Assessing health state utilities for people with myalgic encephalomyelitis/chronic fatigue syndrome in Australia using the EQ-5D-5L, AQoL-8D and EQ-5D-5L-psychosocial instruments

PURPOSE

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic condition with a constellation of symptoms presenting as severe and profound fatigue of ≥ 6 months not relieved by rest. ME/CFS affects health-related quality of life (HRQoL), which can be measured using multi-attribute health state utility (HSU) instruments. The aims of this study were to quantify HSUs for people living with ME/CFS, and to identify an instrument that is preferentially sensitive for ME/CFS.

METHODS

Cross-sectional national survey of people with ME/CFS using the AQoL-8D and EQ-5D-5L. Additional questions from the AQoL-8D were used as 'bolt-ons' to the EQ-5D-5L (i.e., EQ-5D-5L-Psychosocial). Disability and fatigue severity were assessed using the De Paul Symptom Questionnaire-Short Form (DSQ-SF). HSUs were generated using Australian tariffs. Mean HSUs were stratified for sociodemographic and clinical factors. Bland-Altman plots were used to compare the three HSU instruments.

RESULTS

For the 198 participants, mean HSUs (95% confidence intervals) were EQ-5D-5L: 0.46 (0.42-0.50); AQoL-8D: 0.43 (0.41-0.45); EQ-5D-5L-Psychosocial: 0.44 (0.42-0.46). HSUs were substantially lower than population norms: EQ-5D-5L: 0.89; AQoL-8D: 0.77. As disability and fatigue severity increased, HSUs decreased in all three instruments. Bland-Altman plots revealed interchangeability between the AQoL-8D and EQ-5D-5LPsychosocial. Floor and ceiling effects of 13.5% and 2.5% respectively were observed for the EQ-5D-5L instrument only.

CONCLUSIONS

ME/CFS has a profound impact on HRQoL. The AQoL-8D and EQ-5D-5L-Psychosocial can be used interchangeably: the latter represents a reduced participant burden.

Health state utility and health-related quality of life measures in patients with advanced ovarian cancer

Purpose

Measuring health-related quality of life (HRQoL) in ovarian cancer patients is critical to understand the impact of disease and treatment. Preference-based HRQoL measures, called health state utilities, are used specifically in health economic evaluations. Real-world patient-reported data on HRQoL and health state utilities over the long-term course of ovarian cancer are limited. This study aims to determine HRQoL and health state utilities in different health states of ovarian cancer.

Methods

This cross-sectional, multicenter study included patients with stage III-IV ovarian cancer in six health states: at diagnosis, during chemotherapy, after cytoreductive surgery (CRS), after chemotherapy, in remission, and at first recurrence. HRQoL was measured using the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire C30, and the ovarian cancer-specific module OV28. Health state utilities were assessed using the EuroQol five-dimension five-level (EQ-5D-5L) questionnaire. Descriptive analyses were performed for each health state.

Results

Two hundred thirty-two patients participated, resulting in 319 questionnaires. Median age was 66 years. The lowest HRQoL was observed during chemotherapy and shortly after CRS. Physical and role functioning were most affected and the highest symptom prevalence was observed in the fatigue, nausea, pain, dyspnea, gastrointestinal, neuropathy, attitude, and sexuality domains. Patients in remission had the best HRQoL. Mean utility values ranged from 0.709 (±0.253) at diagnosis to 0.804 (±0.185) after chemotherapy.

Conclusions

This study provides clinicians with a valuable resource to aid in patient counseling and clinical decision-making. The utilities, in particular, are crucial for researchers conducting economic analyses to inform policy decisions.

Psychometric properties and comparison of four health utility approaches among myopia patients in China

BACKGROUND

The increased prevalence of myopia creates and earlier age of onset has created public health concerns for the long-term eye health, vision impairment and carries with it a significant economic burden. The quality of the economic evaluation is dependent on the sensitivity and validity of the approaches. Nowadays, there are many approaches to measure patients' health state utility (HSU). However, little is known regarding the performance of direct approach and indirect approach in people with myopia. This study is aimed to compare the psychometric properties of four HSU approaches among patients with myopia in mainland China, including two direct approaches (TTO and SG), the generic preference-based measures (PBM) (AQoL-7D) and the disease-specific PBM (VFQ-UI).

