IgA Nephropathy in the Elderly

Abstract

Introduction

Knowledge about IgA nephropathy (IgAN) presentation and prognosis for elderly patients is limited. We assessed clinical and histologic findings among patients aged ≥ 60 years at diagnosis and examined factors associated with the risk of kidney failure and death.

Methods

We identified those patients at our center between 1996 and 2020. Age, sex, race, chronic kidney disease (CKD) stage, and histologic MEST-C classification at biopsy were collected. Outcomes of kidney failure and death were ascertained by using United States Renal Data System (USRDS) and National Death Index (NDI), respectively. Associations of baseline predictors with kidney failure were examined by using cause-specific Cox hazards regression with all-cause mortality as competing risk. For all-cause mortality, standard Cox proportional hazards regression analysis was used. Cumulative survival probabilities were examined using Kaplan-Meier survival curves.

Results

Among 127 patients, median estimated glomerular filtration rate (eGFR) was 25 ml/min per 1.73 m², 81% had proteinuria ≥ 1000 mg/g creatinine, 35% and 17% had CKD stages 4 and 5, respectively. Forty-five patients progressed to kidney failure and 86 died. Overall, Kaplan-Meier estimate of median time to kidney failure was 11.3 years and to death was 7.5 years. Males were more likely to progress to kidney failure than females. Kidney failure strongly associated with CKD stages 3, 4, and 5 versus stages 1 or 2; findings remained unchanged after adjusting for histology. Mortality was associated with increasing age and advanced CKD.

Conclusion

IgAN diagnosed at elderly age is associated with severe clinical phenotype and portends a poor prognosis because of high risk of kidney failure and death.