Whether continuous renal replacement therapy (CRRT) should be routinely initiated soon after severe acute kidney injury (AKI) in critically ill adults without urgent dialysis indications remains uncertain. We emulated a target trial using MIMIC-IV among adults in their first ICU stay who newly reached KDIGO stage 3 AKI by creatinine or urine-output criteria, had no prespecified urgent dialysis indication at time zero, and remained alive and in the ICU at 24 h. We compared CRRT initiation within 24 h with initial observation during that window, allowing delayed or rescue CRRT after the landmark. Among 4,538 eligible patients, 275 (6.1%) initiated CRRT within 24 h; among the 4,263 who did not, 419 (9.8%) subsequently received delayed/rescue CRRT. After multiple imputation and overlap weighting, CRRT initiation within 24 h was associated with higher 28-day post-landmark mortality (risk difference, 0.079; 95% CI, 0.014 to 0.145) and shorter restricted mean survival time (difference, -1.666 days; 95% CI, -3.247 to -0.179). The 12-hour analysis was directionally consistent but less precise. These findings do not support a default CRRT strategy based on stage 3 AKI alone, although residual confounding remains possible.
Liu et al. (Wed,) studied this question.