Can Patients Diagnosed with Schizophrenia Complete Choice-Based Conjoint Analysis Tasks?

Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
The patient (Impact Factor: 1.9). 12/2011; 4(4):267-75. DOI: 10.2165/11589190-000000000-00000
Source: PubMed


Schizophrenia is a severe mental illness associated with hallucinations, delusions, apathy, poor social functioning, and impaired cognition. Researchers and funders have been hesitant to focus efforts on treatment preferences of patients with schizophrenia because of the perceived cognitive burden that research methods, such as conjoint analysis, place on them.
The objective of this study was to test if patients diagnosed with schizophrenia were able to complete a choice-based conjoint analysis (often referred to as discrete-choice experiments) and to test if meaningful trade-offs were being made.
German outpatients diagnosed with schizophrenia were eligible to participate in this study if they were aged 18-65 years, had received treatment for at least 1 year and were not experiencing acute symptoms. Conjoint analysis tasks were based on six attributes, each with two levels, which were identified via a literature review and focus groups. A psychologist in a professional interview facility presented each respondent with the eight tasks with little explanation. All interviews were recorded, transcribed, and analyzed to verify that respondents understood the tasks. Preferences were assessed using logistic regression, with a correction for clustering.
We found evidence that the 21 patients diagnosed with schizophrenia participating in the study could complete conjoint analysis tasks in a meaningful way. Patients not only related to the scenarios presented in conjoint tasks, but explicitly stated that they used their own preferences to judge which scenarios were better. Statistical analysis confirmed all hypotheses about the attributes (i.e. all attributes had the expected sign). Having a supportive physician, not feeling slowed, and improvements in stressful situations (p < 0.01) were the most important attributes.
We found that patients diagnosed with schizophrenia can complete conjoint analysis tasks, that they base their decisions on their own preferences, and that patients make trade-offs between attributes.

