How Predictive Is the Rothman Index for TKA Readmission?

A new retrospective, multicenter study has investigated the use of the Rothman Index (PeraHealth, Charlotte, North Carolina), a predictive analytic measure that supplies real-time data on patient well-being, for predicting readmission or home discharge after total knee arthroplasty (TKA). This represents the first-ever study on the relationship among the Rothman Index and discharge location after TKA.

The study, “Do In-Hospital Rothman Index Scores Predict Postdischarge Adverse Events and Discharge Location After Total Knee Arthroplasty?” appears in the December 22, 2021 edition of the Journal of Arthroplasty.

Co-author Andrew D. Kleven, M.D., D.P.T., an orthopedic resident at the Medical College of Wisconsin in Milwaukee, stated to OTW, “In light of COVID-19 and the increasing emphasis on reducing length of stay and readmissions after joint replacement, this research study evaluated the potential benefit of a proprietary and objective tool that interfaces with the electronic medical record to help with discharge planning and identifying those patients at risk of readmission.”

Using an institutional database of elective, primary TKAs from July 2018 until December 2019, the researchers looked for complications and readmissions per the Centers for Medicare and Medicaid Services definitions.

Rothman Index scores range from 91 to 100, with 100 representing unimpaired and a lower score indicating a more severe condition. According to the authors, “The score is calculated from vital signs, laboratory values, nursing assessments, and cardiac rhythms and can be assigned to any inpatient. Due to its proprietary nature, the algorithm to calculate a score is unknown.”

Of the 957 procedures in the study, the researchers found 2.4% complications, 3.6% readmissions, and 13.7% non-home discharge.

They determined that all Rothman Index metrics (minimum, maximum, last, mean, range, 25th%, and 75th%) were significantly associated with increased odds of readmission and home discharge. Rothman Index scores were not significantly associated with complications. The authors wrote, “The optimal RI [Rothman Index] thresholds for increased risk of readmission were last ≤ 71, mean ≤ 67, or maximum ≤ 80. The optimal RI thresholds for increased risk of home discharge were minimum ≥ 53, mean ≥ 69, or maximum ≥ 81.”

Dr. Kleven told OTW, “The most important results of this study were that the Rothman Index was significantly associated with increased odds of readmission and home discharge but was not significantly associated with complications following total knee arthroplasty. Rothman Index thresholds were proposed to help orthopedic surgeons identify patients at risk for readmission. In addition, objective thresholds were set that will aid discharge planning location.”