Valuation and preliminary validation of the Greek 15D in a sample of patients with coronary artery disease

Determinants of health-related quality of life of patients with type 2 diabetes and multimorbidity: a cross-sectional study

PURPOSE

To examine the determinants of health-related quality of life (HRQoL) of patients with type 2 diabetes (PwD) and multimorbidity (MM) (at least one co-occurring condition besides T2D) among sociodemographic, disease-related, and MM variables and the association of MM with therapeutic targets.

METHODS

A total of 179 PwD attending primary care (PC) in Greece answered the 15 dimension HRQoL (15D) questionnaire between August 2019 and October 2020. Sociodemographic, disease-related, and MM characteristics were recorded. MM was categorized as concordant or discordant based on whether or not it was related to the pathophysiology of T2D. Independent predictors of the 15D score were examined in stepwise regression models among sociodemographic, disease-related, and MM variables and the association of MM with glycated hemoglobin (A1C) and low-density lipoprotein cholesterol (LDL-C) was assessed.

RESULTS

The mean 15D score was 0.85 ± 0.11 and the mean MM count was 4.3 ± 1.8. Significant predictors of a higher 15D score were male gender, married state, higher monthly income, and more physical activity. Significant predictors of a lower 15D score were employment, depression, musculoskeletal disease, coronary artery disease, neuropathy, and MM count, but discordant had a stronger effect than concordant MM. Increasing MM count was not significantly correlated with A1C and was correlated with lower LDL-C.

CONCLUSION

Non-medical (physical activity and sociodemographic) rather than disease-related characteristics and discordant more than concordant co-occurring conditions affected HRQoL of multimorbid PwD who did not have worse (A1C) or achieved better (LDL-C) therapeutic targets. A generalist approach to the non-medical needs and overall health conditions of PwD could be promoted in PC within the social determinants of health and MM.

Translation, Cultural Adaptation, and Reliability of the 15D Portuguese Version: A Generic Health-Related Quality of Life (HRQoL) Instrument

(1) Background: Purpose: The assessment of quality of life is essential to the human condition and can be measured through questionnaires. This study aims to translate and culturally adapt the 15D questionnaire to assess the population's quality of life, as well as explore its relative reliability and internal consistency; (2) Methods: The translation and cultural adaptation of the 15D questionnaire was carried out independently, considering two translations. The synthesis version was applied to eight subjects, distributed by gender. Cognitive interviews were conducted to observe clarity, acceptability, and familiarity with the version of the questionnaire. The final version of the questionnaire, in Portuguese, was again translated into the official language by two translators who had never had contact with the questionnaire. To assess the test-retest reliability and internal consistency of the 15D questionnaire, 43 participants were interviewed; (3) Results: Participants indicated that they had some doubts about dimensions, breathing, and discomfort and symptoms; however, as there were no suggestions for change, the questionnaire had no changes. Items were clear and understandable. Internal consistency was observed using Cronbach's alpha, with values between 0.76 and 0.98. The test-retest reliability values were between 0.77 and 0.97; and (4) Conclusions: The Portuguese version of the 15D questionnaire was proved to be equivalent to the English version and to be reliable for the Portuguese population. This instrument is easy to access and apply.

Multiple Sclerosis Patients Valuing Their Own Health Status: Valuation and Psychometric Properties of the 15D

An ongoing debate on decision and cost-utility analyses is whether to use preferences of general public or patients. The aim of this study was to replicate the valuation procedure of the multi-attribute utility generic measure, 15D, using a sample of multiple sclerosis (MS) patients and to assess its psychometric properties. Consecutive outpatient MS patients were recruited from two MS centers in Greece. The three-stage valuation procedure was applied and, with the use of elicited preference weights, an MS patients' algorithm was developed. The original Finnish value set derived from healthy individuals was also used to calculate scores and a comparison between the two algorithms was made. A total of 64 MS patients were evaluated. The 15D scores obtained with the MS patients' valuation algorithm were higher than the original one. The derived utilities differed significantly with respect to age, depressive symptoms, Expanded Disability Status Scale score and clinical form. MS patients indicated as most important domains mobility, mental functioning and vitality. Cronbach's alpha was estimated 0.876 and correlations between relevant dimensions of the instruments were moderate to high. The 15D was generally feasible and reliable in patients with MS and the valuation system yielded acceptable psychometric properties.

