Epidemiology of augmented renal clearance in mixed ICU patients

Background. Augmented renal clearance (ARC) or renal hyperfiltration is increasingly reported in intensive care unit (ICU) patients. The goal of this analysis was to study the epidemiology of ARC in a cohort of mixed ICU patients Methods. Single center retrospective cohort study of adult ICU patients (12/2008-2/2010). When data were available, urinary creatinine clearance (CLCR) was calculated for all patients throughout their ICU stay. ARC was defined as a body surface adjusted CLCR >= 130 mL/min/1.73m(2). We sought to study the incidence of ARC and identify patient characteristics associated with ARC. Results. A total of 1081 patients were included in the analysis, generating 4472 ICU patient days. Median age was 62 y (IQR 50-72), and 63% were male. The initial CLCR was 86 (39-151) mL/min and the maximal CLCR was 145 (76-237) mL/min. ARC occurred in 55.8% of patients, and was about as frequent in men and women (37%% vs. 35%%, P=0.73). Patients with ARC were younger (57 vs. 67 years, P<0.001) and were less frequently treated with vasopressors (27% vs. 39%, P<0.01). ARC incidence was 36.6 ARC days per 100 ICU days. ARC throughout the ICU stay occurred in 32.8% of patients. Conclusion. ARC was a frequent finding in this cohort of ICU patients, with more than half of the patient expressing ARC at least once during their ICU stay, and an incidence of 36.6 ARC days/100 patient days.