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Abstract #149624
Audio (mp3) recordingDavid E. Clark, MD MPH1, Louise M. Ryan, PhD2, and F.L. Lucas, PhD1. (1) Center for Outcomes Research and Evaluation, Maine Medical Center, 887 Congress Street, Suite 210, Portland, ME 04102, 207-774-2381, clarkd@mmc.org, (2) Department of Biostatistics, Harvard School of Public Health, 655 Huntington Avenue, Boston, MA 02115
Background: To allow more accurate prediction of hospital length of stay (LOS) after serious injury, a multi-state model is proposed, in which transitions from the hospitalized state to three possible discharged states (home, long-term care, or death) are assumed to follow piecewise constant rates for each of a limited number of time periods. These rates may be affected differently by time-varying covariates, and result in a piecewise exponential model that can be estimated from a reference database using standard statistical software and Poisson regression. Methods: Records of 259,941 injured patients from the U.S. Nationwide Inpatient Sample were used to create a multi-state piecewise exponential model with four time periods. Hospital mortality and LOS for patient subgroups were calculated from this model, and time-varying covariate effects were estimated. Results: Early mortality was increased by anatomic injury severity or penetrating mechanism, but these effects diminished with time; age and male sex remained strong predictors of mortality in all time periods. Rates of discharge home decreased steadily with time, while rates of transfer to long-term care peaked at five days. Predicted and observed LOS and mortality were similar for multiple subgroups. Conclusions: Multi-state piecewise exponential models may be useful to describe hospital outcomes, especially after serious injuries or other conditions when many patients are not discharged home.
Learning Objectives:
- Recognize limitations of hospital mortality and LOS as outcome measurements.
- Understand an innovative method for estimating covariate effects on these outcomes.
Keywords: Hospitals, Outcome Measures
Presenting author's disclosure statement:
Any relevant financial relationships? No
Any institutionally-contracted trials related to this submission?
I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.
The 135th APHA Annual Meeting & Exposition (November 3-7, 2007) of APHA