Focal segmental glomerulosclerosis in idiopathic membranous glomerulonephritis: a clinico-pathological and stereological study

Background. The phenomenon of focal segmental glomerulosclerosis (FSGS) in idiopathic membranous glomerulonephritis (IMGN) has not been adequately stud-ied. There is also a paucity of detailed glomerular morphometric and stereologic analyses data on renal biopsy in this association. Methods. Twenty-three (23) patients with IMGN and superimposed FSGS were compared to 35 patients with IMGN alone with respect to the clinical and laboratory features, light microscopic findings and stereologic parameters (glomerular cross-sectional area and estimated glomerular volume). Results. In the clinical parameters, patients with IMGN-FSGS had a significantly higher incidence of hypertension, raised serum creatinine and microscopic haematuria. The mean 24-h urinary protein excretion was higher in the group with IMGN-FSGS (7.4 ± 1.36 g) as compared to IMGN alone (3.85 ± 0.7 g, P < 0.001, Mann–Whitney test). On light microscopy, biopsies with IMGN-FSGS frequently had mesangial hypercellularity and more extensive tubulo-interstitial disease than those with IMGN alone. Stereological analysis showed that the non-sclerosed glomeruli in biopsies with IMGN-FSGS had a higher mean cross-sectional area (185466.7 ± 32493.3 µ 2 ) and higher estimated volume (855200 ± 152640 µ 3 ) as compared to glomeruli in cases with IMGN alone (76000 ± 14719.2 µ 2 and 576666.7 ± 131233.3 µ 3 , respectively). Conclusion. The present study is probably the first systematic analysis of stereologic parameters in renal biopsies of IMGN with FSGS. Our results objectively demonstrate the glomerular enlargement in the non-sclerosed glomeruli in cases of IMGN with FSGS. This detection of enlarged glomeruli may serve to alert the renal pathologist to the possibility of coexisting FSGS, which is a poor prognostic factor in IMGN. Abstract Background. We have reported a new equation (CKD-EPI equation) that reduces bias and improves accuracy for GFR estimation compared to the MDRD study equation while using the same four basic predictor variables: creatinine, age, sex and race. Here, we describe the development and validation of this equation as well as other equations that incorporate diabetes, transplant and weight as additional predictor variables. Methods. Linear regression was used to relate log-measured GFR (mGFR) to sex, race, diabetes, transplant, weight, various transformations of creatinine and age with and without interactions. Equations were developed in a pooled database of 10 studies [2/3 ( N = 5504) for development and 1/3 ( N = 2750) for internal validation], and final model selection occurred in 16 additional studies [external validation ( N = 3896)]. m linear age term terms in the magnitude of the at low creatinine the best RMSE the for diabetes and transplant did not improve performance. Equations with weight showed a small improvement in the subgroup with BMI < 20 kg/m 2 . Conclusions. The CKD-EPI equation, based on creatinine, age, sex and race, has been validated and is more accurate than the MDRD study equation. The addition of weight, diabetes and transplant does not significantly improve equation performance.