Ateesha F. Mohamed

Treatment preferences and medication adherence of people with Type 2 diabetes using oral glucose-lowering agents

Aims  Medication non‐adherence is particularly common in patients with Type 2 diabetes. We constructed a discrete‐choice experiment to examine the relative importance of oral glucose‐lowering medication features and to estimate the likely effect of effectiveness and side effects on medication adherence in patients with Type 2 diabetes in the UK and the USA.

Patients’ preferences for treatment outcomes for advanced non-small cell lung cancer: A conjoint analysis

BACKGROUND 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. METHODS 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. RESULTS 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. CONCLUSION 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.

Patient Benefit-Risk Preferences for Targeted Agents in the Treatment of Renal Cell Carcinoma

Background: Angiogenesis inhibitor agents have been shown to be effective in increasing progression-free survival (PFS) in patients with renal cell carcinoma (RCC); however, these treatments have different toxicity profiles. Objective: Our objective was to quantify patients’ benefit-risk preferences for RCC treatments and relative importance of attributes in a common metric.Methods: US residents aged ≥18 years with RCC completed a web-enabled, choice-format conjoint survey that presented a series of 12 trade-off questions, each including a pair of hypothetical RCC treatment profiles. Each profile was defined by efficacy (PFS, when overall survival held constant), tolerability effects (fatigue/tiredness, diarrhoea, hand-foot syndrome [HFS], mouth sores) and serious adverse events (liver failure, blood clot). Trade-off questions were based on a predetermined experimental design with known statistical properties. Random-parameters logit was used to analyse the data.Results: A total of 138 patients completed the survey. PFS was the most important attribute for patients over the range of levels included in the survey, while remaining attributes were ranked in decreasing order of importance: fatigue/tiredness, diarrhoea, liver failure, HFS, blood clot and mouth sores. In order to increase PFS by 11 months, patients would be willing to accept a maximum level of absolute blood clot risk of 3.1%(95%CI 1.5, 5.3) or liver failure risk of 2.0% (95% CI 1.0, 3.3).Conclusion: A 22-month change in PFS was shown to be the most important improvement for patients. Severe fatigue/tiredness and diarrhoea were rated as the most troublesome tolerability effects of RCC treatment. Patients were likely willing to accept significant treatment-related risks of 2–3% for liver failure and blood clot to increase PFS by 11 months.

Patient preferences and assessment of likely adherence to hepatitis C virus treatment

Summary.  To estimate patient preferences for attributes of hepatitis C virus (HCV) treatment and patients’ assessment of the likely effect of treatment attributes on treatment adherence, HCV patients ≥18 years old completed an online survey that included nine 2‐alternative choice questions. Each choice question was defined by the probability of sustained viral response (Efficacy), injection frequency (Frequency), duration of flu‐like symptoms after every injection (Flu), injection device (Device), average number of days of work missed each week (Lost Work Days), probability of reversible hair thinning while on treatment (Alopecia) and probability of developing clinical depression while on treatment (Depression). We estimated a mean relative importance weight for each attribute. Patients also answered three rating questions to assess the extent to which treatment attributes might affect adherence. Hundred and fifty patients completed the survey. Efficacy was the most important attribute with a mean relative importance weight of 10 [95% CI: 7.9–12.1]. The remaining attributes were ranked in order of importance as follows: Depression (4.4 [95% CI: 3.6–5.1]), Flu Days (Frequency × Flu) (3.7 [95% CI: 2.2–5.3]), Lost Work Days (2.9 [95% CI: 2.3–3.5]), Alopecia (1.3 [95% CI: 0.7–1.9]) and Device (1.2 [95% CI: 0.4–2.0]). Patients with prior treatment experience were less likely to indicate that treatment attributes would affect adherence. Patients also indicated that increases in the number of flu days would increase the likelihood of nonadherence to treatment. Sustained viral response is the most important treatment attribute to patients but treatment side effects might affect treatment adherence.

