Impact of using oral spherical carbon adsorbent in predialysis chronic kidney disease period on cardiovascular outcome after dialysis therapy

The oral spherical carbon adsorbent (OSCA), AST-120, has demonstrated efficacy in slowing the progression of chronic kidney disease (CKD). This study assessed the impact of OSCA administration during predialysis CKD period on cardiovascular outcomes after dialysis therapy. We conducted a retrospective cohort study with 294 patients, including 98 who received OSCA before dialysis (OSCA group) and 196 matched control by age and sex (control group). The primary outcome was cardiovascular events, and the secondary composite outcome included cardiovascular events and cardiovascular death post-dialysis initiation. The analysis of cardiovascular event-free survival revealed no difference between two groups (P = 0.228). However, when the OSCA group was further divided based on the duration of OSCA administration, the patients who received OSCA for ≥ 4 months presented significantly fewer cardiovascular events than those who received OSCA for shorter periods (P = 0.032). Multivariate Cox models revealed a reduced risk of cardiovascular events in the OSCA ≥ 4 months group compared to the control group (HR 0.39, 95% CI 0.18-0.84). Additionally, the OSCA ≥ 4 months group experienced significantly fewer composite outcome (HR 0.46, 95% CI 0.24-0.90). These findings indicate that longer-term OSCA use before dialysis initiation could reduce cardiovascular events and death post-dialysis, suggesting a potential 'legacy effect'.