METHODS

A convenience sampling framework was used to recruit patients with myopia who attended a large ophthalmic hospital in Jinan, China. Spearman's rank correlations coefficient was used to assess concurrent validity. Known-group validity was analyzed by: (1) whether the patients wear corrective devices; (2) severity of myopia as low or moderate to high of the better eye; (3) duration of myopia as ≤ 10 years or > 10 years. Effect size (ES), relative efficiency (RE) statistic and the largest area under the receiver operating characteristic curve (AUC) were used to assess sensitivity. The intra-class correlation coefficient (ICC) and Bland-Altman plots were used to assess agreement.

RESULTS

A valid sample size of 477 myopia patients was analyzed (median duration: 10 years). The mean HSU scores between TTO and SG were similar (0.95) and higher than AQoL-7D (0.89) and VFQ-UI (0.83). Overall, the VFQ-UI had the best performance based on the psychometric analysis. The agreement indicated that there was no pair of approaches that could be used interchangeably.

CONCLUSIONS

The VFQ-UI showed better psychometric properties than other three approaches for providing health state utility in Chinese myopia patients. Given the widespread use and its generic nature of the AQoL-7D, it could be used alongside with VFQ-UI to provide complementary health state utility from a generic and disease-specific perspective for economic evaluation. More evidence on the responsiveness of four health utility approaches in myopia patients is required.

Health state utility estimation of Mycobacterium Avium complex pulmonary disease using a time trade-off approach

AIMS

To obtain appropriate health state utility values for cost-effectiveness analyses of new Mycobacterium avium complex pulmonary disease (MAC-PD) treatments. The impact of MAC-PD severity and symptoms on quality of life (QoL) also were quantified.

METHODS

A questionnaire describing four health states, MAC-positive severe, MAC-positive moderate, MAC-positive mild, and MAC-negative, was developed based on St. George's Respiratory Questionnaire (SGRQ) Symptom and Activity scores from the CONVERT trial. The time trade-off (TTO) method with ping-pong titration procedure was used to estimated health state utilities. Regression analyses assessed impacts of covariates.

RESULTS

Of 319 Japanese adults (49.8% female, mean age 44.8 years), mean (95% CI) health state utility scores (MAC-positive severe, MAC-positive moderate, MAC-positive mild, and MAC-negative) were 0.252 (0.194-0.310), 0.535 (0.488-0.582), 0.816 (0.793-0.839), and 0.881 (0.866-0.896), respectively. MAC-negative state utility scores were significantly higher than MAC-positive severe (mean difference [95% CI], 0.629 [0.574-0.684]), MAC-positive moderate (0.346 [0.304-0.389]), and MAC-positive mild (0.065 [0.048-0.082]) scores (p < 0.001 each). Most participants would trade survival duration to avoid MAC-positive states (97.5% to avoid MAC-positive severe; 88.7% MAC-positive moderate; 61.4% MAC-positive mild). Regression analyses to investigate the impact of background characteristics showed similar utility differences between health states when not adjusted for covariates.

LIMITATIONS

Some participant demographics differed from the general population; however, this did not impact utility differences among health states as regression analyses adjusting for demographics did not affect these differences. Similar investigations are needed among patients with MAC-PD and in other countries.

CONCLUSIONS

This study evaluating the impact of MAC-PD on utilities using the TTO method demonstrates that differences in utilities are dependent on the severity of respiratory symptoms and their impacts on daily activities and QoL. These results could contribute to better quantification of the value of MAC-PD treatments and improve assessments of cost-effectiveness.

Higher diet quality is associated with short and long-term benefits on SF-6D health state utilities: a 5-year cohort study in an international sample of people with multiple sclerosis

BACKGROUND/PURPOSE

Health state utilities (HSU) are a subjective measure of an individual's health-related quality of life (HRQoL), adjusted by societal or patient relative preference weights for living in different states of health-related quality of life (HRQoL), derived from patient-reported responses to multi-attribute utility instrument (MAUI), and can be used as inputs for cost-utility analyses and in clinical assessment. This research assessed associations of diet with subsequent HSU in a large international cohort of people living with multiple sclerosis (MS), a progressive autoimmune condition of the central nervous system.