8 Reads
  • Source
    • "As respondents may be in an earlier disease stage, profiles were presented in the third person for two patients who were receiving treatment for advanced NSCLC. This use of the third person has successfully been used to prevent bias from the respondent's own experience [33] [34]. An example choice task is presented in Fig. 1. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Treatment decisions for advanced non-small cell lung cancer (NSCLC) are complex and require trade-offs between the benefits and risks experienced by patients. We evaluated the benefits that patients judged sufficient to compensate for the risks associated with therapy for NSCLC. Participants with a self-reported diagnosis of NSCLC (n=100) were sampled from an online panel in the United Kingdom. Eligible and consenting participants then completed a self-administered online survey about their disease and their treatment preferences were assessed. This involved respondents choosing among systematically paired profiles that spanned eight attributes: progression-free survival [PFS], symptom severity, rash, diarrhoea, fatigue, nausea and vomiting, fever and infection, and mode of treatment administration (infusion and oral). A choice model was estimated using mixed-logit regression. Estimates of importance for each attribute level and attribute were then calculated and acceptable tradeoffs among attributes were explored. A total of 89 respondents (73% male) completed all choice tasks appropriately. Increases in PFS together with improvements in symptom severity were judged most important and increased with PFS benefit - 4 months: 5.7; 95% CI: 3.5-7.9; 5 months: 7.1; 95% CI: 4.4-9.9; and 7 months: 10.0; 95% CI: 6.1-13.9. However, improvements in PFS were viewed as most beneficial when disease symptoms were mild and as detrimental when patients had severe symptoms. Fatigue (5.0; 95% CI: 2.7-7.3) was judged to be the most important risk, followed by diarrhoea (2.8; 95% CI: 0.7-4.9), nausea and vomiting (2.1; 95% CI: 0.1-4.1), fever and infection (2.1; 95% CI: 0.2-4.1), and rash (2.0; 95% CI: 0.2-3.9). Oral administration was preferred to infusion (1.8; 95% CI: 0.0-3.6). Patients with mild and moderate symptoms traded PFS for less risks or more convenience if the severe symptoms were not experienced. This study demonstrates the value of conjoint analysis in the study of patient preferences for cancer treatments. In this small sample of patients with NSCLC from the UK, we demonstrate that the value of improvements in PFS is conditional upon the severity of disease symptoms; and that risks are valued differently.
    Lung cancer (Amsterdam, Netherlands) 02/2012; 77(1):224-31. DOI:10.1016/j.lungcan.2012.01.016 · 3.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background While much discussion has been placed on the problem of poor compliance in the treatment of schizophrenia, there has been little discussion on the concordance between patients and psychiatrists, an important contributing factor to patient-centred care. Objective To estimate the concordance between patients’ and psychiatrists’ (ordinal and cardinal) valuations of multiple goals for schizophrenia treatment and to illustrate the utility of the self-explicated method in valuing a large number of treatment goals. Design Twenty treatment goals were identified during focus groups and literature review and were presented to patients and psychiatrists during structured interviews. Respondents were asked to rank the multiple treatment goals and rate them on a 5-point Likert scale. Three scores were calculated based on the ranking (1–20), rating (Likert scale) (1–5) and a self-explicated method estimated as the product of rating and ranking score (1–100). Concordance was tested using Spearman’s rho for overall ordinal rankings and via anova and F-test for the cardinal values assigned to a specific treatment goal. Participants A total of 105 outpatients diagnosed with schizophrenia and 160 psychiatrists in Germany. Results Patient and psychiatrist values were concordant when the ordinal properties of their valuations were assessed by rating (ρ = 0.63; P = 0.002), ranking (ρ = 0.51; P = 0.02) and self-explicated methods (ρ = 0.54; P = 0.01). Significant discordances were found when comparing the cardinal value placed on any given treatment goal using all three approaches, but the self-explicated method produced a more discerning statistic. Relative to patients, psychiatrists significantly (P < 0.05) overvalued reduced lack of emotion, improved sexual pleasure and improved communication while undervaluing reuptake of activities of daily living, improved satisfaction and recovered capacity for work. Conclusions While there is an overall concordance between patients’ and psychiatrists’ valuation, significantly different valuations on specific goals can be identified. Here, psychiatrists tend to focus on ‘textbook’ outcomes, while patients are more concerned with functioning and living a normal life. This study also demonstrates the importance of comparing the concordance in treatment goals and the importance of preference-based methods, such as the self-explicated method, in the study of concordance.
    Health expectations: an international journal of public participation in health care and health policy 06/2011; 16(2). DOI:10.1111/j.1369-7625.2011.00704.x · 3.41 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Decision making in knee osteoarthritis, with many treatment options, challenges patients and physicians alike. Unfortunately, physicians cannot describe in detail each treatment's benefits and risks. One promising adjunct to decision making in osteoarthritis is adaptive conjoint analysis (ACA). OBJECTIVE: To obtain insight into the experiences of elderly patients who use adaptive conjoint analysis to explore treatment options for their osteoarthritis. DESIGN: Participants, all 65 and older, completed an ACA decision aid exploring their preferences with regard to the underlying attributes of osteoarthritis interventions. We used focus groups to obtain insight into their experiences using this software. RESULTS: Content analysis distributed our participants' concerns into five areas. The predicted preferred treatment usually agreed with the individual's preference, but our participants experienced difficulty in four other domains: the choices presented by the software were sometimes confusing, the treatments presented were not the treatments of most interest, the researchers' claims about treatment characteristics were unpersuasive and cumulative overload sometimes developed. CONCLUSION: Adaptive conjoint analysis presented special challenges to our elderly participants; we believe that their relatively low level of computer comfort was a significant contributor to these problems. We suggest that other researchers choose the software's treatments and present the treatment attributes with care. The next and equally vital step is to educate participants about what to expect, including the limitations in choice and apparent arbitrariness of the trade-offs presented by the software. Providing participants with a sample ACA task before undertaking the study task may further improve participant understanding and engagement.
    Health expectations: an international journal of public participation in health care and health policy 09/2012; 17(6). DOI:10.1111/j.1369-7625.2012.00811.x · 3.41 Impact Factor
Show more