Development, feasibility, and validity of a computer-based utility assessment tool for measuring asthma-specific health utilities in Malaysia using the standard gamble method

Validity and Responsiveness of EQ-5D in Asthma: A Systematic Review and Meta-analysis

OBJECTIVE

We aimed to synthesize the evidence on the construct validity and responsiveness of the EQ-5D and compare them with asthma-specific health-related quality-of-life scales, to guide further research and clinical applications in asthma.

METHODS

We searched key databases from inception to 1 June, 2024 and used the COnsensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) method to appraise the evidence. The effect size estimates were aggregated using the inverse variance method to evaluate the relative efficiency of EQ-5D measures against the Asthma Quality of Life Questionnaire (AQLQ) and/or its corresponding preference-based index, Asthma Quality of Life-5 Dimensions (AQL-5D).

RESULTS

There were 493 tests (construct validity: 428; responsiveness: 65) drawn from 37 selected articles (validation: 7; clinical: 30). Overall, 78.4% and 76.9% of the a priori hypotheses for assessing construct validity (convergent validity: 56.4%; known groups: 88.5%) and responsiveness, respectively, were satisfied. The methodological quality was "very good" or "adequate" in 78.2% of construct validity tests and 92.3% of responsiveness tests. The pooled correlation coefficient between EQ-5D index and AQLQ total scores was 0.52 (95% confidence interval 0.43-0.59), and between EQ visual analog scale and AQLQ total scores was 0.53 (95% confidence interval 0.34-0.69). The Cohen's d ratios for the index, level sum scores, and visual analog scale compared to AQLQ were 0.56 (n = 27), 1.16 (n = 16), and 0.75 (n = 37). The EQ-5D index's Cohen's d ratio compared to AQL-5D was 0.49 (n = 5). The standardized response mean ratios for the index and visual analog scale compared to AQLQ were 0.26 (n = 11) and 0.63 (n = 9).

CONCLUSIONS

The EQ-5D demonstrated overall good validity and responsiveness in the adult asthma population. However, a comparison against disease-specific instruments suggested scope for improvement in its psychometric performance for this population.

Use of the visual analogue scale for health state valuation: a scoping review

OBJECTIVES

The visual analogue scale (VAS) has been used in the context of health and healthcare for various purposes, for example, to measure pain and to provide a single-index measure of health-related quality of life (HRQoL). This scoping review aims to describe how the VAS has been used for health state valuation in the published literature.

METHODS

The search was carried out in Medline, Web of Science and PsycInfo. The findings of the included articles were tabulated and presented descriptively using frequencies and proportions.

RESULTS

The database search yielded 4856 unique articles, out of these, 308 were included. In 83% of the articles, the main purpose for using a VAS was to value health states. The two most common perspectives when valuing health states with a VAS were hypothetical (44%) and own health (34%). Some (n = 14) articles used the VAS in the context of economic evaluations, including calculating quality-adjusted life years (QALYs). A large variation in the design of the VAS was found, including the description of the lower and upper anchors. Advantages and disadvantages with using a VAS were mentioned in 14% of the included articles.

CONCLUSION

The VAS has been a common method for valuing health states, both as a stand-alone method and in combination with other valuation methods. Despite its widespread use, the design of the VAS has been inconsistent which makes comparison of results across studies challenging. Further research on the role of using the VAS in economic evaluations is warranted.

Health-related quality of life in adult patients with asthma according to asthma control and severity: A systematic review and meta-analysis

