title: Quality of Life and General Health After Elective Surgery for Cervical Spine Pathologies: Determining a Valid and Responsive Metric of Health State Utility.
abstract: BACKGROUND
  As part of the Affordable Care Act, health utility metrics are being investigated to define a cost-effective, value-based health care model. EuroQOL-5D (EQ-5D) and Short Form-6D (SF-6D) are commonly used quality-of-life instruments. Domains in the EQ-5D questionnaire are thought to be less responsive in measuring quality of life after cervical surgery.
  
  
  OBJECTIVE
  To evaluate the validity and responsiveness of SF-6D and EQ-5D in determining health and quality of life after elective cervical spine surgery.
  
  
  METHODS
  A total of 420 patients undergoing elective cervical spine surgery over a period of 2 years were enrolled in a prospective longitudinal registry. Patient-reported outcomes Neck Disability Index (NDI), EQ-5D, and SF-12 were recorded. Based on previously published equations, SF-6D was calculated using NDI and SF-12 scores. Patients were asked whether "surgery met their expectations" (meaningful improvement). The validity and relative responsiveness of SF-6D (NDI), SF-6D (SF-12), and EQ-5D to discriminate between meaningful and nonmeaningful improvement were calculated.
  
  
  RESULTS
  Sixty-six percent of patients (277) reported a level of improvement after surgery that met their expectations (meaningful improvement). SF-6D (NDI) (area under the curve [AUC] = 0.69) was a more valid discriminator of meaningful improvement compared with the SF-6D (SF-12) (AUC = 0.65) and EQ-5D (AUC = 0.62). SF-6D (NDI) was also a more responsive measure compared with SF-6D (SF-12) and EQ-5D (standardized response mean difference: 0.66, 0.48, and 0.44, respectively).
  
  
  CONCLUSIONS
  SF-6D is a more valid and responsive measure of general health and quality of life compared with EQ-5D. SF-6D derived from disease-specific disability scores was more valid and responsive than that derived from the generic preference-based SF-12. Cost-effective studies should use SF-6D as a measure of QALY after cervical spine surgery.
authors.affiliation: *Department of Orthopedics Surgery and Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee; ‡Department of Neurological Surgery, Carolina Neurosurgery and Spine Associates, Charlotte, North Carolina.
authors.forename: Silky
authors.initials: S
authors.lastname: Chotai
authors.forename: Scott L
authors.initials: SL
authors.lastname: Parker
authors.forename: Ahilan
authors.initials: A
authors.lastname: Sivaganesan
authors.forename: Saniya S
authors.initials: SS
authors.lastname: Godil
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McGirt
authors.forename: Clinton J
authors.initials: CJ
authors.lastname: Devin
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000473:pathology* / Q000601:surgery*; D017558:Elective Surgical Procedures / Q000523:psychology / Q000592:standards* / Q000639:trends; D005260:Female; D006304:Health Status; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D058991:Patient Protection and Affordable Care Act / Q000592:standards; D011446:Prospective Studies; D011788:Quality of Life / Q000523:psychology; D012042:Registries; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D014481:United States