Change in platelet and leukocyte counts and hospital mortality in adults with acute kidney injury receiving continuous renal replacement therapy.

BACKGROUND

Changes in platelet and white blood cell (WBC) counts during CRRT could identify patients at risk for adverse outcomes. We examined the association of change in platelet and WBC from pre-CRRT to during-CRRT with hospital mortality.

METHODS

This multicenter, retrospective cohort study included 1,413 adults with AKI requiring CRRT at two tertiary medical centers (2011-2021). Platelet and WBC change from pre- to during CRRT were assessed as a percentage and categorized by standard deviation (SD). Multivariable LASSO regression and interaction analyses investigated associations with hospital mortality.

RESULTS

A > 1 SD platelet count drop during CRRT was independently associated with hospital mortality (aOR: 1.82, 95% CI: 1.06, 3.13). A > 1 SD WBC count increase during CRRT did not significantly increase mortality (aOR 1.41, 95% CI: 0.88, 2.29). Interaction analyses revealed four sub-groups associated with increased mortality: pre-CRRT low platelet count that remained low, pre-CRRT normal platelet count that decreased, pre-CRRT elevated WBC count that remained high, and normal or elevated pre-CRRT WBC count that increased.

INTERPRETATION: In critically ill adults, a drop in platelets after CRRT initiation was associated with increased hospital mortality. Monitoring platelet and WBC during CRRT in reference to pre-CRRT levels could help identify high-risk patients.