Background: The utility values are increasingly being used in economic evaluations and health policy decision making. This study aims to conduct a systematic literature review and meta-analysis of the utility values for asthma, particularly with respect to severity and asthma control. Materials and methods: A literature search was conducted using the MEDLINE, Embase, and Cochrane Central Register of Controlled Trials databases for studies published until July, 2020, reporting the utilities of adult asthma. We extracted utility values derived by nine indirect and four direct utility instruments. Meta-analyses were performed for each utility instrument according to health states based on the level of asthma control and severity. Results: Fifty-two eligible studies were included in our systematic review, of which forty studies were used in the meta-analyses. Among the 13 utility instruments, the most used was EQ-5D-3L, whereas EQ-5D-5L showed the narrowest 95% confidence interval (95% CI, 0.83-0.86) of pooled utility. The pooled utility of asthma declined with worsening control levels and severity. The pooled utility value of EQ-5D-3L was 0.72 (95% CI, 0.63-0.80) for uncontrolled, 0.82 (95% CI, 0.75-0.88) for partly controlled, and 0.87 (95% CI, 0.84-0.90) for well-controlled asthma. Conclusion: Our study shows that EQ-5D-3L and EQ-5D-5L are appropriate for economic evaluations in terms of availability and variability of information, respectively. Asthma patients had poorer utility values with worsened severity and level of asthma control. This study will be useful for health economists conducting economic evaluations of asthma treatments.

Automated Tool for Health Utility Assessments: The Gambler II

Background. The Gambler II is a web-based utility assessment tool supporting visual analogue scale (VAS), standard gamble (SG), and time trade-off (TTO) utility assessments. It contains novel features, including an easy to use project development authoring tool and use of multimedia clips for health state descriptions. Objectives. Evaluate the usability and understandability of the patient-facing side of The Gambler. Investigate the feasibility of using The Gambler and evaluate its impact on patient knowledge regarding the relevant health states. Materials and Methods. We used The Gambler to assess utilities on a convenience sample of 55 users for common long-term complications of type 2 diabetes mellitus: diabetic neuropathy, diabetic retinopathy, and diabetic foot infection requiring transmetatarsal amputation. Using VAS, SG, and TTO, we collected metadata, such as time spent on each assessment and the entire assessment process. We evaluated usability with an adaptation of the System Usability Scale survey and understandability. We evaluated impact on knowledge gained through knowledge assessments about these complications before and after use of The Gambler. Results. Overall satisfaction with The Gambler was high, 4.02 on a 5-point scale. Usability rated highly at 84.93 on a normalized scale between 0 and 100. Knowledge scores increased significantly following use of The Gambler from pretest mean of 68% to posttest mean of 76% (P < 0.01). Average time using the software: ∼7½ minutes. Conclusions. The Gambler is an easy to use and understand computer-based tool for utility assessment. It is feasible to use within clinical encounters to support shared decision making, and it has unique features that make it a powerful tool for investigators interested in research on health utilities.

Direct Assessment of Health Utilities Using the Standard Gamble Among Patients With Primary Intracerebral Hemorrhage

BACKGROUND

Standard gamble (SG) directly measures patients' valuation of their health state. We compare in-hospital and day-90 SG utilities (SGU) among intracerebral hemorrhage patients and report a 3-way association between SGU, EuroQoL-5 dimension, and modified Rankin Scale at day 90.

METHODS AND RESULTS

Patients with intracerebral hemorrhage underwent in-hospital and day-90 assessments for the modified Rankin Scale, EuroQoL-5 dimension, and SG. SG provides patients a choice between their current health state and a hypothetical treatment with varying chances of either perfect health or a painless death. Higher SGU (scale, 0-1) indicates lower risk tolerance and thus higher valuation of the current health state. Logistic regression was used to estimate the likelihood of low SGU (≤0.6), and Wilcoxon paired signed-rank test compared in-hospital and day-90 SGU. In-hospital and day-90 SG was obtained from 381 and 280 patients, respectively, including 236 paired observations. Median (interquartile range) in-hospital and day-90 SGUs were 0.85 (0.40-0.98) and 0.98 (0.75-1.00; P<0.001). In-hospital SGUs were lower with advancing age (P=0.007), higher National Institutes of Health Stroke Scale, and intracerebral hemorrhage scores (P<0.001). Proxy-based assessments resulted in lower SGUs; median difference (95% CI), -0.2 (-0.33 to -0.07). After adjustment, higher National Institutes of Health Stroke Scale and proxy assessments were independently associated with lower SGU, along with an effect modification of age by race. Day-90 SGU and modified Rankin Scale were significantly correlated; however, SGUs were higher than the EuroQoL-5 dimension utilities at higher modified Rankin Scale levels.

