Influence of Body Mass Index on Subjective and Objective Measures of Pain, Functional Impairment, and Health-Related Quality of Life in Lumbar Degenerative Disc Disease.
OBJECTIVE
To analyze the influence of body mass index (BMI) on subjective and objective measures of pain, functional impairment, and health-related quality of life in patients with lumbar degenerative disc disease undergoing surgery.


METHODS
Prospective institutional review board-approved 2-center study, measuring visual analog scale (VAS) back and leg pain, Roland-Morris Disability Index (RMDI), Oswestry Disability Index (ODI), EuroQol 5D questionnaire, and Short Form-12 at baseline, 6 weeks, 6 months, and 1 year postoperatively. T-scores of objective functional impairment (OFI) were determined using the Timed Up and Go (TUG) test.


RESULTS
A total of 375 patients with a median BMI of 26.6 kg/m2(94 obese patients [BMI ≥30 kg/m2]) were included. Obese patients presented more VAS back pain (mean, 4.7 vs. 3.6; P = 0.001) and greater disability on the RMDI (mean, 12.6 vs. 11.3; P = 0.045). The prevalence and severity of OFI were similar in obese and nonobese patients. There was a weak positive correlation between BMI and VAS back pain (r = 0.1552; P = 0.0026), on both RMDI (r = 0.1138; P = 0.0276) and ODI (r = 0.1075; P = 0.0374). There was no correlation between BMI and TUG T-scores (r = 0.0475; P = 0.3585). Obese patients were as likely as nonobese patients to show a positive 6-week treatment response, and the outcome up to 1 year was similar.


CONCLUSIONS
BMI positively correlates with VAS back pain, RMDI, and ODI. Standardized TUG T scores reflect the patient's degree of OFI well, irrespective of BMI. The TUG test appears to be a good means to estimate functional impairment in populations with a high prevalence of obesity.
Department of Neurosurgery, Faculty of Medicine, University Hospital Geneva, Geneva, Switzerland. Electronic address: mnstienen@gmail.com.
Martin N
MN
Stienen
Department of Neurosurgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
Holger
H
Joswig
School of Medicine and Public Health, University of Newcastle, Newcastle, Australia.
Nicolas R
NR
Smoll
Department of Neurosurgery, Faculty of Medicine, University Hospital Geneva, Geneva, Switzerland.
Marco V
MV
Corniola
Department of Neurosurgery, Faculty of Medicine, University Hospital Geneva, Geneva, Switzerland.
Karl
K
Schaller
Department of Neurosurgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
Gerhard
G
Hildebrandt
Department of Neurosurgery, Faculty of Medicine, University Hospital Geneva, Geneva, Switzerland.
Oliver P
OP
Gautschi
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications* / Q000453:epidemiology / Q000523:psychology*; D007405:Intervertebral Disc Displacement / Q000150:complications* / Q000453:epidemiology / Q000523:psychology*; D016014:Linear Models; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology*; D010147:Pain Measurement; D011788:Quality of Life / Q000523:psychology*; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D013557:Switzerland
Body mass index; Body weight; Degenerative disc disease; Disability; Health-related quality of life; Impairment; Obesity; Objective functional impairment; Pain; Patient evaluation; Timed Up and Go test