Objective: Evidence suggests that patients requiring high-risk procedures benefit from care at institutions providing a large volume of these procedures. Our objective was to determine whether there is a volume-outcome relationship among intensive care unit patients receiving renal support therapy in two different healthcare systems (France and the United States).
Design: Retrospective cohort study.
Setting: Two multicenter intensive care unit databases: CUB-Réa (France) and Project IMPACT (United States).
Patients: All nonsurgical adults requiring renal support therapy from 1997 to 2007 were included.
Interventions: None.
Measurements and main results: We assessed association of annual renal support therapy volume with intensive care unit and hospital mortality using multivariable modeling, accounting for clustering and adjusting for age, comorbidities, admitting diagnosis, illness severity, pre-intensive care unit length of stay, admission source, and hospital and intensive care unit characteristics. Our final cohorts were 9,449 patients treated in 32 intensive care units in CUB-Réa and 3,498 patients treated in 76 intensive care units in Project IMPACT. Patient demographics did not differ between cohorts. Renal support therapy delivery varied widely across intensive care units (3-129 patients per year in CUB-Réa, 1-66 in Project IMPACT). Overall intensive care unit and hospital mortality rates were 45% and 49% in CUB-Réa and 34% and 47% in Project IMPACT. After adjustment for patient, intensive care unit, and hospital characteristics, there was no association between renal support therapy volume and intensive care unit or hospital mortality whether we treated volume as a continuous measure or quartiles. Higher renal support therapy volume was associated with shorter length of stay only in CUB-Réa.
Conclusions: There is a large variation in annual renal support therapy volume across intensive care units in France and the United States but no association of higher volumes with improved outcomes.