Session number: 1129
Abstract title: Quality of Life Assessment with the SF-36 in VA Cervical Spondylotic Myelopathy Patients
Author(s):
JT King Jr - Center for Health Equity Research and Promotion, VA Pittsburgh Healthcare System
MS Roberts - Division of General Internal Medicine, University of Pittsburgh
Objectives: Cervical spondylotic myelopathy (CSM) is a chronic degenerative condition of the cervical spine producing narrowing of the spinal canal and disruption of spinal cord function. We assessed quality of life measurement in a cohort of CSM patients using disease specific measures and a generic measure, the Medical Outcomes Study Short Form-36 (SF-36).
Methods: A cohort of 74 VA neurosurgery clinic CSM patients underwent structured interviews to collect data on demographics, symptoms, and comorbid diseases. Patients also completed the SF-36. Symptoms and exam findings were used to assign a score to each patient on the myelopathy scales of Nurick, Cooper, Harsh, and a modification of the Japanese Orthopaedic Association (mJOA) scale. SF-36 scores were compared to age-matched VA and US population norms using t-tests with unequal variances. Cuzick’s nonparametric test for trend was used to explore the relationship between the SF-36 physical component summary score (PCS) and the myelopathy scales. SF-36 construct validity was assessed by determining whether SF-36 scores varied in accordance with predefined hypotheses relating to the myelopathy scores, using Cuzick’s non-parametric test for trend. The reliability of the SF-36 scores was assessed with Cronbach’s alpha.
Results: CSM patients had decreased quality of life across all eight SF-36 domains and the PCS and MCS scores when compared to age-matched VA and US population norms (for all, P<0.013). Lower PCS scores were associated with worse myelopathy scores on the scales of Nurick (P<0.01), Cooper leg subscale (P=0.06), and Harsh (P<0.01). SF-36 construct validity was demonstrated by confirming most of our hypothesized relationships between SF-36 scales and the myelopathy scales (P<0.05). Reliability was demonstrated for all eight SF-36 domain scales and the physical component and mental component summary scales, where Cronbach’s alpha satisfied Nunnally’s criterion of 0.7.
Conclusions: CSM adversely affects quality of life across all health domains measured by the SF-36, a generic health outcomes measurement instrument. The effects of CSM extend beyond the motor, sensory, and bladder dysfunction captured by myelopathy scales into emotional and mental realms. The SF-36 is a valid and reliable instrument for use in patients with CSM.
Impact statement: Studies assessing CSM outcomes should include both validated generic outcomes instruments such as the SF-36, and disease-specific measures.