LONG-TERM KIDNEY FUNCTION BEYOND 12 MONTHS AND KIDNEY RELAPSE AFTER INITIATION OF TREATMENT FOR ANCA-ASSOCIATED VASCULITIS

Introduction:

Despite therapeutic advances, ANCA-associated vasculitis (AAV) still has substantial rates of end-stage kidney disease (ESKD). While previous analyses explored kidney function in AAV patients, long-term trajectories of estimated glomerular filtration rate (eGFR) and the influence of kidney relapse on progression of chronic kidney disease (CKD) are still not well elucidated. The aim of the study was to evaluate long-term kidney function before and after kidney relapses, and in participants who did not experience relapse, utilizing data from the PEXIVAS trial of plasma exchange and glucocorticoid dosing.

Methods:

This post-hoc analysis of the PEXIVAS trial included participants with kidney involvement at baseline who achieved remission prior to 12 months and had at least 2 subsequent eGFR assessments. Those with ESKD before 12 months were excluded. We calculated eGFR slopes of participants who did not experience renal relapse as well as pre-relapse and post-relapse slopes of participants who had renal relapse 12 months from randomization and after. We additionally compared the group mean eGFRs at each follow-up time. To create a common time to compare eGFR relative to the time of relapse, all participants were assigned a Time 0 defined as: 1. time of relapse for relapsers and 2. 30 months from randomization (the median time to relapse) for all non-relapsers. Mixed linear regression was used to assess eGFR slopes. We also investigated the potential for non-linearity and used piecewise regression to evaluate pre- and post-relapse slopes.

Results:

Of 704 participants in PEXIVAS, 459 were included, of whom 51 (11.1%) had kidney relapses after 12 months. Baseline characteristics were similar between those with and without kidney relapse including median eGFR at randomisation (17.2 vs. 19.2 ml/min/1.73 m2; p=0.76) and at 12 months (41.3 vs. 42.7 ml/min/1.73 m2; p=0.37) (Table 1). The median time to kidney relapse was 847 days from randomisation. The mean eGFR in those that relapsed was lower at and after relapse compared to those that did not relapse (Figure 1). Overall slope for non-relapsers was 1.08 (95%CI: -17.5 to 19.7) mL/min/1.73 m2/year while the pre-relapse slope for relapsers was -8.7 (95%CI: -17.6 to -0.05) mL/min/1.73 m2/year and post-relapse was -1.5 (95%CI: -16.9 to 20.0) mL/min/1.73 m2/year (p-value for comparison of pre- vs. post-relapse slope = 0.03).

Conclusions:

Kidney relapse in AAV occurring 12 months after initiation of treatment is associated with an antecedent decline in eGFR which has a lasting effect. Those with no relapse demonstrate a stable eGFR over time. Early identification and treatment of kidney relapses in AAV may improve long-term kidney function. 

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.