RT - Journal Article T1 - Response shift in quality of life assessment among cancer patients: A study from Iran JF - MJIRI YR - 2017 JO - MJIRI VO - 31 IS - 1 UR - http://mjiri.iums.ac.ir/article-1-3464-en.html SP - 798 EP - 803 K1 - Quality of life K1 - Response shift K1 - Conventional change K1 - Adjusted change K1 - Then test AB - Background: During the course of disease, particularly of chronic diseases, changes in internal standards cause certain changes in the estimation of quality of life (QOL). These changes indicate the phenomenon of ‘response shift’. The present study aimed at assessing response shift in different scales of QOL in Iranian cancer patients. Methods: To assess response shift through the ‘then test’ approach, we asked 211 cancer patients to complete the EORTC QLQ-C30 questionnaire at pretest (at the beginning of the study), posttest (3 months later), and then test (administered immediately after the posttest). Paired t test and Cohen’s effect size were used for comparison. Results: Response shift was significant in all 4 scales under study, i.e. fatigue, pain, emotional functioning, and general QOL (p<0.001). Fatigue, pain, and global QOL have deteriorated significantly with then test approach and emotional function was significantly improved. Conclusion: We observed a response shift in Iranian cancer patients in our study. Thus, in light of the multifactorial nature of QOL and the effect of the response shift bias on different aspects of QOL changes, it is of utmost importance to keep this bias in mind when interpreting the results and managing cancer patients’ treatment regimens. LA eng UL http://mjiri.iums.ac.ir/article-1-3464-en.html M3 10.14196/mjiri.31.120 ER -