Preference-based quality of life measurement in patients with cervical spondylotic myelopathy.
METHODS
Prospective cross-sectional observational cohort study.


OBJECTIVE
To assess the performance of preference-based quality of life (QOL) instruments in patients with cervical spondylotic myelopathy (CSM).


BACKGROUND
Generic health status instruments (e.g., SF-36) or disease-specific health status measures (e.g., myelopathy scales) are typically used to measure QOL in patients with CSM; however, these instruments only examine a limited number of domains that contribute to QOL. An alternative is preference-based QOL methods, which integrate all factors contributing to QOL and provide a comprehensive individualized measure of how patients value their current health state.


METHODS
We used four preference-based QOL methods to measure QOL in a cohort of 79 patients with CSM: 1) visual analogue scale, 2) standard gamble, 3) time trade-off, and 4) willingness to pay. We measured health status with the SF-36 and with CSM disease-specific scales devised by Nurick, Harsh, Cooper, and the Japanese Orthopedic Association. We used multivariate linear regression techniques to examine the relationships between preference-based QOL, generic health status, CSM disease-specific health status, and patient characteristics.


RESULTS
Median preference-based QOL measurements for the CSM cohort were as follows: visual analogue scale, 0.50; standard gamble, 0.79; time trade-off, 0.75, and willingness to pay, $38,256. Preference-based QOL was not well explained by generic health status, CSM disease-specific health status, or patient characteristics, as shown by regression models that were unable to account more than 21% of the variation in preference-based QOL (R < or =0.21).


CONCLUSIONS
Preference-based QOL in patients with CSM is poorly correlated with generic health status, CSM disease-specific health status, or patient characteristics. Studies of CSM and other spine diseases should consider incorporating preference-based QOL measures for a fuller evaluation of the impact of spine disease and its treatment on QOL.
King
Joseph T
JT
Section of Neurosurgery, Surgical Service Line, Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA. Joseph.KingJr@med.va.gov
Tsevat
Joel
J
Moossy
John J
JJ
Roberts
Mark S
MS
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae; D003430:Cross-Sectional Studies; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011446:Prospective Studies; D011788:Quality of Life; D013128:Spinal Osteophytosis / Q000175:diagnosis*