The Role of Response-Shift in Studies Assessing Quality of Life Outcomes Among Cancer Patients: A Systematic Review

Abstract

Objective: Response-shift has been cited as an important measurement consideration when assessing patient reported quality of life (QoL) outcomes over time among patients with severe chronic conditions. Here we report the results of a systematic review of response shift in studies assessing QoL among cancer patients. Methods: A systematic review using MEDLINE, EMBASE, and PsychINFO along with a manual search of the cited references of the articles selected, was conducted. A quality review was performed using STROBE criteria and reported according to PRISMA guidelines. Results: A systematic review of 1,487 records published between 1,887 and December 2018 revealed 104 potentially eligible studies, and 35 studies met inclusion criteria for content and quality. The most common cancer patient populations investigated in these studies were breast (18 studies), lung (14 studies), prostate (eight studies), and colorectal (eight studies). Response shift was identified among 34 of the 35 studies reviewed. Effect sizes were reported in 17 studies assessing QoL outcomes among cancer patients; 12 of which had negligible to small effect sizes, four reported medium effect sizes which were related to physical, global QoL, pain, and social (role) functioning and one reported a large effect size (fatigue). The most prevalent method for assessing response shift was the then-test , which is prone to recall bias, followed by the pre-test and post-test method. Given the heterogeneity among the characteristics of the samples and designs reviewed, as well as the overall small to negligible effect sizes for the effects reported, conclusions stating that changes due to internal cognitive shifts in perceived QoL should account for changes observed in cancer patients' QoL outcomes should be interpreted with caution. Conclusion: Further work is needed in this area of research. Future studies should control for patient characteristics, time elapsed between diagnosis and baseline assessment and evaluate their contribution to the presence of response shift. Time between assessments should include short and longer periods between assessments and evaluate whether the presence of response shift holds over time. Possible avenues for inquiry for future investigation are discussed.

Quality of Life in Women Diagnosed with Breast Cancer after a 12-Month Treatment of Lifestyle Modifications

“…Patients were enrolled at differ-ent stages of cancer treatment which may have differently affected HRQoL. Although response-shift may affect quality of life outcomes [51] our study included patients enrolled within one year of surgery. At baseline only 16% of participants in the study were still receiving chemotherapy, 50% completed chemotherapy treatment and 34% did not receive chemotherapy treatment, therefore it is unlikely that chemotherapy influenced HRQoL significantly.…”

Mediterranean diet and quality of life in women treated for breast cancer: A baseline analysis of DEDiCa multicentre trial

“…Patients were enrolled at different stages of cancer treatment which may have differently affected HRQoL however we adjusted for cancer therapy. Although response-shift may affect quality of life outcomes [62], our study included patients enrolled within one year of surgery and time from surgery did not show any effect modification. We were also able to account for type of breast cancer surgery and for comorbidities which may both affect quality of life.…”

Positive association between physical outcomes and patient-reported outcomes in late-onset Pompe disease: a cross sectional study

“…As a result, patients may adapt to their situation over time and adjust their expectations [ 30 ], explaining the normal mental health scores. This phenomenon is called response shift, and is a recognized issue in studies of health-related quality of life amongst chronic patients, including cancer patients [ 31 , 32 ].…”