Spondyloarthritis-Associated IgA Nephropathy
N. Champtiaux, Frédéric Lioté, Khalil El Karoui, Cécile Vigneau, Corinne Miceli‐Richard, Émilie Cornec-Le Gall, Philippe Rémy, Gabriel Choukroun, Fádi Fakhouri, Cyril Garrouste, Laurent Veillon, Évangéline Pillebout, Thierry Lobbedez, Vincent Vuiblet, Alain Wynckel, Thomas Guincestre, Éric Toussirot, Éric Thervet, Marion Rabant, Alexandre Karras
Abstract
IntroductionIgA nephropathy (IgAN) can be associated with spondyloarthritis (SpA). The course of SpA-associated IgAN remains largely unknown due to the absence of large cohorts.MethodsThis retrospective study included patients with biopsy-proven IgAN and definite SpA. Kidney biopsies were centrally examined and scored according to the IgAN Oxford Classification. Thirty-two patients fulfilled the inclusion criteria, with a male:female ratio of 9:1 and median age of 27 and 37 years at SpA and IgAN diagnosis, respectively. HLA-B27 was positive in 90% of cases, and most patients (60%) presented with ankylosing spondylitis. The mean baseline estimated glomerular filtration rate (eGFR) was 84 ± 26 ml/min per 1.73 m2, and the urine protein-to-creatinine ratio was 0.19 g/mmol.ResultsRenal biopsy revealed frequent presence of crescents (33%) and interstitial inflammation (18%). Despite almost constant use of renin-angiotensin system inhibitors, combined with steroids in 13 of 32 patients, renal outcome was particularly poor. After a median follow-up of 5.9 years, 4 patients (12.5%) reached end-stage renal disease and 41% of patients experienced a >50% decrease of eGFR. The mean annual eGFR decline rate was −4.3 ± 6.7 ml/min per 1.73 m2. The risk of reaching class IV or V chronic kidney disease (CKD) stage during follow-up was associated with the presence of hypertension, level of proteinuria, and baseline S- and T-scores of the Oxford.ConclusionSpA-associated IgAN is associated with a poor renal outcome, despite frequent use of steroids. Tumor necrosis factor (TNF)-α blockade did not appear to influence the rate of eGFR decline in this setting.