METHODS

HSUs were generated from responses to Short-Form Six-Dimension (SF-6D) MAUI, and quality-of-the-diet by Diet Habits Questionnaire (DHQ). Cross-sectional, and short- and long-term prospective associations of DHQ with HSU evaluated by linear regression at 2.5- and 5-years. Pooled prospective associations between DHQ and HSU evaluated using linear and quantile regression. Analyses adjusted for relevant demographic and clinical covariates.

RESULTS

Among 839 participants, baseline DHQ scores showed short- and long-term associations with subsequent HSU, each 10-unit increase in total DHQ score associated with 0.008-0.012 higher HSU (out of 1.00). These associations were dose-dependent, those in the top two quartiles of baseline DHQ scores having 0.01-0.03 higher HSU at follow-up, 0.03 being the threshold for a minimally clinically important difference. Fat, fiber, and fruit/vegetable DHQ subscores were most strongly and consistently associated with better HSU outcomes. However, baseline meat and dairy consumption were associated with 0.01-0.02 lower HSU at subsequent follow-up.

CONCLUSIONS

A higher quality-of-the-diet showed robust prospective relationships with higher HSUs 2.5- and 5-years later, substantiating previous cross-sectional relationships in this cohort. Subject to replication, these results suggest interventions to improve the quality-of-the-diet may be effective to improve HRQoL in people living with MS.

Patient preferences and health state utilities associated with the treatment process of antiretroviral therapy for people living with HIV

PURPOSE

People living with HIV (PLHIV) have reported challenges associated with daily oral antiretroviral therapy (ART), including missed doses, negative psychological impact, and difficulty remaining discreet while at home or traveling. Recently approved long-acting injectable (LAI) ART may help eliminate these concerns. The purpose of this study was to examine patient preferences and estimate health state utilities associated with oral and LAI treatment for ART.

METHODS

Four health state vignettes were developed based on published literature, clinician interviews, and a pilot study. All vignettes included the same description of HIV, but differed in treatment regimens: (A) single daily oral tablet, (B) two daily oral tablets, (C) injections once monthly, and (D) injections every two months. PLHIV in the UK reported their preferences and valued the health states in time trade-off utility interviews.

RESULTS

The sample included 201 PLHIV (83.1% male; mean age = 44.9y). The health states frequently selected as most preferable were D (n = 119; 59.2%) and A (n = 75; 37.3%). Utility differences among health states were relatively small, which is typical for treatment process utilities (mean utilities: A, 0.908; B, 0.905; C, 0.900; D, 0.910). Statistically significant differences in utility were found for one vs. two tablets and injections every month vs. every two months (p < 0.001). Participants' quotations highlight the wide range of reasons for treatment process preferences.

CONCLUSIONS

Current results indicate that many PLHIV would prefer LAI ART. The reported utilities may be useful in economic modeling comparing oral vs. LAI ART.

Application of validated mapping algorithms between generic PedsQL scores and utility values to individuals with sickle cell disease

PURPOSE

There is a paucity of empirically estimated health state utility (HSU) values to estimate health-related quality of life among individuals with sickle cell disease (SCD). This study aims to map the Pediatric Quality of Life Inventory generic core scales (PedsQL GCS) to HSUs for children and adolescents with SCD in the United States, using published algorithms, and to assess the construct validity of these HSUs against SCD-specific PedsQL scores.

METHODS

We used the published mapping algorithms identified in four published articles, in which the PedsQL GCS was mapped to either the EuroQol-5 Dimension 3-Level, Youth Version or the Child Health Utility 9-Dimension to obtain HSUs. We employed the algorithms to calculate HSUs for a sample of children and adolescents from the Sickle Cell Clinical Research and Intervention Program. To assess the construct validity of the mapped HSUs in SCD patients, we computed Spearman's correlation coefficient comparing the HSUs with the PedsQL SCD total score and separately with each PedsQL SCD dimension-specific score.

