Purpose: Patient-reported outcome (PRO) measures originally developed for paper administration are increasingly being administered electronically in clinical trials and other health research studies. Three published meta-analyses of measurement equivalence among paper and electronic modes aggregated findings across hundreds of PROs, but there has not been a similar meta-analysis that addresses a single PRO, partly because there are not enough published measurement equivalence studies using the same PRO. Because the SF-36(R) Health Survey (SF-36) is a widely used PRO, the aim of this study was to conduct a meta-analysis of measurement equivalence studies of this survey.
Methods: A literature search of several medical databases used search terms for variations of "SF-36" or "SF-12" and "equivalence" in the title or abstract of English language publications. The eight scale scores and two summary measures of the SF-36 and SF-12 were transformed to norm-based scores (NBS) using developer guidelines. A threshold of within ± 2 NBS points was set as the margin of equivalence. Comprehensive meta-analysis software was used.
Results: Twenty-five studies were included in the meta-analysis. Results indicated that mean differences across domains and summary scores ranged from 0.01 to 0.39 while estimates of agreement ranged from 0.76 to 0.91, all well within the equivalence threshold. Moderator analyses showed that time between administration, survey language, and type of electronic device did not influence equivalence.
Conclusions: The results of the meta-analysis support equivalence of paper-based and electronic versions of the SF-36 and SF-12 across a variety of disease populations, countries, and electronic modes.
Keywords: Electronic; Equivalence; Measurement; Meta-analysis; PRO; Patient-reported outcomes; SF-36; ePRO.