Predicting length of stay on an acute care medical psychiatric inpatient service.

The goal of this study was to identify variables associated with length of stay (LOS) and to incorporate into the authors' routine preadmission assessment the measurement of these variables. A retrospective study of 80 discharged patients explored the association of 25 variables reflecting a mixture of patient/demographic variables, illness variables, and treatment variables with LOS. Multivariate analysis revealed that 10 variables independently accounted for 62% of the variance in LOS. The information used was obtained primarily in the preadmission screening. The predictive power of the variables shrank in the prospective study. However, fewer individual variables were significantly associated with LOS; the summed score of the variables predicted 17% of the LOS variance. Results indicated that factors important for estimating LOS are available at the time of admission, and these variables can be systematically assessed and incorporated into clinical decision making.