CONCLUSIONS

Divergence between directly (SGU) and indirectly (EuroQoL-5 dimension) assessed utilities at high levels of functional disability warrant careful prognostication of intracerebral hemorrhage outcomes and should be considered in designing early end-of-life care discussions with families and patients.

Using a dynamic adherence Markov model to assess the efficiency of Respiratory Medication Therapy Adherence Clinic (RMTAC) on asthma patients in Malaysia

Background

Respiratory Medication Therapy Adherence Clinic (RMTAC) is an initiative by the Ministry of Health (MOH) Malaysia to improve patients’ medication adherence, as an adjunct to the usual physician care (UC). This study aimed to evaluate the cost-effectiveness of combined strategy of RMTAC and UC (RMTAC + UC) vs. UC alone in asthma patients, from the MOH Malaysia perspective.

Methods

A lifetime horizon dynamic adherence Markov model with monthly cycle was developed, for quality-adjusted life year (QALY) gained and hospitalization averted outcomes. Transition probabilities of composite asthma control and medication adherence, utilities, costs, and mortality rates due to all causes were measured from local data sources. Effectiveness, exacerbation rates, and asthma mortality rates were taken from non-local data sources. One-way sensitivity analysis (SA) was conducted for assessing parameter uncertainties, whereas probabilistic SA (PSA) was conducted on a different set of utilities and effectiveness data. Costs were adjusted to 2014 US dollars ($). Both costs and benefits were discounted at a 3% rate annually.

Results

RMTAC + UC was found to be a dominant alternative compared to UC alone; $− 13,639.40 ($− 109,556.90 to $104,445.54) per QALY gained and $− 428.93 ($− 521.27 to ($− 328.69)) per hospitalization averted. These results were found to be robust against changes in all parameters except utilities in the one-way SA, and for both scenarios in PSA.

Conclusions

RMTAC + UC is more effective and yet cheaper than UC alone, from the MOH perspective. For the benefit of both MOH and patients, RMTAC is thus recommended to be remained, and expanded to more healthcare settings where possible.

Electronic supplementary material

The online version of this article (10.1186/s12962-018-0156-1) contains supplementary material, which is available to authorized users.

Validity of a Chinese version of the Mini Asthma Quality of Life Questionnaire (MiniAQLQ) and a comparison of completion by patients and relatives

OBJECTIVE

To test the psychometric properties of the Chinese version of the Mini Asthma Quality of Life Questionnaire (MiniAQLQ) and to investigate the differences between the MiniAQLQ completed by patients (p-MiniAQLQ) and by their relatives (r-MiniAQLQ).

METHODS

One hundred and two asthmatic patients and 45 relatives were recruited. The reliability was evaluated using Cronbach's alpha and intraclass correlation coefficient (ICC). The validity of the MiniAQLQ was assessed by comparing it with the Sydney Asthma Quality of Life Questionnaire (AQLQ-S) and lung function measurements. The mean quality of life scores were compared by gender and smoking history, and the p-MiniAQLQ scores were then compared with the r-MiniAQLQ scores.

RESULTS

The MiniAQLQ showed high internal consistency (Cronbach's alpha = 0.901) and a high two-week reproducibility (ICC = 0.863). The cross-sectional correlations between the MiniAQLQ and the AQLQ-S were strong. Correlations between the MiniAQLQ and lung function (predicted FEV1% and PEF) ranged from poor to weak at the total or domain levels. The MiniAQLQ scores were not significantly associated with gender or smoking history. There was poor agreement between the p-MiniAQLQ and r-MiniAQLQ scores at the total or domain levels.

CONCLUSIONS

The Chinese version of the MiniAQLQ showed good reliability and validity. It is reliable for evaluating the impact of asthma on patients' quality of life. Relatives of the patients did not have a comprehensive grasp of the patients' conditions. Physicians should be cautious when patients' relatives come to the hospital to seek a modified treatment when the patients are not present.