Preferences for improvements in attributes associated with basal insulin: a time trade-off and willingness-to-pay survey of a diabetic and non-diabetic population in Sweden

Health state utilities associated with weight loss: preferences of people with type 2 diabetes and obesity in Japan

AIMS

Health state utilities associated with weight change are needed for cost-utility analyses (CUAs) examining the value of treatments for type 2 diabetes and obesity. Previous studies have estimated the utility benefits associated with various amounts of weight reduction in the US and Europe, but preferences for weight change in Asian cultures may differ from these published values. The purpose of this study was to estimate utilities associated with reductions in body weight based on preferences of individuals with type 2 diabetes and obesity in Japan.

METHODS

Health state vignettes represented type 2 diabetes with respondents' own current weight and weight reductions of 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, and 20%. Utilities were elicited in time trade-off interviews with a sample of respondents in Japan with type 2 diabetes and body mass index (BMI) ≥25 kg/m2 (the cutoff for obesity in Japan).

RESULTS

Analyses were conducted with data from 138 respondents (84.8% male; mean age = 58.0 years; mean BMI = 29.4 kg/m2) from all eight regions of Japan. Utility gains gradually increased with rising percentage of weight reductions ranging from 2.5% to 15%. Weight reductions of 2.5% to 15% resulted in utility increases of 0.013 to 0.048. The health state representing a 20% weight reduction yielded a wide range of preferences (mean utility increase of 0.044). Equations are recommended for estimating utility change based on any percentage of weight reduction (up to 20%) in Japanese people with type 2 diabetes and obesity.

LIMITATIONS

This study was conducted in a sample with limited representation of patients with BMI >35 kg/m2 (n = 13) and relatively few women (n = 21).

CONCLUSION

Results may be used to provide inputs for CUAs examining the value of treatments that are associated with weight loss in patients with type 2 diabetes and obesity in Japan.

The impact on quality of life of diet restrictions and disease symptoms associated with phenylketonuria: a time trade-off and discrete choice experiment study

Phenylketonuria (PKU) is a metabolic disorder leading to a deficiency in the metabolism of phenylalanine (Phe). Elevated Phe levels in the blood, tissue and brain may lead to emotional, cognitive, and physical symptoms in adults. To control blood Phe levels, most individuals with PKU need to follow a strict, life-long Phe-restricted diet. The main objective of this study was to estimate the impact of PKU-related disease symptoms and dietary restrictions on health-related quality of life (HRQoL). This study was designed as a web-based survey using the methods of Time Trade-Off (TTO) and Discrete Choice Experiment with duration (DCE_TTO) in a survey of the Swedish general population and population with PKU. Data were collected using questionnaires for TTO diet (n = 509), TTO symptoms (n = 507), and DCE_TTO (n = 1117). The disutility of diet restrictions ranged from 0.050 for a partially restricted diet without medical food to 0.193 for a fully restricted diet with medical food in the TTO (DCE: 0.043-0.108). The disutility of experiencing symptoms (emotional, cognitive and physical) ranged from 0.148 for mild symptoms to 0.593 for severe symptoms in the TTO (DCE: 0.122-1.522). The study shows that both diet and symptoms have a significant negative impact on HRQoL in PKU and that utility estimates are largely consistent across methods and samples.

Evaluating the Impact of Therapy on Quality of Life in Type 2 Diabetes: A Literature Review of Utilities Associated with Treatment-Related Attributes

Introduction

Treatment-related attributes and process characteristics such as dosing frequency, timing flexibility, ease of use of injection devices and unpleasant side-effects may have small but measurable effects on quality of life (QoL) in people with type 2 diabetes (T2D). A literature review was performed to identify recently published utility values quantifying the effect of treatment-related attributes on QoL.

Methods

Literature search strategies were designed using high-level medical subject heading (MeSH) terms supplemented with free-text terms and searches were run in March 2020 in the PubMed, Embase and Cochrane Library databases. For inclusion, studies were required to be published in full-text form, in English, since 2010 and report utility values (elicited using either direct or indirect methods) for treatment-related attributes or process characteristics including side effects, change in weight/body mass index (BMI), dosing frequency and timing flexibility, device attributes (e.g. needle handling, requirement for reconstitution) and convenience (e.g. waiting time).

Results

A total of 30 studies were included in the review, of which all but three were conducted in people with T2D. The EQ-5D was the most commonly used elicitation method (fourteen studies), followed by time tradeoff (TTO) methodology. Treatment-related adverse events and inconveniences such as needle handling in administration devices and waiting time were consistently associated with lower QoL, whereas lower dosing frequency and increased timing flexibility with dosing were consistently associated with utility benefits. The relationship between change in BMI and QoL was non-linear and influenced by baseline BMI.

Conclusion

Treatment-related attributes and process characteristics are associated with minor changes in QoL, which should be taken into account in long-term health economic modeling of new treatments and administration devices.

Health state utilities associated with weight loss in type 2 diabetes and obesity

INTRODUCTION

Health state utilities associated with weight change are needed as inputs for cost-utility analyses (CUAs) examining the value of treatments for obesity and type 2 diabetes (T2D). Although some pharmaceutical treatments currently in development are associated with substantial weight loss, little is known about the utility impact of weight decreases greater than 10%. The purpose of this study was to estimate utilities associated with body weight decreases up to 20% based on preferences of individuals with obesity, with and without T2D.

