Title

Functional Status Outperforms Comorbidities as a Predictor of 30-Day Acute Care Readmissions in the Inpatient Rehabilitation Population

Authors

Shirley Shih
Ross Zafonte
David Bates
Paul Gerrard
Richard Goldstein
Jacqueline Mix
Paulette Niewczyk, Daemen College
Ryan Greysen
Lewis Kazis
Colleen Ryan
Jeffrey Schneider

Department

Health Promotion

Document Type

Article

Publication Source

Journal of the American Medical Directors Association

Publication Date

2016-10

Volume

17

Issue

10

First Page

921

Last Page

926

Abstract

OBJECTIVES: Functional status is associated with patient outcomes, but is rarely included in hospital readmission risk models. The objective of this study was to determine whether functional status is a better predictor of 30-day acute care readmission than traditionally investigated variables including demographics and comorbidities.

DESIGN: Retrospective database analysis between 2002 and 2011.

SETTING: 1158 US inpatient rehabilitation facilities.

PARTICIPANTS: 4,199,002 inpatient rehabilitation facility admissions comprising patients from 16 impairment groups within the Uniform Data System for Medical Rehabilitation database.

MEASUREMENTS: Logistic regression models predicting 30-day readmission were developed based on age, gender, comorbidities (Elixhauser comorbidity index, Deyo-Charlson comorbidity index, and Medicare comorbidity tier system), and functional status [Functional Independence Measure (FIM)]. We hypothesized that (1) function-based models would outperform demographic- and comorbidity-based models and (2) the addition of demographic and comorbidity data would not significantly enhance function-based models. For each impairment group, Function Only Models were compared against Demographic-Comorbidity Models and Function Plus Models (Function-Demographic-Comorbidity Models). The primary outcome was 30-day readmission, and the primary measure of model performance was the c-statistic.

RESULTS: All-cause 30-day readmission rate from inpatient rehabilitation facilities to acute care hospitals was 9.87%. C-statistics for the Function Only Models were 0.64 to 0.70. For all 16 impairment groups, the Function Only Model demonstrated better c-statistics than the Demographic-Comorbidity Models (c-statistic difference: 0.03-0.12). The best-performing Function Plus Models exhibited negligible improvements in model performance compared to Function Only Models, with c-statistic improvements of only 0.01 to 0.05.

CONCLUSION: Readmissions are currently used as a marker of hospital performance, with recent financial penalties to hospitals for excessive readmissions. Function-based readmission models outperform models based only on demographics and comorbidities. Readmission risk models would benefit from the inclusion of functional status as a primary predictor.

Keywords

readmission, functional status, patient outcomes, rehabilitation

DOI

10.1016/j.jamda.2016.06.003

Recommended Citation

Shih, S., Zafonte, R., Bates, D., Gerrard, P., Goldstein, R., Mix, J., . . . Schneider, J. (2016). Functional Status Outperforms Comorbidities as a Predictor of 30-Day Acute Care Readmissions in the Inpatient Rehabilitation Population. Journal of the American Medical Directors Association, 17(10), 921-926. https://doi.org/10.1016/j.jamda.2016.06.003

https://linkinghub.elsevier.com/retrieve/pii/S1525-8610(16)30183-9