Prognostic value of the MEST-C score in long-term outcomes of immunoglobulin A nephropathy patients: Insights from a developing country

Abstract

BACKGROUND

Immunoglobulin A nephropathy is a leading cause of primary glomerulonephritis globally. Predicting disease progression using clinical markers alone is often inadequate. Integrating the Oxford classification may enhance kidney survival predictions, though its relevance in Pakistan remains unexplored.

AIM

To determine the correlation between MEST-C scores and clinical parameters, as well as their utility in predicting long-term kidney outcomes.

METHODS

A retrospective analysis was conducted on biopsy-confirmed immunoglobulin A nephropathy cases diagnosed from 1998 to 2019 at the Sindh Institute of Urology and Transplantation, with a minimum follow-up of 12 months.

RESULTS

Among 118 patients (mean age: 29.03 ± 10.58 years), median proteinuria was 2.13 g/day, and mean estimated glomerular filtration rate (eGFR) was 67.82 ± 44.60 mL/minute/1.73 m². Upon admission, 26.4% required kidney replacement therapy. Oxford classification components (E1, T1/T2, C1/C2) were significantly linked to proteinuria and eGFR decline (P = 0.00). Remission rates were 79.6%, 77.9%, 77.1%, 49.3%, and 33.3% at 6 months, and at 1 year, 2 years, 5 years, and 10 years, respectively. End-stage kidney disease progression increased over time, reaching 20.3%, 22%, 22.8%, 31.3%, and 33.8% at 6 months, 1 year, 2 years, 5 years, and 10 years, respectively. Three (2.5%) patients died. The median follow-up was 3.5 years; kidney survival rates were 79.6%, 77.9%, 77.1%, 49.3% and 33.3% at 6 months and at 1 year, 2 years, 5 years, and 10 years, respectively. Higher MEST-C scores and lower baseline eGFR were associated with poorer kidney survival (log-rank P = 0.00), while no significant correlation was observed with the degree of proteinuria (log-rank P = 0.26).

CONCLUSION

The E1, T1/2, and C1/C2 components of the MEST-C score showed strong correlations with baseline clinical markers. Delayed diagnosis has led to poor long-term kidney outcomes.

Keywords: Estimated glomerular filtration rate; End-stage kidney disease; Immunoglobulin A nephropathy; Kidney replacement therapy; MEST-C

Core Tip: This study highlights the prognostic significance of the Oxford MEST-C score classification in immunoglobulin A nephropathy patients in Pakistan. Among 118 biopsy-confirmed cases, higher MEST-C scores - particularly E1, T1/2, and C1/C2 lesions - correlated with worse clinical parameters like proteinuria and estimated glomerular filtration rate, and predicted poor kidney survival. Remission rates declined, and end-stage kidney disease rates increased over time, with only 33.3% kidney survival at 10 years. These findings emphasize the value of integrating histopathological scoring with clinical data for early risk stratification. Delayed diagnosis contributed to adverse outcomes, underscoring the need for timely recognition and intervention in immunoglobulin A nephropathy management.