SF-6D Values Stratified by Specific Diagnostic Indication

Study Design. Longitudinal cohort. Objective. To present Oswestry Disability Index scores and SF-6D utility values among patients with different diagnostic etiologies who underwent fusion surgery. Summary of Background Data. Several studies have increased our understanding of health-related quality-of-life measures in patients with low back pain. With rising health care costs, cost-utility analysis is increasingly used by decision makers. Thus, clinicians and researchers need to understand the psychometrics and clinical importance of health state utility values in patients with spine disorders. Methods. A total of 1104 patients who had decompression and lumbar fusion with complete data to compute the SF-6D score at baseline and 2-year follow-up were identified. Primary surgical cases were classified as disc pathology (n = 200), spondylolisthesis (n = 288), instability (n = 43), stenosis (n = 134), or scoliosis (n = 44). Revision cases were classified as nonunion (n = 94), adjacent-level degeneration (n = 98), or postdiscectomy revision (n = 203). Baseline SF-6D and change in SF-6D scores at 2 years were compared among the groups as well as primary versus revision cases. Results. There were 674 women and 430 men. The mean age at surgery was 56.65 +/- 12.7 years. There were 220 (19.9%) smokers. The worst mean baseline SF-6D score was in patients with nonunion (0.492), followed by disc pathology (0.493), adjacentlevel degeneration (0.494), postdiscectomy revision (0.499), stenosis (0.504), instability (0.512), spondylolisthesis (0.520), and scoliosis (0.530). There was a statistically significant difference in baseline SF-6D score among the different groups (P = 0.002). The mean change in SF-6D score was greatest in patients with stenosis (0.088), followed by spondylolisthesis (0.085), scoliosis (0.076), disc pathology (0.076), instability (0.073), postdiscectomy revision (0.070), adjacent-level degeneration (0.066), and nonunion (0.050). There was no statistically significant difference in change in SF-6D score among the different groups (P = 0.096). However, revision cases had statistically significantly smaller gains in SF-6D score (0.064) than primary cases (0.082, P = 0.012). Conclusion. Patients with lumbar degenerative disorders have health state values similar to patients with chronic renal disease, Crohn's disease, or coronary artery disease. Health state values of patients with different indications for surgery differ at baseline and after surgery. Revision cases have worse baseline SF-6D scores and less improvement in scores at 2 years after surgery than primary cases. Further studies are needed to gain a greater understanding of health state utility values in patients with lumbar degenerative disorders.