Clinical and Prognostic Factors in Patients with IgG4-Related Kidney Disease
Anis Chaba, Arnaud Devresse, Vincent Audard, J.J. Boffa, Alexandre Karras, C. Cartery, Clément Deltombe, Jonathan Chemouny, Claudine Contamin, Cécile Courivaud, Simon Duquennoy, Hugo García, Dominique Joly, N. Goumri, Guillaume Hanouna, Jean‐Michel Halimi, Emmanuelle Plaisier, M. Hamidou, C. Landron, David Launay, Céline Lebas, Mathieu Legendre, A. Masseau, Alexis Mathian, Lucile Mercadal, Nathalie Morel, P. Mutinelli-Szymanski, S. Palat, Jean‐Loup Pennaforte, M.N. Peraldi, Agnieszka Pozdzik, N. Schleinitz, Olivier Thaunat, Dimitri Titeca‐Beauport, Charlotte Mussini, S Touati, Éric Prinz, Anne Laure Faller, Sarah Richter, Éve Vilaine, Sophie Ferlicot, Clarissa Von-Kotze, Julie Bellière, Jérôme Olagne, Rafik Mesbah, Renaud Snanoudj, M. Nouvier, Mikaël Ebbo, Mohamad Zaidan
Abstract
BACKGROUND: IgG4-related kidney disease is a major manifestation of IgG4-related disease, a systemic fibroinflammatory disorder. However, the clinical and prognostic kidney-related factors in patients with IgG4-related kidney disease are insufficiently defined. METHODS: We conducted an observational cohort study using data from 35 sites in two European countries. Clinical, biologic, imaging, and histopathologic data; treatment modalities; and outcomes were collected from medical records. Logistic regression was performed to identify the possible factors related to an eGFR ≤30 ml/min per 1.73 m 2 at the last follow-up. Cox proportional hazards model was performed to assess the factors associated with the risk of relapse. RESULTS: We studied 101 adult patients with IgG4-related disease with a median follow-up of 24 (11-58) months. Of these, 87 (86%) patients were male, and the median age was 68 (57-76) years. Eighty-three (82%) patients had IgG4-related kidney disease confirmed by kidney biopsy, with all biopsies showing tubulointerstitial involvement and 16 showing glomerular lesions. Ninety (89%) patients were treated with corticosteroids, and 18 (18%) patients received rituximab as first-line therapy. At the last follow-up, the eGFR was below 30 ml/min per 1.73 m 2 in 32% of patients; 34 (34%) patients experienced a relapse, while 12 (13%) patients had died. By Cox survival analysis, the number of organs involved (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.01 to 1.55) and low C3 and C4 concentrations (HR, 2.31; 95% CI, 1.10 to 4.85) were independently associated with a higher risk of relapse, whereas first-line therapy with rituximab was protective (HR, 0.22; 95% CI, 0.06 to 0.78). At their last follow-up, 19 (19%) patients had an eGFR ≤30 ml/min per 1.73 m 2 . Age (odd ratio [OR], 1.11; 95% CI, 1.03 to 1.20), peak serum creatinine (OR, 2.74; 95% CI, 1.71 to 5.47), and serum IgG4 level ≥5 g/L (OR, 4.46; 95% CI, 1.23 to 19.40) were independently predictive for severe CKD. CONCLUSIONS: IgG4-related kidney disease predominantly affected middle-aged men and manifested as tubulointerstitial nephritis with potential glomerular involvement. Complement consumption and the number of organs involved were associated with a higher relapse rate, whereas first-line therapy with rituximab was associated with lower relapse rate. Patients with high serum IgG4 concentrations (≥5 g/L) had more severe kidney disease.