Interhospital transfer and outcomes in patients with AKI: a population-based cohort study

Background — Patients with AKI may require interhospital transfer to receive RRT. Interhospital transfer may lead to delays in therapy, resulting in poor patient outcomes. There is minimal data comparing outcomes among patients undergoing transfer for RRT versus those who receive RRT at the hospital to which they first present.

Methods — We conducted a population-based cohort study of all adult patients (≥19 years) who received acute dialysis within 14 days of admission to an acute-care hospital between April 1, 2004 and March 31, 2015. The transferred group included all patients who presented to a hospital without a dialysis program and underwent interhospital transfer (with the start of dialysis ≤3 days of transfer and within 14 days of initial admission). All other patients were considered nontransferred. The primary outcome was time to 90-day all-cause mortality, adjusting for demographics, comorbidities, and measures of acute illness severity. We also assessed chronic dialysis dependence as a secondary outcome, using the Fine and Gray proportional hazards model to account for the competing risks of death. In a secondary post hoc analysis, we assessed these outcomes in a propensity score–matched cohort, matching on age, sex, and prior CKD status.

Results — We identified 27,270 individuals initiating acute RRT within 14 days of a hospital admission, of whom 2113 underwent interhospital transfer. Interhospital transfer was associated with lower rate of mortality (adjusted hazard ratio [aHR], 0.90; 95% CI, 0.84 to 0.97). Chronic dialysis dependence was not significantly different between groups (aHR, 0.98; 95% CI, 0.91 to 1.06). In the propensity score–matched analysis, interhospital transfer remained associated with a lower risk of death (HR, 0.88; 95% CI, 0.80 to 0.96).

Conclusions — Interhospital transfer for receipt of RRT does not confer higher mortality or worse kidney outcomes.