#1638 Long-term mortality trends in IgA nephropathy: a study of an Eastern European cohort
Authors: Stefan Gabriel , Zugravu Adrian Dorin , Stancu Simona 
Published: May 2024

Abstract

Background and Aims
IgA Nephropathy (IgAN), recognized as the most prevalent form of primary glomerulonephritis, has been thoroughly researched in terms of renal outcomes. However, there is a scarcity of data regarding patient survival, especially in Eastern Europe. Our study focuses on exploring the long-term survival rates of IgAN patients and identifying associated risk factors within an Eastern European population.

Method
In our retrospective study, we analyzed 215 patients with biopsy proven IgAN (median age 44 years, 71% male, median eGFR 40.9 mL/min/1.73 m2, median proteinuria 1.24g/g) diagnosed at a tertiary center in Romania from 2010 to 2017. Our study primarily focused on all-cause mortality and secondarily on the development of ESKD (start of kidney replacement therapy or renal transplantation). The follow-up for patients continued until they reached either of these endpoints or until January 1, 2022, whichever came first.

Results
During a median follow-up of 7.3 years, 20% of the patients died. The main causes of death were cardiovascular diseases (60%), followed by infectious (19%), gastroenterological (12%), and neoplasia (9%) diseases.
Mean survival of the entire cohort was 117.5 months (95% CI: 111.2, 123.8) and mean kidney survival was 98.4 months (95% CI: 90.5, 106.2). Survival rates at 1 year, 5 years and 10 years were 93%, 84% and 77% respectively, and kidney survival rates at 1 year, 5 years and 10 years were 87%, 72% and 58% respectively.
When compared to the survivors, deceased patients were significantly older (60 vs 42 years, p 0.001) and had an increased prevalence of diabetes mellitus (26 vs 4%, p 0.001) and higher Charlson comorbidity index (5 vs 2, p 0.001). Deceased patients also had significantly higher serum creatinine levels (3.3 vs 1.6 mg/dL, p 0.001), lower eGFR (18 vs 46 mL/min, p 0.001), and more haematuria (230 vs 183cells/HPF, p 0.01). There was no significant difference in proteinuria between the two groups (1.1 vs 1.2g/g, p 0.3).
In the univariate Cox regression analysis, all-cause mortality was significantly associated with several factors: advancing age (HR 1.08, 95% CI: 1.05, 1.11), an increased Charlson comorbidity index (HR 1.60, 95% CI: 1.42, 1.80), the presence of diabetes mellitus (HR 5.13, 95% CI: 2.57, 10.25), lower eGFR (HR 0.95, 95% CI: 0.93, 0.97), increased proteinuria (HR 1.12, 95% CI: 1.00, 1.25), the presence of haematuria (HR 1.26, 95% CI: 1.03, 1.53), lower serum albumin (HR 0.35, 95% CI: 0.22, 0.56), higher MEST-C score (HR 1.38, 95% CI 1.13, 1.69) and absence of renin-angiotensin-system inhibitors (RASI) (HR 0.32, 95% CI 0.17, 0.60). However, in the multivariate analysis, only an increased Charlson comorbidity index (HR 1.31, 95% CI: 1.09, 1.57), lower eGFR (HR 0.98, 95% CI: 0.96-1.00) and absence of RASI (HR 0.21, 95% CI: 0.15, 0.28) retained their statistical significance.

Conclusion
We report a 20% mortality rate in our Eastern European IgAN cohort, primarily due to cardio-vascular diseases. Death correlates with increased age, comorbidity burden, decreased renal function at diagnosis, and absence of RASI use. RASI treatment may potentially improve survival, highlighting its importance in managing IgAN.