Public preferences for the return of research results in genetic research: a conjoint analysis

Purpose:Recent policies specifying criteria about which individual research results to return leave considerable discretion to researchers. This study investigated the types of results that the public wants when participating in genetic research and whether preferences differ based on willingness to participate.Methods:A representative survey of US adults used conjoint analysis to measure priorities among eight principles of a results policy for a proposed large-cohort study. Policy preferences were measured using 12 tasks in which respondents chose between two groupings of the policy principles. Stratified analysis compared those self-identified as likely or unlikely to participate in genomic research.Results:Of 1,515 respondents, 56% would participate in the proposed study. All eight principles were positively endorsed by participants (all P < 0.003), with priority placed on providing results at no cost and returning well-validated results for treatable and serious diseases. Providing detailed result reports was more highly valued than providing staff to explain results (P = 0.0005). Receiving results about major changes in risk was marginally disvalued by those unlikely to participate (P = 0.35).Conclusion:Public preferences for well-validated individual research results for serious, actionable diseases agree with emerging recommendations. However, because preferences for receiving individual research results vary, some choices should be offered to research participants.Genet Med 16 12, 932–939.

Patients rank toxicity against progression free survival in second-line treatment of advanced renal cell carcinoma

Abstract Background: The aims of this study were to quantify and contrast patient preferences between second-line advanced renal cell carcinoma (RCC) medication profiles and their associated benefits and toxicities, and to help frame the doctor–patient discussion about selecting appropriate RCC therapies. Research design and methods: Adult residents of the US with a diagnosis of RCC completed a Web-enabled choice-format conjoint survey consisting of a series of 10 treatment-choice questions, each of which included a pair of hypothetical RCC medication profiles. Each profile was described by various medication attributes (features or outcomes) with varying levels. The attributes included efficacy (progression-free survival [PFS]), tolerability (fatigue, stomach problems, mucositis or stomatitis, hand–foot syndrome [HFS]), serious but rare adverse events (pneumonitis, hepatic impairment), and mode of administration. Treatment-choice questions were based on an experimental design with known statistical properties. Random-parameters logit regression was used to estimate relative preference weights for each attribute level. Benefit equivalent measures (additional months of PFS in exchange for toxicities) were also calculated. Results: Of the 272 patients who completed the survey, the majority were female (53%), white (92%), and had at least a college degree (66%). The mean age was 57 years (standard deviation: 10 years). Over the range of attributes and attribute levels included in the survey, PFS was the most important attribute, followed by fatigue, stomach problems, hepatic impairment, mucositis or stomatitis, HFS, pneumonitis, and mode of administration. To reduce severe fatigue to mild-to-moderate fatigue, patients on average would be willing to forego 4.4 months of PFS. To reduce hepatic impairment risk from 0.5% to 0.0%, patients on average would be willing to forego 1.0 month of PFS. The main study limitation was that patients answered hypothetical treatment-choice questions. Conclusions: This study provides information to physicians about patient priorities when reviewing and selecting RCC therapies with patients.

Who pays attention in stated-choice surveys?

Responses of inattentive or inconsistent subjects in stated-choice (SC) surveys can lead to imprecise or biased estimates. Several SC studies have investigated inconsistency and most of these studies dropped subjects who were inconsistent. However, none of these studies reported who is more likely to fail consistency tests. We investigated the effect of the personal characteristics and task complexity on preference inconsistency in eight different SC surveys. We found that white, higher-income and better-educated female subjects were less likely to fail consistency tests. Understanding the characteristics of subjects who are inattentive to the choice task may help in designing and pre-testing instruments that work effectively for a wider range of subjects.