Exclusion Criteria in National Health State Valuation Studies: A Systematic Review

BACKGROUND

Health state valuation data are often excluded from studies that aim to provide a nationally representative set of values for preference-based health-related quality of life (HRQoL) instruments. The purpose was to provide a systematic examination of exclusion criteria used in the derivation of societal scoring algorithms for preference-based HRQoL instruments.

METHODS

Data sources included MEDLINE, official instrument websites, and publication reference lists. Analyses that used data from national valuation studies and reported a scoring algorithm for a generic preference-based HRQoL instrument were included. Data extraction included exclusion criteria and associated justifications, exclusion rates, the characteristics of excluded respondents, and analyses that explored consequential implications of exclusion criteria on the respective national tariff.

RESULTS

Seventy-six analyses (from 70 papers) met the inclusion criteria. In addition to being excluded for logical inconsistencies, respondents were often excluded if they valued fewer than 3 health states or if they gave the same value to all health states. Numerous other exclusion criteria were identified, with varying degrees of justification, often based on an assumption that respondents did not understand the task or as a consequence of the chosen statistical modeling techniques. Rates of exclusion ranged from 0% to 65%, with excluded respondents more likely to be older, less educated, and less healthy. Limitations included that the database search was confined to MEDLINE; study selection focused on national valuation studies that used standard gamble, time tradeoff, and/or visual analog scale techniques; and only English-language studies were included.

CONCLUSION

Exclusion criteria used in national valuation studies vary considerably. Further consideration is necessary in this important and influential area of research, from the design stage to the reporting of results.

Development of the Japanese 15D instrument of health-related quality of life: verification of reliability and validity among elderly people

OBJECTIVE

The 15D is a self-administered questionnaire for assessment of health-related quality of life, which contains 15 questions with 5 response options each. This study was conducted to evaluate the reliability and validity of the Japanese 15D.

METHODS

The subjects were 430 community-dwelling elderly people. Each item of the 15D was scored on a 5-point Likert scale, with level 1 being the best, score 1. Reliability was assessed by determination of the internal consistency and test-retest reliability. Criterion-based validity was assessed using the Japanese version of the Nottingham Health Profile (NHP) and Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG index). Acceptability was assessed by inquiring about the time required to complete the questionnaire and the burden felt in responding to it.

RESULTS

The answers of 423 individuals who responded to all items were analyzed. The median time required to complete the questionnaire was 5.0 minutes, and the proportion of subjects who indicated that the questionnaire was easy to complete was 98.3%. The Cronbach's alpha coefficients for all 15 items in the 2 surveys were 0.793 and 0.792, respectively. The intraclass correlation coefficients for the 15 items ranged from 0.44 to 0.72. In the relationship between the 15D and the NHP, the correlation coefficients between the corresponding domains were higher than those between non-corresponding domains. The prevalence of disability in higher-level functional capacity was higher in the "level 2 to 5" group than in the "level 1" group.

CONCLUSIONS

The Japanese version of the 15D showed sufficient internal consistency and moderate repeatability. Because of the short time required to complete the Japanese 15D and the significant relationships between the scores on the 15D and the NHP, and between the 15D and higher-level functional capacity, the acceptability and validity of the Japanese 15D were considered to be sufficient.

Psychometric and factor analytic evaluation of the 15D health-related quality of life instrument: the case of Greece

PURPOSE

To investigate the dimensionality, construct validity in the form of factorial, convergent, discriminant, and known-groups validity, as well as scale reliability of the fifteen dimensional (15D) instrument.

METHODS

15D data were collected from a large Greek general population sample (N = 3,268) which was randomly split into two halves. Data from the first sample were used to examine the distributional properties of the 15 items, as well as the factor structure adopting an exploratory approach. Data from the second sample were used to perform a confirmatory factor analysis of the 15 items, examine the goodness of fit of several measurement models, and evaluate reliability and known-groups validity of the resulting subscales, along with convergent and discriminant validity of the constructs.

