A Few Assumptions to Start
• You have an interest in how a patient’s body
composition affects their rehab outcome
• You know that BMI does not stand for
Because Measures are Important
• You have at least one belief about how BMI could
affect inpatient rehab outcomes after stroke
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Body Mass Index: Does it Matter in Rehab?
Literature reports that HIGHER BMI is associated with:
↓ FIM® function scores
↑ LOS
↑ Hospital costs
↓ Mortality rates
↓ Stroke recurrence
↑ Improvements in functional outcomes
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Effect of BMI on Select Inpatient Rehabilitation
Outcomes after Stroke
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Measures of patient function
used in this analysis are based
on data collected using the FIM®
instrument, property of Uniform
Data System for Medical
Rehabilitation, a division of UB
Foundation Activities, Inc.
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Body Mass Index: Does it Matter in Rehab?
How We Looked for an Answer
• Data Source: CIHI National Rehabilitation Reporting
System (NRS)
– Adult inpatient rehabilitation programs
– ~100 participating facilities in 9 provinces
– Comprehensive reporting in Ontario since 2002
– Height and weight mandatory since 2010
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Body Mass Index: Does it Matter in Rehab?
How We Looked for an Answer
• Three full years of inpatient stroke rehab (2010-2013)
– 14,197 episodes of inpatient stroke rehab
• Regression models: effect of BMI group on rehab LOS
and returning home after rehab
– Models adjusted for variables expected to influence
outcomes
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Body Mass Index: Does it Matter in Rehab?
What We See
Model-Adjusted LOS (mean, days)
* Different
from
NORMAL
p< 0.05
*
40.9
Underweight
(n = 601)
40.2
40.1
40.3
40.7
Normal
(n = 5,385)
Overweight
(n = 5,007)
Moderately
Obese
(n = 2,839)
Severely Obese
(n = 365)
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Body Mass Index: Does it Matter in Rehab?
What We See
Model-Adjusted % of Patients Returning Home
100%
75%
78%
80%
79%
68%
*
0%
*
50%
Underweight Normal Overweight Moderately Severely
Obese
(n=549)
Obese
(n=5,027) (n=4,726)
(n=2,708) (n=350)
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* Different from NORMAL p< 0.05
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Body Mass Index: Does it Matter in Rehab?
How We Can Interpret our Answer
• Comparable increases in function regardless of
admission BMI group
• Underweight patients:
– Stayed longer to achieve comparable increases in function
– Less likely to be discharged back home
• Interventions in underweight individuals are needed to
optimize inpatient rehabilitation care delivery
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Additional Variables Included in the Regression
Models
• Age
• Total FIM® Function Score at Admission
• Number of Pre-Admission Comorbidities
• Sex
• Type of Stroke
• Onset Time
• Discharge Destination (for LOS only)
• Comorbidity of Depression
• Comorbidity of Hypothyroidism
• Comorbidity of Congestive Heart Failure
• Comorbidity of Hypertension
• Comorbidity of Diabetes
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