title: Surgery for degenerative cervical myelopathy: a patient-centered quality of life and health economic evaluation.
abstract: Degenerative cervical myelopathy (DCM) represents the most common cause of non-traumatic spinal cord impairment in adults. Surgery has been shown to improve neurologic symptoms and functional status, but it is costly. As sustainability concerns in the field of health care rise, the value of care has come to the forefront of policy decision-making. Evidence for both health-related quality of life outcomes and financial expenditures is needed to inform resource allocation decisions.
  
  
  
  This study aimed to estimate the lifetime incremental cost-utility of surgical treatment for DCM.
  
  
  
  This is a prospective observational cohort study at a Canadian tertiary care facility.
  
  
  
  We recruited all patients undergoing surgery for DCM at a single center between 2005 and 2011 who were enrolled in either the AOSpine Cervical Spondylotic Myelopathy (CSM)-North America study or the AOSpine CSM-International study.
  
  
  
  Health utility was measured at baseline and at 6, 12, and 24 months following surgery using the Short Form-6D (SF-6D) health utility score. Resource expenditures were calculated on an individual level, from the hospital payer perspective over the 24-month follow-up period. All costs were obtained from a micro-cost database maintained by the institutional finance department and reported in Canadian dollars, inflated to January 2015 values.
  
  
  
  Quality-adjusted life year (QALY) gains for the study period were determined using an area under the curve calculation with a linear interpolation estimate. Lifetime incremental cost-to-utility ratios (ICUR) for surgery were estimated using a Markov state transition model. Structural uncertainty arising from lifetime extrapolation and the single-arm cohort design of the study were accounted for by constructing two models. The first included a highly conservative assumption that individuals undergoing nonoperative management would not experience any lifetime neurologic decline. This constraint was relaxed in the second model to permit more general parameters based on the established natural history. Deterministic and probabilistic sensitivity analyses were employed to account for parameter uncertainty. All QALY gains and costs were discounted at a base of 3% per annum. Statistical significance was set at the .05 level.
  
  
  
  The analysis included 171 patients; follow-up was 96.5%. Mean age was 58.2±12.0 years and baseline health utility was 0.56±0.14. Mean QALY gained over the 24-month study period was 0.139 (95% confidence interval: 0.109-0.170, p<.001) and the mean 2-year cost of treatment was $19,217.82±12,404.23. Cost associated with the operation comprised 65.7% of the total. The remainder was apportioned over presurgical preparation and postsurgical recovery. Three patients required a reoperation over the 2-year follow-up period. The costs of revision surgery represented 1.85% of the total costs. Using the conservative model structure, the estimated lifetime ICUR of surgical intervention was $20,547.84/QALY gained, with 94.7% of estimates falling within the World Health Organization definition of "very cost-effective" ($54,000 CAD). Using the more general model structure, the estimated lifetime ICUR of surgical intervention was $11,496.02/QALY gained, with 97.9% of estimates meeting the criteria to be considered "very cost-effective."
  
  
  
  Surgery for DCM is associated with a significant quality of life improvement. The intervention is cost-effective and, from the perspective of the hospital payer, should be supported.
authors: Toronto Western Hospital, 399 Bathurst St, WW 4-437, Toronto, Ontario M5T 2S8, Canada; Department of Public Health Sciences, The University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637, USA.
authors: Christopher D
authors: CD
authors: Witiw
authors: Faculty of Medicine, University of Toronto Medical Sciences, Building 1 King's College Circle, Room 2374 Toronto, Ontario M5S 1A8, Canada.
authors: Lindsay A
authors: LA
authors: Tetreault
authors: Department of Public Health Sciences, The University of Chicago, 5841 S Maryland Ave, Chicago, IL 60637, USA.
authors: Fabrice
authors: F
authors: Smieliauskas
authors: Department of Health Services, University of Washington, 1959 NE Pacific St, Magnuson Health Sciences Center, Room H-680, Box 357660, Seattle, WA 98195-7660.
authors: Branko
authors: B
authors: Kopjar
authors: Toronto Western Hospital, 399 Bathurst St, WW 4-437, Toronto, Ontario M5T 2S8, Canada.
authors: Eric M
authors: EM
authors: Massicotte
authors: Toronto Western Hospital, 399 Bathurst St, WW 4-437, Toronto, Ontario M5T 2S8, Canada; McEwen Centre for Regenerative Medicine, Toronto Western Hospital, University Health Network, 399 Bathurst St, Toronto, Ontario M5T 2S8, Canada; Department of Surgery, University of Toronto, Stewart Building, 149 College St, 5th Floor, Toronto, Ontario M5T 1P5, Canada. Electronic address: Michael.Fehlings@uhn.ca.
authors: Michael G
authors: MG
authors: Fehlings
mesh_terms: D002170:Canada; D002574:Cervical Vertebrae / Q000601:surgery*; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000191:economics*; D018802:Patient-Centered Care / Q000191:economics*; D011446:Prospective Studies; D011788:Quality of Life; D012086:Reoperation / Q000191:economics; D013118:Spinal Cord Diseases / Q000191:economics / Q000601:surgery
keywords: Cost-utility; Degenerative cervical myelopathy; Health economics; Quality of life; Surgery; Value