Premium
Linking Physical Function Outcomes in Rheumatology: Performance of a Crosswalk for Converting Health Assessment Questionnaire Scores to Short Form 36 Physical Functioning Scale Scores
Author(s) -
Oude Voshaar Martijn A. H.,
ten Klooster Peter M.,
Taal Erik,
Wolfe Frederick,
Vonkeman Harald,
Glas Cees A. W.,
de Laar Mart A. F. J.
Publication year - 2014
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.22357
Subject(s) - medicine , schema crosswalk , intraclass correlation , physical therapy , rheumatoid arthritis , rheumatology , fibromyalgia , reliability (semiconductor) , psychometrics , clinical psychology , power (physics) , physics , pedestrian , quantum mechanics , transport engineering , engineering
Objective To evaluate the reliability of a crosswalk, developed in The Netherlands, between the Health Assessment Questionnaire (HAQ) disability index (DI) and the Short Form 36 physical functioning scale (PF‐10) in a sample of patients with various rheumatic diseases in the US. Methods Baseline data from patients with rheumatoid arthritis (RA; n = 29,020), fibromyalgia (FM; n = 3,776), and systemic lupus erythematosus (SLE; n = 1,609) participating in the National Data Bank for Rheumatic Diseases were analyzed. Reliability of the crosswalk was evaluated by calculating intraclass correlation coefficients (ICCs), and agreement between observed and predicted scores was evaluated using the Bland‐Altman approach. Results The crosswalk produced reliable conversions for both the HAQ DI (ICC range 0.70–0.77) and PF‐10 (ICC range 0.73–0.78) in all 3 disease groups. The mean difference between observed and expected scores was close to zero in US patients with RA. For all 3 disease groups, the limits of agreement were fairly wide and conversion at the level of individual patients is not recommended. Conclusion The crosswalk produced reliable conversions at the group level in a crosscultural setting and can be used to convert HAQ DI to PF‐10 scores and vice versa in US patients with RA, FM, or SLE.