title: Obesity is associated with inferior results after surgery for lumbar spinal stenosis: a study of 2633 patients from the Swedish spine register.
abstract: METHODS
  A cohort study based on the Swedish Spine Register.
  
  
  OBJECTIVE
  To determine the association between body mass index (BMI) and outcome of lumbar spine surgery for spinal stenosis.
  
  
  BACKGROUND
  Several small studies have sought to evaluate the importance of obesity in relation to results after surgery for lumbar spinal stenosis (LSS), but the findings are inconsistent and relatively weak.
  
  
  METHODS
  All patients who underwent surgery for LSS from January 1, 2006, to June 30, 2008, with a completed 2-year follow-up in the Swedish Spine Register were included. Logistic regression was used to assess the association between BMI and different outcomes.
  
  
  RESULTS
  Of the 2633 patients enrolled, 819 (31%) had normal weight, 1208 (46%) were overweight, and 606 (23%) were obese. On average, all 3 BMI groups achieved significant improvements after surgery. A higher BMI, however, was associated with greater odds of dissatisfaction after surgery and inferior results at the 2-year follow-up. After adjusting for differences in baseline characteristics, the obese group demonstrated inferior function and quality of life as measured by the Oswestry Disability Index (ODI) and the EuroQol Group Index (EQ-5D), respectively. At the 2-year follow-up, obese patients had a mean ODI of 33 (95% confidence interval [CI], 31-34) and mean EQ-5D of 0.56 (95% CI, 0.54-0.59) compared with a mean ODI of 25 (95% CI, 24-26) and mean EQ-5D of 0.64 (95% CI, 0.62-0.66) in the normal weight group. When compared with the normal weight patients, the adjusted odds ratio for dissatisfaction was 1.73 in the obese group (95% CI, 1.36-2.19). Differences between the normal weight and overweight groups were modest and therefore could not be considered clinically relevant.
  
  
  CONCLUSIONS
  Obese patients achieved significant pain reduction, better walking ability, and improved quality of life after surgical treatment of LSS. Nevertheless, obesity was associated with a higher degree of dissatisfaction and poorer outcomes after surgery for LSS.
authors.affiliation: Department of Surgical Sciences, Uppsala University, Department of Orthopaedics, Sundsvall Hospital, Sweden. bjorn.knutsson@lvn.se
authors.forename: Björn
authors.initials: B
authors.lastname: Knutsson
authors.forename: Karl
authors.initials: K
authors.lastname: Michaëlsson
authors.forename: Bengt
authors.initials: B
authors.lastname: Sandén
mesh_terms: D000368:Aged; D000700:Analgesics / Q000627:therapeutic use; D015992:Body Mass Index; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology; D016017:Odds Ratio; D019637:Orthopedic Procedures / Q000009:adverse effects*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control; D017060:Patient Satisfaction; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D011788:Quality of Life; D020127:Recovery of Function; D012042:Registries; D012307:Risk Factors; D013130:Spinal Stenosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D011795:Surveys and Questionnaires; D013548:Sweden; D013997:Time Factors; D016896:Treatment Outcome; D016138:Walking
chemical_list: D000700:Analgesics