期刊名称：Epidemiology, Biostatistics and Public Health
印刷版ISSN：2282-0930
出版年度：2018
卷号：15
期号：3
DOI：10.2427/12839
语种：English
出版社：PREX
其他摘要：Background: Differential item functioning (DIF) presents when individuals from different groups perceive the meaning of items differently in health-related quality of life (HRQoL) questionnaires. The aim of this study is to distinguish DIF in the SF-36 questionnaire and to determine its effect on comparison of HRQoL scores of lumbar disc herniation (LHD) patients and a healthy population. Methods: A total of 137 patients with LHD and 691 healthy individuals filled out the Persian version of the SF-36 questionnaire. The Rasch model was used to assess DIF for patients with LDH and a healthy population. Results: The presence of DIF was determined in 6 of 8 (75%) domain scores between patients with LDH and healthy individuals. Although half of the DIF was categorized as either negligible (3 out of 8; 37.5%), high DIF was observed in 3 out of 8 domains (37.5%). Gender was not flagged as important to DIF, with only 3 of 8 (37.5%) categorized as negligible. Conclusion: Because the use of the SF-36 questionnaire in HRQoL assessment between groups may not be invariant, caution should be used during comparison of HRQoL scores between heterogeneous groups.
