Data Sheet 1_Serum uric acid variability and short-term mortality in chronic kidney disease: a retrospective cohort study with independent replication in MIMIC-IV.docx

Inroduction<p>Within-person variation in serum uric acid (SUA) may reflect clinical instability, but its association with outcomes in chronic kidney disease (CKD) is uncertain.</p>Methods<p>We studied 10,556 adults with EHR-defined CKD and at least three SUA measurements during a 365-day baseline window across a nine-hospital consortium. Variability was quantified primarily by the coefficient of variation (CV); the primary outcome was all-cause mortality, and secondary outcomes were a composite kidney endpoint and major adverse cardiovascular events (MACE).

Cox models adjusted for demographics, comorbidities, baseline laboratory values, mean SUA, measurement number and medication use. Reproducibility of the short-term mortality association was assessed in MIMIC-IV.</p>Results<p>During a median follow-up of 0.62 years, 649 deaths, 676 kidney events and 3,172 first MACE occurred. Higher SUA CV was associated with mortality in the fully adjusted model (hazard ratio [HR] per 1-SD increase 1.24, 95% CI 1.15–1.32; highest versus lowest tertile 1.87, 95% CI 1.50–2.33), whereas adjusted associations with kidney events (HR 1.01, 95% CI 0.93–1.10) and MACE (HR 1.02, 95% CI 0.98–1.05) were null.