Cost, resource utilization, and severity of illness in intensive care.

The relationship between health care resource use and severity of illness is important to hospitals providing care to sicker patients, so we investigated the relationship between resource utilization, cost, and severity of illness in 229 consecutive patients admitted to a pediatric intensive care unit. Resources measured included length of stay and number and cost of laboratory and imaging studies. Pediatric intensive care unit and daily mortality risks (assessed by the Physiologic Stability Index and the Dynamic Risk Index) were stratified as very low risk (less than 1%), low risk (1% to 2.5%), moderate risk (2.5% to 5.0%), and high risk (greater than 5%). Increasing daily resource use was directly related to increasing gradations of severity of illness. For very low, low-, moderate-, and high-risk patient days, the daily numbers of diagnostic studies were (mean +/- SEM) 20.1 +/- 0.6, 31.4 +/- 1.1, 37.7 +/- 1.6, and 43.0 +/- 1.8, respectively. Total resource use, including diagnostic tests and length of stay, also increased with pediatric intensive care unit mortality risk. Diagnostic testing and corresponding costs were significantly higher for infants who died in the pediatric intensive care unit than for survivors on a day-by-day basis as well as for the entire stay in the care unit. We conclude that there is a direct, positive relationship between resource use, cost, and gradations of severity of illness that, if accounted for, would result in more equitable health care reimbursement.