CLINICAL AND LABORATORY DISTINCTIONS IN PRIMARY VS. SECONDARY MEMBRANOUS NEPHROPATHY: INSIGHTS FROM WESTERN MEXICO

Introduction:

Membranous nephropathy (MN) is a leading cause of nephrotic syndrome in adults and exists in both primary and secondary forms. Differentiating between these forms is crucial for targeted treatment and accurate prognosis.

Methods:

This retrospective observational study was conducted at a tertiary care center in Western Mexico. We analyzed demographic, laboratory, and renal pathology data from patients diagnosed with MN, based on biopsies registered in the Glomerular Disease Registry, from January 2022 to January 2023.

Results:

A total of 81 patients were included, with a mean age of 35.4 years (SD ±16.3); 50.6% were female. Nephrotic syndrome was present in 75.3% of cases, while 37% had acute kidney injury (AKI) at presentation. The most common cause of secondary MN was lupus nephritis. Key findings included significantly higher proteinuria (13.1 vs. 6.4 g/day, p=0.001) and nephrotic syndrome prevalence (90.9% vs. 64.5%, p=0.014) in primary MN. Although serum albumin levels were lower in primary MN, the difference was not statistically significant. AKI was more frequent in primary MN (48.4% vs. 29.1%, p=0.077). PLA2r antigen was detected in 30.3% of primary MN cases, a lower prevalence than reported in other populations. Secondary MN was characterized by a higher incidence of extracapillary (22.9% vs. 3.03%, p=0.013) and endocapillary proliferation (58.3% vs. 3.03%, p=0.001).

Conclusions:

Our study identifies distinct clinical and laboratory features between primary and secondary MN in a Western Mexican cohort. The evidence of proteinuria and nephrotic syndrome prevalence in primary MN,  with lower PLA2r antigen positivity, underscore the importance of understanding MN's heterogeneity. These findings contribute to the broader understanding of MN's clinical spectrum and may inform regionally tailored management strategies.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.