IgA Nephropathy in Elderly Patients

Abstract

Background and objectives: Some studies suggest that the incidence of IgA nephropathy is increasing in older adults, but there is a lack of information about the epidemiology and behavior of the disease in that age group.

Design, setting, participants, & measurements: In this retrospective multicentric study, we analyzed the incidence, forms of presentation, clinical and histologic characteristics, treatments received, and outcomes in a cohort of 151 patients ≥65 years old with biopsy-proven IgA nephropathy diagnosed between 1990 and 2015. The main outcome was a composite end point of kidney replacement therapy or death before kidney replacement therapy.

Results: We found a significant increase in the diagnosis of IgA nephropathy over time from six patients in 1990-1995 to 62 in 2011-2015 (P value for trend =0.03). After asymptomatic urinary abnormalities (84 patients; 55%), AKI was the most common form of presentation (61 patients; 40%). Within the latter, 53 (86%) patients presented with hematuria-related AKI (gross hematuria and tubular necrosis associated with erythrocyte casts as the most important lesions in kidney biopsy), and eight patients presented with crescentic IgA nephropathy. Six (4%) patients presented with nephrotic syndrome. Among hematuria-related AKI, 18 (34%) patients were receiving oral anticoagulants, and this proportion rose to 42% among the 34 patients older than 72 years old who presented with hematuria-related AKI. For the whole cohort, survival rates without the composite end point were 74%, 48%, and 26% at 1, 2, and 5 years, respectively. Age, serum creatinine at presentation, and the degree of interstitial fibrosis in kidney biopsy were risk factors significantly associated with the outcome, whereas treatment with renin-angiotensin-aldosterone blockers was associated with a lower risk. Immunosuppressive treatments were not significantly associated with the outcome.

Conclusions: The diagnosis of IgA nephropathy among older adults in Spain has progressively increased in recent years, and anticoagulant therapy may be partially responsible for this trend. Prognosis was poor.

Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_07_16_CJASNPodcast_19_08_.mp3.

Keywords: Angiotensins; Anticoagulants; Biopsy; Erythrocytes; Glomerulonephritis, IGA; Hematuria; IgA nephropathy; Incidence; Kidney Function Tests; Prognosis; Renal Replacement Therapy; Renin; Retrospective Studies; acute kidney injury; acute renal failure; aldosterone; anticoagulation therapy; creatinine; hematuria; nephrotic syndrome; risk factors.

Graphical abstract

Figure 1.

Clinical presentation of biopsy-diagnosed IgA nephropathy among older adults over time.

Figure 2.

Survival without kidney replacement therapy according to clinical presentation. Crescentic AKI (C-AKI) versus asymptomatic urinary abnormality (AUA): P=0.03. Composite outcome definition: kidney replacement therapy or death before kidney replacement therapy. HR-AKI, hematuria-related AKI; NS, nephrotic syndrome.

Figure 3.

Survival without kidney replacement therapy by treatment received after diagnosis. (A) Patients with asymptomatic urinary symptoms according to immunosuppressive treatment. Dotted line indicates immunosuppressive therapy. Solid line indicates no immunosuppressive therapy. (B) Patients with asymptomatic urinary symptoms according to renin-angiotensin-aldosterone system inhibitors. Dotted line indicates renin-angiotensin-aldosterone system inhibitors. Solid line indicates no renin-angiotensin-aldosterone system inhibitors (C) Patients with hematuria-related AKI according to immunosuppressive treatment. Dotted line indicates immunosuppressive therapy. Solid line indicates no immunosuppressive therapy.