The practicality and validity of directly elicited and SF-36 derived health state preferences in patients with low back pain

摘要: Recent research has derived preference scores from the SF-36. We compare practicality and construct validity of SF-36 with directly elicited time trade off (TTO) visual analogue scale (VAS) scores. In this observational study, low back pain (LBP), patients were asked to complete disease specific, generic (SF-36), health state (VAS TTO) instruments. Baseline responses converted using six published algorithms. Response rates for TTO values 354 379 (93%) 303 (80%), respectively. Thirty excluded exercise because difficulties comprehending scaling task. Choice based methods (standard gamble, yielded higher more uniform estimates (0.77–0.79) than non-choice (0.42–0.70). Directly variable had less power distinguish among differing severity LBP. All preferences exhibited a minimum threshold implying potential floor effect severely ill patients. demonstrated good in setting, however different will yield disparate marginal benefit. This emphasises need standardised algorithm deriving Copyright © 2001 John Wiley & Sons, Ltd.