Acuity scores as predictors of cost-related outcomes of neonatal intensive care

The Medicus Patient Classification System (PCS) and the lameter Acuity Index Method (AIM) are two proprietary scoring systems in common use for stratifying patient populations before making comparisons of the medical care they receive. In this study the validities of these scores were tested when the scores were used to evaluate cost-related elements of high-risk neonatal intensive care.

A total of 687 surviving inborn infants cared for in a university hospital newborn intensive care unit provided data for these analyses. The infants were stratified into the five diagnosis-related groups (DRGs) for surviving neonates (386, 387, 388, 389, and 390), as determined from their discharge diagnoses. Each infant's summed total of daily PCS scores, a single AIM score, and birth weight were extracted from the hospital's decision-support data files and used as independent variables in regression analyses to determine correlations with lengths of hospital stay, ancillary resource utilizations, and hospital charges.

The Medicus scores, which are computed prospectively on a daily basis, when summed retrospectively, correlated highly with lengths of stay, ancillary resource utilization, and associated hospital charges. The lameter scores, which are assigned retrospectively, were far less predictive of these outcome variables and generally worse than birth weight in explaining outcome variances.

Although in common use, the lameter AIM could not be validated as an appropriate method for assessing cost-related outcomes after newborn intensive care. The Medicus PCS produced daily scores that, when summed after patient discharge, correlated highly with the same outcome variables. There is a need to test further these and other proprietary methods now used to compare the cost-related elements of care provided by different hospitals and physicians.