Oude Voshaar MAH Vonkeman HE Courvoisier D Finckh A Gossec L Leung YY Michaud K Pinheiro G Soriano E Wulfraat N Zink A van de Laar MAFJ 2019 OBJECTIVES Outcomes obtained using different physical function patient reported outcome measures (PROMs) are difficult to compare. To facilitate standardization of physical function outcome measurement and reporting we developed an item response theory (IRT) based standardized physical function score metric for ten commonly used physical function PROMs. METHODS Data of a total of 16,386 respondents from representative cohorts of patients with rheumatic diseases as well as the Dutch general population were used to map the items of ten commonly used physical function PROMs on a continuous latent physical function variable. The resulting IRT based common metric was cross-validated in an independent dataset of 243 patients with gout, osteoarthritis or polymyalgia in which four of the linked PROMs were administered. RESULTS Our analyses supported that all 97 items of the ten included PROMs relate to a single underlying physical function variable and that responses to each item could be described by the generalized partial credit IRT model. In the cross-validation analyses we found congruent mean scores for four different PROMs when the IRT based scoring procedures were used. CONCLUSIONS We showed that the standardized physical function score metric developed in this study can be used to facilitate standardized reporting of physical function outcomes for ten commonly used make physical function PROMs. application/pdf https://sonar.ch/global/documents/229754 eng info:eu-repo/semantics/altIdentifier/doi/10.1007/s11136-018-2007-0 info:eu-repo/semantics/altIdentifier/pmid/30317425 info:eu-repo/semantics/openAccess Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation. - 2019 Common metric Item bank Item response theory Patient reported outcomes Physical function Ethnic Groups Female Humans Male Middle Aged Osteoarthritis Outcome Assessment, Health Care Patient Reported Outcome Measures Quality of Life Research Design Rheumatic Diseases Surveys and Questionnaires Towards standardized patient reported physical function outcome reporting: linking ten commonly used questionnaires to a common metric. http://purl.org/coar/resource_type/c_6501