To evaluate the responsiveness of the SF-36 Health Survey in drug trials and to determine how often clinically efficacious treatments produce meaningful functional health changes across medical conditions.
We conducted a systematic review of randomized, double-blind, placebo-controlled drug trials published from 1995 to 2011 that documented results for primary clinical endpoints and SF-36 outcomes. PubMed and a database of SF-36 publications were searched. We evaluated responsiveness as concordance (both statistically significant or both nonsignificant) between primary clinical and SF-36 outcomes. To determine how often SF-36 physical and mental component summary (PCS, MCS) score changes were of meaningful magnitude, mean net of placebo changes with treatment were compared against the developer’s recommended 3-point threshold for a minimal important difference (MID) across groups of medical conditions.
Of 805 screened trials, 185 met eligibility criteria. Primary clinical and SF-36 outcomes were concordant in 151 trials (82%). Among clinically efficacious trials, 58% reported net mean SF-36 improvements ≥MID threshold; however, SF-36 changes were often modest (PCS IQR, 1.6–4.1; MCS IQR, 0.8–3.5). Variations in treatment impact were apparent across conditions. Clinically efficacious therapies for rheumatoid arthritis, psoriatic arthritis, and psoriasis consistently achieved the largest SF-36 improvements, with 87% exceeding MID, whereas no efficacious therapies for peripheral arterial disease or chronic obstructive pulmonary disease achieved MID threshold.
The SF-36 responds to treatment impact, distinguishing drug therapies that, on average, produce meaningful functional health benefits. Overall, just over half of clinically efficacious trials report meaningful functional health improvements, and results vary widely by medical condition.
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*Department of Quantitative Health Sciences, University of Massachusetts Medical School
†John Ware Research Group, Worcester, MA
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Presented at international conferences as posters at ISPOR 2013, New Orleans, LA and ICPE 2013, Montreal, Canada.
J.E.W.: consultancy and expert testimony for industry sponsors, payment for lectures at the Harvard School of Public Health, and stock interest in John Ware Research Group Inc. Although J.E.W. has no financial conflicts to declare related to the SF-36, some readers may perceive J.E.W.’s prior work as the original developer of the SF-36 and its second version as a potential conflict. D.M.F. declares no conflict of interest.
Reprints: Daniel M. Frendl, MS, Department of Quantitative Health Sciences, University of Massachusetts Medical School, Albert Sherman Center 6th Floor, 368 Plantation St, Worcester, MA 01605. E-mail: firstname.lastname@example.org.