RESULTS

The mean mapped HSU across published algorithms was 0.792 (95% CI: 0.782-0.801). It was significantly higher among children aged 5-12 years than children aged 13-17 years. The Spearman's correlation coefficient for HSUs versus PedsQL SCD total scores was 0.64 (95% CI: 0.57-0.71). Correlations ranged from 0.40 (95% CI: 0.32-0.48) to 0.60 (95% CI: 0.54-0.66) for HSUs versus PedsQL SCD dimension-specific scores.

CONCLUSIONS

The existing mapping algorithms show acceptable construct validity in children and adolescents with SCD. Additional algorithms are needed for adults and for specific SCD comorbidities.

Health Utility Measures Among Patients with Androgenetic Alopecia After Hair Transplant

BACKGROUND

Hair loss causes significant psychosocial distress to patients. Health utility measurements offer an objective, quantitative assessment of health-related quality of life (QOL).

METHODS

We performed a prospective cohort study on patients with hair loss between January 1, 2018 and December 31, 2020. Patient metrics were compared with layperson perception of alopecia, prospectively collected between August 1 and December 31, 2017. Health utility measures were quantified using the visual analog scale (VAS), standard gamble (SG), and time trade-off (TTO) in quality-adjusted life-years (QALYs) and relative to the minimal clinically important difference (MCID). Bonferroni correction to the significance threshold was performed.

RESULTS

Thirty-one patients with alopecia were compared with 237 laypeople. Patient metrics for female hair loss were all significantly lower than laypeople measures (VAS QALYs 0.65 ± 0.21 vs. 0.83 ± 0.18, p = 0.0001). Mean SG QALYs were lower for patients in the male alopecia state (0.86 ± 0.23 vs. 0.96 ± 0.12, p = 0.0278). Post-hair transplant improvement in TTO was significantly greater for patients (+ 0.08 ± 0.12 vs. + 0.02 ± 0.09, p = 0.0070) and significantly more often exceeded the MCID (45.2% vs. 16.9%, p = 0.0006).

CONCLUSIONS

Alopecia negatively impacts QOL, and the true patient experience is more taxing than what is perceived by laypeople. Hair transplantation improves QOL more for male patients than common perception.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Health state utility values by cancer stage: a systematic literature review

OBJECTIVES

Cancer diagnoses at later stages are associated with a decrease in health-related quality of life (HRQOL). Health state utility values (HSUVs) reflect preference-based HRQOL and can vary based on cancer type, stage, treatment, and disease progression. Detecting and treating cancer at earlier stages may lead to improved HRQOL, which is important for value assessments. We describe published HSUVs by cancer type and stage.

METHODS

A systematic review was conducted using Embase, MEDLINE^®, EconLit, and gray literature to identify studies published from January 1999 to September 2019 that reported HSUVs by cancer type and stage. Disutility values were calculated from differences in reported HSUVs across cancer stages.

RESULTS

From 13,872 publications, 27 were eligible for evidence synthesis. The most frequent cancer types were breast (n = 9), lung (n = 5), colorectal (n = 4), and cervical cancer (n = 3). Mean HSUVs decreased with increased cancer stage, with consistently lower values seen in stage IV or later-stage cancer across studies (e.g., - 0.74, - 0.44, and - 0.51 for breast, colorectal, and cervical cancer, respectively). Disutility values were highest between later-stage (metastatic or stage IV) cancers compared to earlier-stage (localized or stage I-III) cancers.

CONCLUSIONS

This study provides a summary of HSUVs across different cancer types and stages that can inform economic evaluations. Despite the large variation in HSUVs overall, a consistent decline in HSUVs can be seen in the later stages, including stage IV. These findings indicate substantial impairment on individuals' quality of life and suggest value in early detection and intervention.

Association between knee symptoms, change in knee symptoms over 6-9 years, and SF-6D health state utility among middle-aged Australians

OBJECTIVES

Health state utilities (HSUs) are an input metric for estimating quality-adjusted life-years (QALY) in cost-utility analyses. Currently, there is a paucity of data on association of knee symptoms with HSUs for middle-aged populations. We aimed to describe the association of knee symptoms and change in knee symptoms with SF-6D HSUs and described the distribution of HSUs against knee symptoms' severity.