METHODS

Health state vignettes were developed to represent respondents' own current weight and weight decreases of 2.5, 5, 10, 15, and 20%. Health state utilities were elicited in time trade-off interviews in two UK locations (Edinburgh and London) with a sample of participants with obesity, with and without T2D. Mean utility increases associated with each amount of weight decrease were calculated. Regression analyses were performed to derive a method for estimating utility change associated with weight decreases.

RESULTS

Analyses were conducted with data from 405 individuals with obesity (202 with T2D, 203 without T2D). Utility increases associated with various levels of weight decrease ranged from 0.011 to 0.060 in the subgroup with T2D and 0.015 to 0.077 in the subgroup without T2D. All regression models found that the percentage of weight decrease was a highly significant predictor of change in utility (p < .0001). The relationship between weight change and utility change did not appear to be linear. Equations are recommended for estimating utility change based on the natural logarithm of percentage of weight decrease.

DISCUSSION

Results of this study may be used to provide inputs for CUAs examining and comparing the value of treatments that are associated with substantial amounts of weight loss in patients with obesity, with or without T2D.

The Psychometric Properties of a Self-Administered, Open-Source Module for Valuing Metastatic Epidural Spinal Cord Compression Utilities

INTRODUCTION

Web surveys are often used for utility valuation. Typically, custom utility valuation tools that have not undergone psychometric evaluation are used.

OBJECTIVES

This study aimed to determine the psychometric properties of a metastatic epidural spinal cord compression (MESCC) module run on a customizable open-source, internet-based, self-directed utility valuation platform (Self-directed Online Assessment of Preferences [SOAP]).

METHODS

Individuals accompanying patients to the emergency department waiting room in Ottawa, Canada, were recruited. Participants made SOAP MESCC health state valuations in the waiting room and 48 h later at home. Validity, agreement reliability, and responsiveness were measured by logical consistency of responses, smallest detectable change, the interclass correlation coefficient, and Guyatt's responsiveness index, respectively.

RESULTS

Of 285 participants who completed utility valuations, only 113 (39.6%) completed the re-test. Of these 113 participants, 92 (81.4%) provided valid responses on the first test and 75 (66.4%) provided valid responses on the test and re-test. Agreement for all groups of health states was adequate, since their smallest detectable change was less than the minimal clinically important difference. The mean interclass correlation coefficients for all health states were > 0.8, indicating at least substantial reliability. Guyatt's responsiveness indices all exceeded 0.80, indicating a high level of responsiveness.

CONCLUSIONS

To our knowledge, this is the first validated open-source, web-based, self-directed utility valuation module. We have demonstrated the SOAP MESCC module is valid, reproducible, and responsive for obtaining ex ante utilities. Considering the successful psychometric validation of the SOAP MESCC module, other investigators can consider developing modules for other diseases where direct utility valuation is needed.

A Computer-Assisted Personal Interview App in Research Electronic Data Capture for Administering Time Trade-off Surveys (REDCap): Development and Pretest

Background

The time trade-off (TTO) task is a method of eliciting health utility scores, which range from 0 (equivalent to death) to 1 (equivalent to perfect health). These scores numerically represent a person’s health-related quality of life. Software apps exist to administer the TTO task; however, most of these apps are poorly documented and unavailable to researchers.

Objective

To fill the void, we developed an online app to administer the TTO task for a research study that is examining general public proxy health-related quality of life estimates for persons with Alzheimer’s disease. This manuscript describes the development and pretest of the app.

Methods

We used Research Electronic Data Capture (REDCap) to build the TTO app. The app’s modular structure and REDCap’s object-oriented environment facilitated development. After the TTO app was built, we recruited a purposive sample of 11 members of the general public to pretest its functionality and ease of use.

Results

Feedback from the pretest group was positive. Minor modifications included clarity enhancements, such as rearranging some paragraph text into bullet points, labeling the app to delineate different question sections, and revising or deleting text. We also added a research question to enable the identification of respondents who know someone with Alzheimer’s disease.

Conclusions

We developed an online app to administer the TTO task. Other researchers may access and customize the app for their own research purposes.

Preference-based valuation of treatment attributes in haemophilia A using web survey

INTRODUCTION

Clinical trials have shown promising results for extended half-life factor VIII concentrates but little is known about individuals' valuation of haemophilia treatment attributes.

AIM

To assess patient/caregiver and population valuation of treatment attributes of prophylactic regimens for people with severe haemophilia A.

METHODS

Members ≥16 years of the Swedish Haemophilia Society (FBIS) and of a web-panel representative of the Swedish population were invited to participate in a web-survey investigating preferences for haemophilia treatment attributes using the Time Trade-Off methodology which ranks health states on a scale 0 (dead) to 1 (full health). All respondents assessed the same four treatment scenarios for severe haemophilia A, each described by three stylized attributes: injection interval (every 2nd or 5th day); participation in physical activity (Y/N); annual risk of bleed (1-2 or 5-6 bleeds).

RESULTS

The survey had 1657 respondents (68% complete responses; 184/1233 from FBIS/web-panel gave informed consent; mean age 52 years, 51% men). Respondents from FBIS and from the web-panel had the same preference ranking of the four treatment scenarios, but members of FBIS consistently rated significantly higher health utilities; range 0.67-0.73 vs 0.54-0.60. Participation in physical activity implied +0.023 (95% confidence interval 0.015-0.030); a longer injection interval implied +0.038 (0.03; 0.45); and fewer bleeds implied +0.022 (0.015-0.029) utility points.

CONCLUSIONS

Patient/caregiver and population preferences indicate that treatment attributes such as frequency of injections and the possibility of participating in physical activity are important attributes impacting quality of life in addition to the control and prevention of bleeding episodes.