This study reviewed articles that evaluated the response shift among patients with end-stage renal disease. In the four included studies, “then-test” was most commonly employed. Though response shift was proved existent or even significant in all studies, due to statistical approaches, we were unable to obtain the details about the significance testing. In two of three longitudinal studies, QoL had been assessed twice and the interval time was three months. More assessment should be considering in the future studies, such as setting additional time points and periods, to investigate the change of RS over time [14, 26]. Except for one study in which the initial QoL assessment was conducted before the kidney transplantation [17], the other three studies all included patients that had already received dialysis for several months in the baseline [11, 15–16]. Considering that patients may report a high level of response shift in their primary stage after diagnosis and in a short time after first treatment [27], response shift assessment should be administered at the time of diagnosis and the initial treatment in future research. Besides, patients with dialysis were the most commonly enrolled populations in the four included studies. Given that renal replacement therapy modalities among patients with ESRD are various and have remarkable impacts on patients-reported quality of life [7, 28–29], the RS mechanism among patients with different RRT modalities need to be compared and discussed.
It is crucial to assess the presence and magnitude of response shift because it may cover up the real change of QoL and provide information about how the patients get used to disease. A study conducted in patients receiving pancreas-kidney transplantation revealed that their re-evaluated QoL after a successful transplantation was significantly lower than the prospective assessment before the transplantation, indicating that patients with chronic disease had an excellent capacity to adapt to their conditions [30]. A deeper understanding of RRT treatment's psychological impact may help patients live with ESRD better [12]. This finding can be used to avoid negative RS and induce positive RS, thus helping patients recognize the change in health status and signal of recovery [31]. Therefore, more well-designed studies should be to conduct to deepen the understanding of response shift among patients with ESRD.
There are two common methods for response shift detection [25]. One is design-based approaches, including retrospective pre-test design and individualized measures, which was widely used in the four reviewed articles. The other is model-based statistical approaches, such as structural equation model (SEM) method, relative importance analysis, and item response theory. A review conducted by Sajobi et al. reported an increasing number of sophisticated empirical methods in RS detection [22]. The advanced statistical purposes get rid of the recall bias of design-based approaches and are widely used in secondary longitudinal–data analyses, which we hope will be utilized in more studies among patients with ESRD. Distinguishing and correlating response shift at the group level and the individual level is another critical issue [32]. Sawatzky R thought the individual differences of RS could be regarded as heterogeneity because the presence and forms of RS varied in people [33]. In the theoretical model of RS of Sprangers M et al., antecedents such as personality and spiritual practice are among the five important elements of RS [3]. However, as an individual phenomenon, the response shift is usually identified at a group level through the quantitative statistical methods [31]. To solve this problem, Aburub AS et al. proposed to add a qualitative measure in the quantitative study to enhance the finding of RS [34]. On all accounts, when deciding RS detection methods, factors such as research aims, sample characteristics and variable disruptions should be considered.
As for the factors of response shift, Barbara et al. showed the impact of disease trajectory [11]. The study reported four themes of patients on dialysis in different stages, which included “the primary adjustment”, “thriving”, “surviving” and “end-stage. The changes of themes indicated their evident response shift as the health status and circumstances changed. The conclusion was similar to that of Yang J et at., which found that the patients with Parkinson's disease recalled their HRQoL differently according to their disease trajectory, and that the retrospective QoL assessments between “decliners” and “improvers” was different [35]. Besides, Liu, Nai Chih et al. revealed that have-want discrepancy was another catalyst of the response shift mechanism. Further research should focus more on patients with high have-want discrepancy and discuss how to encourage them to change their goals and life center.
As the previous research revealed, PRO has played a role in weighing up costs and benefits of therapeutic regimen, improving satisfaction, enhancing communication, and engaging patients in successfully shared decision making [36–38]. The need to better understand how diseases and treatment impact patients' lives, wellbeing and functional performance is well acknowledged [39–40]. However, the psychometric robustness to measure PRO may influence PRO's credibility and interfere with its effects [41], which is also required for more scientific rigor by The US Food and Drug Administration [42]. Self-reported HRQoL is an example of PRO assessment based on patients' perception of their physical, social, and mental wellbeing under the impact on their health condition or medical treatment [43]. Some researchers viewed response shift as an unintentional side effect of PRO instruments [25] and how it influenced the HRQoL assessment. It depends on the complexity of target complexity and the construct dimensionality of tools [44]. Designing an HRQoL instrument with the bias of RS eliminated may be a straightforward countermeasure. Still, when we view inducing RS as an intervention for psychological adjustment, it’s better to design a method to examine the effects of RS [44]. Shared decision-making (SDM) provides a new form of RS intervention. It stresses the self-evaluation and preferences of patients and may contribute to explaining the impact of RS and improving the use of PRO [45]. To our knowledge, studies intervening in response shift are few and have never been done among patients with ESRD. Notably, the intervening measure to response shift such as SDM or psychological counseling may help patients better adapt to illness and break the natural coping mechanism such as changing treatment or rebuilding their belief in life. Thus, the disclosure and explanation of key information, including potential consequences, should be provided to patients.
Our study is the first systematic review of the response shift among patients with ESRD. It may contribute to more focus on the study of RS in the context of ESRD. Optimized research design, advanced RS detection methods and effective intervention programs should be developed in this area. Some limitations of this systematic review should also be noted. First, we included studies in Chinese but excluded other foreign language papers according researcher’s own language background. Thus, some potentially relevant studies in other languages may be missed in the search of electronic databases (PubMed, EMBASE, EBSCO host, Web of Science, and Cochrane Library) and manual review. What’s more, all of the four included studies chose “then-test” to detect their response shift, which may be influenced by the recall bias. The interference of recall bias may be exceptionally substantial in the study conducted by Barbara et al., in which patients had been on dialysis for an average of 34 months [11].