The Effect of Body Mass Index on the Functional Prognosis of Traumatic Brain Injury Patients

Evaluating the association between obesity and discharge functional status after pediatric injury

BACKGROUND

Children with obesity frequently have functional impairment after critical illness. Although obesity increases morbidity risk after trauma, the association with functional outcomes in children is unknown.

OBJECTIVE

To evaluate the association of weight with functional impairment at hospital discharge in children with serious injuries.

METHODS

This secondary analysis of a multicenter prospective study included children <15 years old with a serious injury. Four weight groups, underweight, healthy weight, overweight, and obesity/severe obesity were defined by body mass index z-scores. The functional status scale (FSS) measured impairment across six functional domains before injury and at hospital discharge. New domain morbidity was defined as a change ≥2 points. The association between weight and functional impairment was determined using logistic regression adjusting for demographics, physiological measures, injury details, presence of a severe head injury, and physical abuse.

RESULTS

Although most patients discharged with good/unchanged functional status, new domain morbidity occurred in 74 patients (17%). New FSS domain morbidity occurred in 13% of underweight, 14% of healthy weight, 15% of overweight, and 26% of obese/severe obese patients. Compared to healthy weight patients, those with obesity had more frequent new domain morbidity (p = 0.01), while the other weight groups had similar morbidity. However, after adjustment for confounders, weight was not associated with new functional morbidity at discharge.

CONCLUSION

Patients with obesity have greater frequency of new domain morbidity after a serious injury; however, after accounting for injury characteristics, weight group is not independently associated with new functional morbidity at hospital discharge after injury in children.

LEVEL OF EVIDENCE

III.

The Effect of Body Mass Index on Functional Outcome of Patients With Knee Replacement

Objective

To investigate the effects of body mass index (BMI) on the rehabilitation process in patients with a recent knee replacement.

Design

This retrospective cohort study included all patients admitted to a rehabilitation hospital, with a recent diagnosis of knee replacement and available hospital admission data including height and weight, between 2014 and 2017.

Setting

Rehabilitation hospital.

Participants

Study participants included patients who had undergone knee replacement surgery (N=742), with available BMI data.

Interventions

None.

Main Outcome Measures

FIM scores, including FIM change per day (FIM efficiency) by BMI category.

Results

The chart review identified 742 patients who had undergone knee replacement surgery, with available BMI data. The identified patients ranged in age from 58 to 85 years, with a mean age of 70 years. Of the patients included in the study, 24 were male, 49 were female, 73 were within the normal weight class, 180 in the overweight class, 189 in the obese class I, 143 in the obese class II, and 157 patients were classified as obese class III. The mean FIM efficiency was highest in the obese class II category (3.96). In a multivariate analysis after controlling for age, obese classes II and III had significantly better FIM efficiency.

Conclusion

This study did not demonstrate that obesity adversely affects the rate of recovery during hospitalization after knee replacement surgery.