METHODS

Participants (36-49-years) were selected from the third follow-up (completed 2019) of Australian Childhood Determinants of Adult Health study. SF-6D HSUs were generated from the participant-reported SF-12. Association between participant-reported WOMAC knee symptoms' severity, change in knee symptoms over 6-9 years, and HSUs were evaluated using linear regression models.

RESULTS

For the cross-sectional analysis, 1,567 participants were included; mean age 43.5 years, female 54%, BMI ± SD 27.18 ± 5.31 kg/m². Mean ± SD HSUs for normal, moderate, and severe WOMAC scores were 0.820 ± 0.120, 0.800 ± 0.120, and 0.740 ± 0.130, respectively. A significant association was observed between worsening knee symptoms and HSUs in univariable and multivariable analyses after adjustment (age and sex). HSU decrement for normal-to-severe total-WOMAC and WOMAC-pain was - 0.080 (95% CI - 0.100 to - 0.060, p < 0.01) and - 0.067 (- 0.085 to - 0.048, p < 0.01), exceeding the mean minimal clinically important difference (0.04). Increase in knee pain over 6-9 years was associated with a significant reduction in HSU.

CONCLUSION

In a middle-aged population-based sample, there was an independent negative association between worse knee symptoms and SF-6D HSUs. Our findings may be used by decision-makers to define more realistic and conservative baseline and ongoing HSU values when assessing QALY changes associated with osteoarthritis interventions.

Relationship between health-related quality of life and subjective wellbeing in asthma

OBJECTIVE

Poor health-related quality of life (HRQoL) is associated with a high risk of acute exacerbations in patients with asthma. The use of health state utility instruments to measure HRQoL is common, but it has been criticised for failing to adequately capture the impact of the condition from the patient perspective. We aimed to assess the ability of subjective wellbeing and health state utility instruments to capture important HRQoL dimensions for asthma patients.

METHODS

Regression analyses were conducted using data (n = 856 asthma patients) from a large multi-national cross-sectional survey to explore the relationship between subjective wellbeing (ONS4, PWI, SWLS), health state utility (15D, AQoL-8D, EQ-5D-5L, HUI3, SF-6D, SF-6Dv2), and an asthma-specific instrument (AQLQ-S). The latent structure of different instruments was investigated using an exploratory factor analysis.

RESULTS

All instruments could distinguish the impact of asthma on HRQoL. Among health utility instruments, 15D, SF-6D and AQoL-8D were more sensitive based on the average standardised regression coefficients. AQOL-8D had the strongest correlation with subjective wellbeing. Nevertheless, the exploratory factor analysis showed a complementary relationship between subjective wellbeing and HRQoL instruments. The most important subjective wellbeing domains were standard of living, achieving in life, and personal relationships; although contributions of these domains to overall life satisfaction differed among asthma patients identified by a latent class analysis.

CONCLUSION

The use of subjective wellbeing alongside AQLQ-S and health state utility instruments provides a comprehensive approach to assess the impact of asthma on the patient's life. Further research is needed to incorporate these measures in health care evaluation.

A mapping study in mainland China: predicting EQ-5D-5L utility scores from the psoriasis disability index

Aims: This study aims to develop a mapping algorithm that can be used to predict 5-level EQ-5D (EQ-5D-5L) utility scores from the Psoriasis Disability Index (PDI) for further use in cost-utility analysis among psoriasis patients.Materials and Methods: A total of 321 participants with psoriasis was recruited in a dermatology clinic from a tertiary hospital in China. The EQ-5D-5L utility scores were scored using the Chinese-specific value set. Three model specifications were used and each one was estimated using three different statistical techniques, including the ordinary least squares (OLS), the Tobit regression and the generalized linear model (GLM). The goodness-of-fit of mapping performance was estimated by using two common indicators: the mean absolute error (MAE) and the mean square error (MSE).Results: A final validated sample of 321 psoriasis patients was analyzed in the study. The patients had a mean ± standard deviation (SD) age of 39.7 ± 12.9 years, and the EQ-5D-5L state utility score is 0.899 ± 0.106. Among all the models considered, the OLS linear model based on the four PDI item scores was selected as the best model due to higher accuracy (MAE = 0.1334 and 0.1557 for the estimation and validation sample separately).Limitations: The main limitation of this study is that the survey site was limited to one hospital and not more broadly representing the whole of China. Additionally, there are some missing data in the full sample and an absence of an external dataset to validate the algorithms.Conclusions: The mapping algorithms reported in this paper can be used to predict the EQ-5D-5L utilities from the PDI; however, similar to other mapping studies in the literature it can only serve as the second-best approach to elicit utilities from disease-specific instruments.

