Impact of nosocomial infection on cost of illness and length of stay in intensive care units.

OBJECTIVE: Economic evaluation has become increasingly important in healthcare and infection control. This study evaluated the impact of nosocomial infections on cost of illness and length of stay (LOS) in intensive care units (ICUs). DESIGN: A retrospective cohort study. SETTING: Medical, surgical, and mixed medical and surgical ICUs in a tertiary-care referral medical center. PATIENTS: Patients admitted to adult ICUs between October 2001 and June 2002 were eligible for the study. METHODS: Estimates of the cost and LOS for patients who acquired a nosocomial infection were computed using a stratified analysis and regression approach. RESULTS: During the study period, 778 patients were admitted to the ICUs. Total costs for patients with and without nosocomial infections (median cost, 10,354 dollars and 3985 dollars, respectively) were significantly different (P < .05). The costs stratified by infection site (median differences from 4687 dollars to 7365 dollars) and primary diagnosis (median differences from 5585 dollars to 16,507 dollars) were also significantly different (P < .05) except for surgical-site infection. After covariates were adjusted for in the multiple linear regression, nosocomial infection increased the total costs by 3306 dollars per patient and increased the LOS by 18.2 days per patient (P < .001). Each additional day spent in the ICU increased the cost per patient by 353 dollars (P < .001). CONCLUSIONS: Nosocomial infections are associated with increased cost of illness and LOS. Prevention of nosocomial infections should reduce direct costs and decrease the LOS.