Abstract
Introduction: Focal segmental glomerulosclerosis (FSGS) is one of the most common causes of primary glomerular disease and its incidence is increasing worldwide. According to the morphological features, a group of nephropathologists proposed a standardized classification system, called the Columbia classification of FSGS in 2003.
Objectives: This study was carried out to define the frequency of FSGS variants, and their relationship with demographic and clinicopathological factors.
Patients and Methods: This cross-sectional study was conducted on renal biopsy reports at a nephropathology laboratory between 2009 to 2022. Out of 2100 patients, 345 renal biopsies had primary FSGS diagnosed by light and immunofluorescence microscopies, and classified according to the Columbia classification. The pathological, para-clinical, and demographic characteristics including gender and age were assessed.
Results: The mean age of 345 patients was 40.05±14.98 years. Regarding gender, 60.9% (n=210) of the patients were males. The mean serum creatinine and proteinuria in all patients were 1.54±0.91 mg/dL and 2267.94±1501.22 mg/d, respectively. The classic or not otherwise specified (NOS) variant was the most frequent variant. In this study, serum creatinine was significantly different among the five variants in which collapsing variant had higher serum creatinine 2.83±1.12 mg/dL. Similarly, proteinuria was higher in the collapsing variant, 2666.67±568.03 mg/d. A comparison of the mean age, serum creatinine, and proteinuria among genders showed a significant difference between male and female patients with males having higher mean age, 42.28±15.71 years, serum creatinine, 1.6822±1.02 mg/dL and proteinuria, 2434.67±1735.60 mg/d. In this study, the NOS variant was more prevalent in males, followed by the perihilar variant (n=57) and tip variant (n=56). Interstitial fibrosis was compared among different variants. It was significantly different among the variants, in which collapsing variant had higher interstitial fibrosis at 58.50±25.24%. On comparing the variants frequency, serum creatinine, proteinuria, and interstitial fibrosis among the age groups (40 years and less versus above 40 years) of patients with FSGS, the results showed no significant difference.
Conclusion: The results of this study showed that overall, the FSGS, NOS variant, was the most common morphological variant. However, the collapsing variant was more severe as compared to other variants. The disease was severe in males as compared with females. No significant difference was found in the frequency of variants or disease severity between elderly versus young FSGS patients.