Long-term outcomes of patients with IgA nephropathy in the German CKD cohort
Author:
Stamellou Eleni12ORCID, Nadal Jennifer3, Hendry Bruce4, Mercer Alex5, Seikrit Claudia1, Bechtel-Walz Wibke67, Schmid Matthias3, Moeller Marcus J1, Schiffer Mario8, Eckardt Kai-Uwe89ORCID, Kramann Rafael1ORCID, Floege Jürgen110, , Eckardt Kai-Uwe, Meiselbach Heike, Schneider Markus P, Schiffer Mario, Prokosch Hans-Ulrich, Bärthlein Barbara, Beck Andreas, Reis André, Ekici Arif B, Becker Susanne, Alberth-Schmidt Ulrike, Marschall Sabine, Weigel Anke, Walz Gerd, Köttgen Anna, Schultheiß Ulla T, Kotsis Fruzsina, Meder Simone, Mitsch Erna, Reinhard Ursula, Floege Jürgen, Saritas Turgay, Schaeffner Elke, Baid-Agrawal Seema, Theisen Kerstin, Schmidt-Ott Kai, Zeier Martin, Sommerer Claudia, Aykac Mehtap, Wolf Gunter, Busch Martin, Steiner Andi, Sitter Thomas, Wanner Christoph, Krane Vera, Bauer Britta, Kronenberg Florian, Raschenberger Julia, Kollerits Barbara, Forer Lukas, Schönherr Sebastian, Weissensteiner Hansi, Oefner Peter, Gronwald Wolfram, Schmid Matthias, Nadal Jennifer
Affiliation:
1. Division of Nephrology and Clinical Immunology, RWTH Aachen University Hospital , Aachen , Germany 2. Department of Nephrology, School of Medicine, University of Ioannina , Ioannina , Greece 3. Department of Medical Biometry, Informatics and Epidemiology, Faculty of Medicine, University Hospital Bonn , Bonn , Germany 4. Travere Therapeutics , San Diego, CA , USA 5. JAMCO Pharma Consulting , Stockholm , Sweden 6. Department of Medicine IV, University Medical Center, Faculty of Medicine, University of Freiburg , Freiburg , Germany 7. Berta-Ottenstein Program, Faculty of Medicine, University of Freiburg , Freiburg , Germany 8. Department of Nephrology and Hypertension, Friedrich-Alexander-Universität Erlangen-Nürnberg , Erlangen , Germany 9. Department of Nephrology and Medical Intensive Care, Charité – Universitätsmedizin Berlin , Berlin , Germany 10. Department of Cardiology, RWTH Aachen University Hospital , Aachen , Germany
Abstract
ABSTRACT
Background
The importance of albuminuria as opposed to proteinuria in predicting kidney outcomes in primary immunoglobulin A nephropathy (IgAN) is not well established.
Methods
From 2010 to 2012, 421 patients with biopsy-proven IgAN have been enrolled into the German Chronic Kidney Disease (GCKD) cohort, a prospective observational cohort study (N = 5217). Adjudicated endpoints include a composite kidney endpoint (CKE) consisting of eGFR decline >40%, eGFR <15 ml/min/1.73 m2 and initiation of kidney replacement therapy; the individual components of the CKE; and combined major adverse cardiac events (MACE), including non-fatal myocardial infarction, non-fatal stroke and all-cause mortality. The associations between the incidence of CKE and baseline factors, including demographics, laboratory values and comorbidities were analysed using the Cox proportional hazards regression model.
Results
The mean age of IgAN patients at baseline was 51.6 years (± 13.6) and 67% were male. The patient-reported duration of disease at baseline was 5.9 ± 8.1 years. Baseline median urine albumin:creatinine ratio (UACR) was 0.4 g/g [interquartile range (IQR) 0.1–0.8] and mean eGFR was 52.5 ± 22.4 ml/min/1.73 m2. Over a follow-up of 6.5 years, 64 (15.2%) patients experienced a >40% eGFR decline, 3 (0.7%) reached eGFR <15 ml/min/1.73 m2, 53 (12.6%) initiated kidney replacement therapy and 28% of the patients experienced the CKE. Albuminuria, with reference to <0.1 g/g, was most associated with CKE. Hazard ratios (HRs) at UACRs of 0.1–0.6 g/g, 0.6–1.4 g/g, 1.4–2.2 g/g and >2.2 g/g were 2.03 [95% confidence interval (CI) 1.02–4.05], 3.8 (95% CI 1.92–7.5), 5.64 (95% CI 2.58–12.33) and 5.02 (95% CI 2.29–11-03), respectively. Regarding MACE, the presence of diabetes [HR 2.53 (95% CI 1.11–5.78)] was the most strongly associated factor, whereas UACR and eGFR did not show significant associations.
Conclusion
In the GCKD IgAN subcohort, more than every fourth patient experienced a CKE event within 6.5 years. Our findings support the use of albuminuria as a surrogate to assess the risk of poor kidney outcomes.
Funder
Deutsche Forschungsgemeinschaft
Publisher
Oxford University Press (OUP)
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