Rehabilitation Length of Stay, Body Mass Index, and Functional Improvement among Adults with Traumatic Spinal Cord Injury

Published:November 16, 2021DOI:



      Examine the modifying effect of body mass index (BMI) on the association between rehabilitation length of stay (LOS), severity of injury, and motor FIM® (mFIM) improvement in patients with traumatic spinal cord injury (TSCI).


      Retrospective cohort study.


      Seventeen SCI Model Systems (SCIMS) centers in the United States.


      3,413 patients who has a TSCI admitted to an SCIMS between October 2011 and August 2018.


      Not applicable.

      Main Outcome Measures

      The mFIM (12 items) improvement by discharge. Four rehabilitation LOS groups split by quartiles were created for each neurologic severity of injury group (C1-C4 level with American Spinal Injury Impairment Scale [AIS) ABC, C5-C8 AIS ABC, T1-S3 AIS ABC, and AIS DE). The interrelationship among rehabilitation LOS, BMI, and mFIM improvement were examined using multivariate linear regressions. A stratified analysis was performed to examine the association between rehabilitation LOS and mFIM improvement by BMI status (under or normal weight, overweight, and obese) and neurologic groups.


      1099 (32.2%) and 821 (24.1%) patients were overweight and obese, respectively. Patients with obesity had less improvement in mFIM than those who were under or normal weight (unit of mFIM improvement =-3.71). After stratifying by BMI status, among obese patients, those with the longest rehabilitation LOS showed greater improvement in mFIM than those in the shortest LOS (unit of mFIM improvement =4.78).


      Longer inpatient rehabilitation LOS may benefit patients with TSCI by increasing mFIM improvement by discharge. Obesity is negatively associated with mFIM improvement.

      Key words

      List of abbreviations:

      AIS (American Spinal Injury Association Impairment Scale), CI (confidence interval), LOS (length of stay), mFIM (motor FIM®), TSCI (traumatic spinal cord injury), SCIMS (Spinal Cord Injury Model Systems), VIF (variance inflation factor)
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