Estimating health state utility from activities of daily living in the French National Hospital Discharge Database: a feasibility study with head and neck cancer

Background

Health state utility (HSU) is a core component of QALYs and cost-effectiveness analysis, although HSU is rarely estimated among a representative sample of patients. We explored the feasibility of assessing HSU in head and neck cancer from the French National Hospital Discharge database.

Methods

An exhaustive sample of 53,258 incident adult patients with a first diagnosis of head and neck cancer was identified in 2010–2012. We used a cross-sectional approach to define five health states over two periods: three "cancer stages at initial treatment" (early, locally advanced or metastatic stage); a "relapse state" and otherwise a "relapse-free state" in the follow-up of patients initially treated at early or locally advanced stage. In patients admitted in post-acute care, a two-parameter graded response model (Item Response Theory) was estimated from all 144,012 records of six Activities of Daily Living (ADLs) and the latent health state scale underlying ADLs was calibrated with the French EQ-5D-3 L social value set. Following linear interpolation between all assessments of the patient, daily estimates of utility in post-acute care were averaged by health state, patient and month of follow-up. Finally, HSU was estimated by health state and month of follow-up for the whole patient population after controlling for survivorship and selection in post-acute care.

Results

Head and neck cancer was generally associated with poor HSU estimates in a real-life setting. As compared to “distant metastasis at initial treatment”, mean HSU was higher in other health states, although numerical differences were small (0.45 versus around 0.54). It was primarily explained by the negative effects on HSU of an older age (38.4% aged ≥70 years in “early stage at initial treatment”) and comorbidities (> 50% in other health states). HSU estimates significantly improved over time in the “relapse-free state” (from 8 to 12 months of follow-up).

Conclusions

HSU estimates in head and neck cancer were primarily driven by age at diagnosis, comorbidities, and time to assessment of cancer survivors. This feasibility study highlights the potential of estimating HSU within and across severe conditions in a systematic way at the national level.

Electronic supplementary material

The online version of this article (10.1186/s12955-019-1195-9) contains supplementary material, which is available to authorized users.

Is the EQ-5D fit for purpose in asthma? Acceptability and content validity from the patient perspective

Background

The increasing emphasis on patient-reported outcomes in health care decision making has prompted greater rigor in the evidence to support the instruments used. Acceptability and content validity are important properties of any measure to ensure it assesses the relevant aspects of the target concept. The purpose of this study was to evaluate the acceptability and content validity of the EQ-5D 5-Level (EQ-5D-5L) to assess the impact of asthma on patients’ lives.

Methods

Qualitative interviews were conducted with 40 adults with asthma in the United Kingdom. The first 25 interviews used cognitive-debriefing methods to assess the relevance and acceptability of the EQ-5D-5L and two asthma-specific measures for comparison: an asthma-specific, preference-based measure (the Asthma Quality of Life Utility Index–5 Dimensions) and an Asthma Symptom Diary. The final 15 interviews combined concept elicitation to identify patient-perceived asthma impact, and cognitive debriefing to assess relevance and acceptability of the EQ-5D-5L and the Asthma Symptom Diary. Cognitive-debriefing feedback on the content of the measures was collated and summarized descriptively. The concept-elicitation data were analyzed thematically.

Results

Participants were aged 20 to 57 years and 62.5% were female. Although some participants expressed positive opinions on aspects of the EQ-5D-5L, only the usual activities dimension was consistently considered relevant to participants’ asthma experiences. The mobility and self-care dimensions prompted strong negative reactions from some participants. Variations in interpretation of the mobility dimension and difficulties with multiple concepts in the pain/discomfort and anxiety/depression dimensions also were noted. Concepts reported by participants as missing included environmental triggers, asthma symptoms, emotions, and sleep. The EQ-5D-5L was the least preferred measure to describe the impact of asthma on participants’ lives. Participants reported shortness of breath and impact on activities as especially salient issues.

