in SG, and in sequence diabetic kidney disease (DKD, 17.8%), systemic vasculitis (SV, 10.2%) and secondary FSGS (2nd FSGS, 10%). Nephrotic syndrome was the most common clinical presentation in PG, and also in DRD and 2nd FSGS, whereas in IgAN and SV the nephritic syndrome was the main form of presentation. In the age group between 18–50 years, LN, FSGS and IgAN predominated, between 51–65 years the proportion of DKD and 2nd FSGS increased, and SV were more found in patients > 65 years. The temporal variation of PG in three time periods showed a statistically significant increase in IgAN (p = 0.001) and a reduction in FSGS (p < 0.001). In SG, there were a reduction in LN (p = 0.027) and increase in DKD (p < 0.001), with a tendency to decrease of 2nd FSGS (p = 0.053).
Conclusions
In this kidney biopsy registry, FSGS and IgAN were the prevalent diagnoses in PG, and LN and DKD in SG. Nephrotic syndrome was the major indication for biopsy. When comparing the temporal variation of glomerulopathies, there was a reduction in FSGS and an increase in IgAN in PGs, and in SGs a reduction of LN with an increase in cases of DKD.