Alessandro Chiarotto1, Leo D Roorda2, Martine H Crins2, Maarten Boers3, Raymond W Ostelo4, Caroline B Terwee5. 1. Department of Health Sciences, Faculty of Science, Amsterdam Movement Sciences Research Institute, VU University, Amsterdam, The Netherlands; Department of General Practice, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. Electronic address: a.chiarotto@vu.nl. 2. Amsterdam Rehabilitation Research Center, Reade, Amsterdam, The Netherlands. 3. Amsterdam Rheumatology and Immunology Center, VU University Medical Center, Amsterdam, The Netherlands; Department of Epidemiology and Biostatistics, Amsterdam Public Health Research Institute, Amsterdam UMC, VU University Medical Center, Amsterdam, The Netherlands. 4. Department of Health Sciences, Faculty of Science, Amsterdam Movement Sciences Research Institute, VU University, Amsterdam, The Netherlands; Department of General Practice, Erasmus MC, University Medical Center, Rotterdam, The Netherlands. 5. Department of Health Sciences, Faculty of Science, Amsterdam Movement Sciences Research Institute, VU University, Amsterdam, The Netherlands.
Abstract
OBJECTIVE: To compare dimensionality, item-level characteristics, scale-level reliability, and construct validity of PROMIS Physical Function short forms (PROMIS-PF) and 24-item Roland Morris Disability Questionnaire (RMDQ-24) in patients with chronic low back pain (LBP). DESIGN: Cross-sectional study. SETTING: Secondary care center for rehabilitation and rheumatology. PARTICIPANTS: Patients with nonspecific LBP ≥3 months (N=768). Mean age was 49±13 years, 77% were female, and 54% displayed pain for more than 5 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Dutch versions of the 4-, 6-, 8-, 10-, and 20-item PROMIS-PF and of the RMDQ-24. RESULTS: PROMIS-PF-6, PROMIS-PF-8, and RMDQ-24 exhibited sufficient unidimensionality (confirmatory factor analysis: comparative fit index>0.950, Tucker-Lewis index>0.950, root means square error of approximation<0.060), whereas the other instruments did not. All instruments were free of local dependence except PROMIS-PF-20 with 4 item pairs with clear residual correlations. Mokken scale analysis found 1 nonmonotone item for PROMIS-PF-20 and 8 for RMDQ-24 (ie, the probability of endorsing these items was not increasing with increasing level on the underlying construct). PROMIS-PF-20 displayed 2 misfitting items (S-χ2P value>.001). Two-parameter item response theory models found 2 items with low discrimination for RMDQ-24. All other instruments had adequate fit statistics and item parameters. PROMIS-PF-20 displayed the best scale-level reliability. Construct validity was sufficient for all instruments as all hypotheses on expected correlations with other instruments and differences between relevant subgroups were met. CONCLUSIONS: PROMIS-PF-6, PROMIS-PF-8, and RMDQ-24 exhibited better unidimensionality, whereas PROMIS-PF-4, PROMIS-PF-6, PROMIS-PF-8, and PROMIS-PF-10 showed superior item-level characteristics. PROMIS-PF-20 was the instrument with the best scale-level reliability. This study warrants assessment of other measurement properties of PROMIS-PF short forms in comparison with disease-specific physical functioning instruments in LBP.
OBJECTIVE: To compare dimensionality, item-level characteristics, scale-level reliability, and construct validity of PROMIS Physical Function short forms (PROMIS-PF) and 24-item Roland Morris Disability Questionnaire (RMDQ-24) in patients with chronic low back pain (LBP). DESIGN: Cross-sectional study. SETTING: Secondary care center for rehabilitation and rheumatology. PARTICIPANTS: Patients with nonspecific LBP ≥3 months (N=768). Mean age was 49±13 years, 77% were female, and 54% displayed pain for more than 5 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Dutch versions of the 4-, 6-, 8-, 10-, and 20-item PROMIS-PF and of the RMDQ-24. RESULTS: PROMIS-PF-6, PROMIS-PF-8, and RMDQ-24 exhibited sufficient unidimensionality (confirmatory factor analysis: comparative fit index>0.950, Tucker-Lewis index>0.950, root means square error of approximation<0.060), whereas the other instruments did not. All instruments were free of local dependence except PROMIS-PF-20 with 4 item pairs with clear residual correlations. Mokken scale analysis found 1 nonmonotone item for PROMIS-PF-20 and 8 for RMDQ-24 (ie, the probability of endorsing these items was not increasing with increasing level on the underlying construct). PROMIS-PF-20 displayed 2 misfitting items (S-χ2P value>.001). Two-parameter item response theory models found 2 items with low discrimination for RMDQ-24. All other instruments had adequate fit statistics and item parameters. PROMIS-PF-20 displayed the best scale-level reliability. Construct validity was sufficient for all instruments as all hypotheses on expected correlations with other instruments and differences between relevant subgroups were met. CONCLUSIONS: PROMIS-PF-6, PROMIS-PF-8, and RMDQ-24 exhibited better unidimensionality, whereas PROMIS-PF-4, PROMIS-PF-6, PROMIS-PF-8, and PROMIS-PF-10 showed superior item-level characteristics. PROMIS-PF-20 was the instrument with the best scale-level reliability. This study warrants assessment of other measurement properties of PROMIS-PF short forms in comparison with disease-specific physical functioning instruments in LBP.
Authors: Herman Taylor; Gari Clifford; Tony Nguyen; Corey Shaw; Brittney Newton; Sherilyn Francis; Mohsen Salari; Chad Evans; Camara Jones; Tabia Henry Akintobi Journal: JMIR Form Res Date: 2022-01-11
Authors: Inger L Abma; Bas J D Butje; Peter M Ten Klooster; Philip J van der Wees Journal: Health Qual Life Outcomes Date: 2021-02-24 Impact factor: 3.186