Conclusions

The content of the EQ-5D-5L was poorly aligned with the patient-perceived impact of asthma, and the measure failed to meet basic standards for acceptability and content validity as a measure to assess the impact of asthma from the patient perspective. The shortcomings identified raise concerns regarding the appropriateness of the EQ-5D in asthma and further evaluation is warranted.

The validity of the SF-12 and SF-6D instruments in people living with HIV/AIDS in Kenya

Background

Health-related quality of life (HRQoL) and health state utility value (HSUV) measurements are vital components of healthcare clinical and economic evaluations. Accurate measurement of HSUV and HRQoL require validated instruments. The 12-item Short-Form Health Survey (SF-12) is one of few instruments that can evaluate both HRQoL and HSUV, but its validity has not been assessed in people living with HIV/AIDS (PLWHA) in east Africa, where the burden of HIV is high.

Methods

This cross-sectional study used baseline data from a randomized trial involving PLWHA in Kenya. Data included responses from a translated and adapted SF-12 survey as well as key demographic and clinical data. Construct validity of the survey was examined by testing the SF-12’s ability to distinguish between groups known in advance to have differences in their health based on their disease severity. We classified disease severity based on established definitions from the US Center for Disease Control (CDC) and WHO, as well as a previously studied viral load threshold. T-tests and ANOVA were used to test for differences in HRQoL and HSUV scores. Area under the receive operator curve (AUC) was used to test the discriminative ability of the HRQoL and HSUV instruments.

Results

Differences in physical component scores met the minimum clinically important difference among participants with more advanced HIV when defined by CD4 count (4.3 units) and WHO criteria (compared to stage 1, stages 2, 3 and 4 were 2.0, 7.2 and 9.8 units lower respectively). Mental score differences met the minimum clinically important difference between WHO stage 1 and stage 4 patients (4.4). Differences in the HSUV were statistically lower in more advanced HIV by all three definitions of severity. The AUC showed poor to weak discriminatory ability in most analyses, but had fair discriminatory ability between WHO clinical stage 1 and clinical stage 4 individuals (AUC = 0.71).

Conclusion

Our findings suggest that the Kiswahili translated and adapted version of the SF-12 could be used as an assessment tool for physical health, mental health and HSUV for Kiswahili-speaking PLHWA.

Trial registration

Clinical trials.gov identifier: NCT00830622. Registered 26 January 2009.

Establishing benchmark EQ-5D-3L population health state utilities and identifying their correlates in Gansu Province, China

PURPOSES

Despite a flurry of cost utility analyses conducted in the Chinese population in recent years, a standard set of health state utilities (HSUs) for the Chinese population is lacking. The aims of this study were to (1) determine benchmark age- and sex-specific HSUs for a Chinese population, and (2) assess key correlates of HSUs in this population.

METHODS

Quality-of-life was evaluated using the validated EQ-5D-3L questionnaire. HSUs were calculated using data collected from Gansu Province (n = 9833). Overall differences in HSUs were analysed using linear regression and a two-tailed p value <0.05 was determined to be statistically significant. The minimal difference in weighted index was set at 0.074.

RESULTS

HSUs decreased with age in both males and females. Living in the non-capital areas, being separated/divorced/widowed or never married, being never educated, diagnosed with chronic disease, and no regular physical activity were associated with lower HSUs. HSUs for women were lower than for men in univariate regression analysis; however, no differences were found after adjusting for other covariates. In addition, the difference in HSU reached the level of minimal difference in weighted index for participants with chronic disease. HSUs for those who were diagnosed with chronic disease were 0.098 (0.092-0.104) lower than those without chronic disease.

CONCLUSIONS

This study reports HSUs for a Chinese population in Gansu and investigates the key correlates of HSUs in this population. In addition, the use of EQ-5D-3L in assessing population health is limited given the high ceiling effect and skewed HSUs.