How do physicians weigh benefits and risks associated with treatments in patients with osteoarthritis in the United Kingdom

Objective. To quantify the relative importance that UK physicians attach to the benefits and risks of current drugs when making treatment decisions for patients with osteoarthritis (OA). Methods. Physicians treating at least 10 patients with OA per month completed an online discrete-choice experiment survey and answered 12 treatment-choice questions comparing medication profiles. Medication profiles were defined by 4 benefits (reduction in ambulatory pain, resting pain, stiffness, and difficulty doing daily activities) and 3 treatment-related risks [bleeding ulcer, stroke, and myocardial infarction (MI)]. Each physician made medication choices for 3 of 9 hypothetical patients (varied by age, history of MI, hypertension, and history of gastrointestinal bleeding). Importance weights were estimated using a random-parameters logit model. Treatment-related risks physicians were willing to accept in exchange for various reductions in ambulatory and resting pain also were calculated. Results. The final sample was 475. A reduction in ambulatory pain from 75 mm to 25 mm (1.6 units) was 1.1 times as important as an increase in MI risk from 0% to 1.5% (1.5 units). The greatest importance was for eliminating a 3% treatment-related risk of MI or stroke. On average, physicians were willing to accept an increase in bleeding ulcer risk of 0.7% (95% CI 0.4%–1.7%) for a reduction in ambulatory pain of 75 mm to 50 mm. Conclusion. When presented with well-known benefits and risks of OA treatments, physicians placed greater importance on the risks than on the analgesic properties of the drug. This has implications for the reporting of the results of clinical research to physicians.

Patient preferences and linear scoring rules for patient reported outcomes.

AbstractBackground: Many patient-reported outcomes (PRO) instruments are scored by averaging or summing Likert category values over all items or domains of the elicitation instrument, yielding domain-specific scores or a total score for the entire instrument. Objective: To evaluate differences between conventional linear and preference-weighted scores for PRO instruments used in asthma, oncology, and obesity. Methods: We estimated preference-weighted scores for all the items and response categories in the Onset-of-Effect Questionnaire (OEQ), the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ)-C30, and the Impact of Weight on Quality of Life Questionnaire-Lite version (IWQOL-Lite) using choice-format conjoint analysis, known also as discrete-choice experiments. Results: Conventional linear scoring rules can overstate the relative importance to patients of improvements in some domains and understate the relative importance of improvements in other domains. Conclusions: Patient preference-weighted scores estimated by conjoint-analysis methods allow for non-linearities and account for the relative contribution of individual items and domains to patient well-being. Conventional linear scores and preference-weighted scores can result in different conclusions about the size of patient-reported treatment effects.

Evaluation of the relative importance of chemotherapeutic and antiemetic efficacy in various oncologic settings

Goals of workThis study investigated physician’s attitudes toward the relative importance of chemotherapeutic and antiemetic efficacy in different clinical scenarios.Materials and methodsOncologists in the USA and four European countries completed an online stated-choice survey consisting of three hypothetical treatment choices for each of two patient types. Each hypothetical treatment alternative included both chemotherapy and antiemetic regimens. The two hypothetical patient types were (1) a 48-year-old woman with locoregional infiltrating ductal carcinoma of the breast and (2) a 78-year-old man with squamous cell carcinoma of the lung and multiple liver metastases. In each choice question, oncologists were asked to select the better combination of chemotherapy and antiemetic prophylaxis between two treatment alternatives.Main resultsFive hundred fifty-seven oncologists completed the survey. For the adjuvant breast cancer patient, the most aggressive chemotherapy is consistently the most important treatment consideration in all countries. For the advanced lung cancer patient, the most aggressive chemotherapy, the less aggressive chemotherapy, and the most aggressive antiemetic prophylaxis are of similar importance in most countries.ConclusionsPhysicians appear more likely to prescribe a more aggressive chemotherapy regimen for a younger patient with a perceived curable tumor, regardless of the emetogenic properties of the chemotherapy. Symptom management is more of a concern and chemotherapeutic efficacy relatively less of a priority in an older patient with advanced disease for whom chemotherapy is not curative.