Abstract: PO1842
IgA Nephropathy: Quantifying Remission Duration on Clinical Outcome
Session Information
- Glomerular Diseases: Clinical, Outcomes, and Trials - 1
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1203 Glomerular Diseases: Clinical, Outcomes, and Trials
Authors
- Canney, Mark, The University of British Columbia, Vancouver, British Columbia, Canada
- Barbour, Sean, The University of British Columbia, Vancouver, British Columbia, Canada
- Zheng, Yuyan, BC Provincial Renal Agency, Vancouver, British Columbia, Canada
- Coppo, Rosanna, Fondazione Ricerca Molinette, Torino, Piemonte, Italy
- Zhang, Hong, Peking University, Beijing, Beijing, China
- Liu, Zhihong, Nanjing University, Nanjing, Jiangsu, China
- Matsuzaki, Keiichi, Juntendo University, Bunkyo-ku, Tokyo, Japan
- Suzuki, Yusuke, Juntendo University, Bunkyo-ku, Tokyo, Japan
- Katafuchi, Ritsuko, Fukuoka Higashi Medical Center, Koga, Fukuoka, Japan
- Reich, Heather N., Toronto General Hospital, Toronto, Ontario, Canada
- Cattran, Daniel C., Toronto General Hospital, Toronto, Ontario, Canada
Group or Team Name
- The International IgA Nephropathy Network
Background
A relative reduction in proteinuria has been proposed as a surrogate outcome for therapeutic trials in IgA nephropathy (IgAN). We sought to quantify the association between duration of proteinuria remission and the risk of disease progression in IgAN.
Methods
In this retrospective international cohort of adult patients with biopsy-proven IgAN, we defined remission based on: (i) a ≥25% reduction in proteinuria from the peak value after biopsy; (ii) an absolute reduction in proteinuria to <1g/day; (iii) peak proteinuria prior to remission ≥1g/day. The total duration of first remission was treated as a time-varying exposure using longitudinal proteinuria measurements. Time-dependent Cox proportional hazards models were used to quantify the association between duration of remission and the primary outcome (ESKD or 50% reduction in eGFR).
Results
Of 1864 patients who entered a first remission, 274 (14.7%) experienced the outcome during median follow-up of 3.9 years. The relationship between duration of proteinuria remission and the primary outcome was non-linear (Figure). Each 3 months in sustained remission up to 51 months was associated with an additional 9% reduction in the risk of disease progression (HR 0.91, 95% CI 0.89-0.93). Each additional 3 months in remission beyond 51 months was associated with a non-significant risk reduction (HR 0.99, 95% CI 0.96-1.03). Results were robust to multivariable adjustment and consistent across subgroups including immunosuppression exposure.
Conclusion
We observed a non-linear dose-response relationship between the duration of proteinuria remission and the risk of disease progression in IgAN. When considering proteinuria as a surrogate outcome, our findings illustrate the need to consider the duration of remission in addition to the magnitude of proteinuria reduction when evaluating the anticipated impact on long-term clinical endpoints.