RESULTS

Exploratory factor analysis, using a distribution-free method, revealed a three-factor solution of the 15D (functional ability, physiological needs satisfaction, emotional well-being). Confirmatory factor analysis provided support for the three-factor solution but suggested that certain modifications should be made to this solution, involving freeing certain elements of the matrix of factor loadings and of the covariance matrix of measurement errors in the observed variables. Evidence of convergent validity was provided for all three factors, but discriminant validity was supported only for the emotional well-being construct. Scale reliability and known-groups validity of the resulting three subscales were satisfactory.

CONCLUSIONS

Our results confirm the multidimensional structure of the 15D and the existence of three latent factors that cover important aspects of the health-related quality of life domain (physical and emotional functioning). The implications of our results for the validity of the 15D and suggestions for future research are outlined.

Comparing the sensitivity of EQ-5D, SF-6D and 15D utilities to the specific effect of diabetic complications

OBJECTIVES

Diabetes patients suffer from comorbid conditions and disease-related complications. Combined with demographic, clinical and treatment satisfaction variables, they have a confounding effect on health-related quality of life (HRQoL). This study compared the sensitivity of EQ-5D, SF-6D and 15D utilities to the specific effect of diabetes complications.

METHODS

Utilities were compared in 319 type II diabetics with and without comorbidities and complications. Based on subsample size and confirmed diagnoses, coronary heart disease (CHD) and diabetic retinopathy (DR) were two complications chosen for further analysis. Significant EQ-5D, SF-6D and 15D predictors were identified with OLS regression and subsequently controlled for with ANCOVA.

RESULTS

The presence of CHD resulted in utility decrements (P < 0.001) for all instruments, whereas DR only decreased 15D utilities (P < 0.05). Gender, age, treatment satisfaction, arthropathy and diabetic foot were significant predictors throughout, whereas BMI, neuropathy and CHD for at least two utilities. After controlling for these confounding variables, 15D still discriminated between diabetics with and without CHD (P < 0.01) and DR (P < 0.05), with seven and five dimensions affected, respectively.

CONCLUSIONS

After removing the effect of background variables, 15D utilities remain sensitive to CHD and DR. The obvious explanation is its richer descriptive system, which provides increased discriminative ability compared to EQ-5D and SF-6D, and this might be evidence for preferring the 15D in economic evaluations of interventions for diabetics. However, the need remains for further testing in other diabetes complications and more diverse patient samples.

Systematic Review and Empirical Comparison of Contemporaneous EQ-5D and SF-6D Group Mean Scores

Background. Group mean estimates and their underlying distributions are the focus of assessment for cost and outcome variables in economic evaluation. Research focusing on the comparability of alternative preference-based measures of health-related quality of life has typically focused on analysis of individual-level data within specific clinical specialties or community-based samples. Purpose. To explore the relationship between group mean scores for the EQ-5D and SF-6D across the utility scoring range. Methods. Studies were identified via a systematic search of 13 online electronic databases, a review of reference lists of included papers, and hand searches of key journals. Studies were included if they reported contemporaneous mean EQ-5D and SF-6D health state scores. All (sub)group comparisons of group mean EQ-5D and SF-6D scores identifiable from text, tables, or figures were extracted from identified studies. A total of 921 group mean comparisons were extracted from 56 studies. The nature of the relationship between the paired scores was examined using ranked scatter graphs and analysis of agreement. Results. Systematic differences in group mean estimates were observed at both ends of the utility scale. At the lower (upper) end of the scale, the SF-6D (EQ-5D) provides higher mean utility estimates. Conclusions. These findings show that group mean EQ-5D and SF-6D scores are not directly comparable. This raises serious concerns about the cross-study comparability of economic evaluations that differ in the choice of preference-based measures, although the review focuses on 2 of the available instruments only. Further work is needed to address the practical implications of noninterchangeable utility estimates for cost-per-QALY estimates and decision making.