Clinical variables associated with poor outcome from sepsis-associated acute kidney injury and the relationship with timing of initiation of renal replacement therapy

Abstract

Purpose: Identify clinical variables associated with mortality in patients with sepsis-associated acute kidney injury (SA-AKI) receiving continuous renal replacement therapy (CRRT) and examine timing of initiation of CRRT in reference to those variables identified.

Methods: Retrospective study conducted at two tertiary care hospitals including 939 septic shock patients with SA-AKI who received CRRT in the intensive care unit (ICU). Cox regression models were used to identify variables associated with 90-day mortality. Timing of CRRT initiation was assessed in relationship to significant clinical variables identified.

Results: Overall 90-day mortality was 62.9%. Variables prior to CRRT associated with 90-day mortality included: age (aHR, 1.02; 95%CI, 1.01-1.02, p<000.1), APS-III score (1.01, 1.0-1.0, p<0.048), days from hospital admission to CRRT initiation (1.01, 1.0-1.0, p<0.01), blood urea nitrogen (1.01, 1.0-1.0, p<0.04), medical admission (1.76, 1.5-2.1, p<0.0001), creatinine (0.99, 0.9-1.0, p<0.001), and urine output (0.77, 0.6-0.9, p=0.049). In patients with advanced SA-AKI at ICU admission receiving CRRT within the first 5days (n=433), urine output during the 24h prior to CRRT initiation was a strong predictor of survival (2.6, 1.6-4.3, p<0.001).

Conclusions: In patients with SA-AKI, survival is lower when CRRT is started in the setting of low urine output.

Keywords: Acute kidney injury; Continuous renal replacement therapy; Sepsis; Septic shock; Timing; Urine output.