Identifying patients at increased risk for unplanned readmission

Abstract

Background: Reducing readmissions is a national priority, but many hospitals lack practical tools to identify patients at increased risk of unplanned readmission.

Objective: To estimate the association between a composite measure of patient condition at discharge, the Rothman Index (RI), and unplanned readmission within 30 days of discharge.

Subjects: Adult medical and surgical patients in a major teaching hospital in 2011.

Measures: The RI is a composite measure updated regularly from the electronic medical record based on changes in vital signs, nursing assessments, Braden score, cardiac rhythms, and laboratory test results. We developed 4 categories of RI and tested its association with readmission within 30 days, using logistic regression, adjusted for patient age, sex, insurance status, service assignment (medical or surgical), and primary discharge diagnosis.

Results: Sixteen percent of the sample patients (N=2730) had an unplanned readmission within 30 days of discharge. The risk of readmission for a patient in the highest risk category (RI<70) was >1 in 5 while the risk of readmission for patients in the lowest risk category was about 1 in 10. In multivariable analysis, patients with an RI<70 (the highest risk category) or 70-79 (medium risk category) had 2.65 (95% confidence interval, 1.72-4.07) and 2.40 (95% confidence interval, 1.57-3.67) times higher odds of unplanned readmission, respectively, compared with patients in the lowest risk category.

Conclusion: Clinicians can use the RI to help target hospital programs and supports to patients at highest risk of readmission.

Figure 1. Observed unplanned readmission rate by RI decile in full sample (N=5,511)¹

¹The solid line represents the observed readmission rate for each RI decile, and the dotted lines indicate the corresponding 95% confidence intervals for each decile. the x-axis shows the observed range of RI for each decile.

Figure 2. Observed and predicted unplanned readmission rates using Rothman Index (RI) in 4 categories, using validation data set (N=2,730)¹

¹Observed line is for RI deciles with confidence intervals for each decile; predicted line is for RI measured with 4 categories of risk. The x-axis shows the observed full range of RI.