Developing an early childhood oral health impact-specific health-state classification system for a new preference-based instrument, the ECOHIS-4D

Health utility attributable to oral conditions in Japanese adults

OBJECTIVE

Utility values enable relative comparisons across various health conditions, providing information for efficient allocation of healthcare resources. This study aimed to (1) quantify the utility values attributable to oral health-related quality of life (OHRQoL) in Japanese adults and (2) develop models for converting the 14-item Oral Health Impact Profile (OHIP-14) scores into EuroQoL 5-dimension 5-level (EQ-5D-5L)-based utility values.

METHODS

This was a cross-sectional study. Data from a large-scale Internet survey of Japanese adults conducted in 2022 (n = 28 405; mean age 48.2 years) were analysed. Multiple linear regression models were fitted to investigate the association between OHIP-14 scores and EQ-5D-5L-based utility values, adjusting for confounders. Conversion models were developed using a random half of the participants, and the observed and predicted utility values in the other half were compared to evaluate the model performance.

RESULTS

Among the participants, 55.2% scored 0, 20.9% scored 1-5 and 23.9% scored 6-56 on the OHIP-14, corresponding mean utility values of 0.93, 0.90 and 0.84, respectively. A one-point increase in the OHIP-14 score was associated with a lower utility value (coefficient: -0.0053; 95% confidence interval:health-related quality of life -0.0056, -0.0051). The estimated utility value attributable to OHIP-14 was -23.3 per 1000 individuals, greater than that for other prevalent chronic conditions, including hypertension and diabetes (-2.9 and -7.1 per 1000 individuals, respectively). The conversion model incorporated the OHIP-14 total score, age, sex and self-rated health, predicted utility scores on average and captured differences according to the number of teeth lost. However, there was a discrepancy between predicted and observed utility values in the lower utility value groups.

CONCLUSION

OHRQoL substantially impacted utility values at the population level. The OHIP-14 holds the potential as a valuable tool for predicting average utility values based on oral health conditions; however, the prediction performance was relatively low for individuals with a lower health-related quality of life.

A scoping review to create a framework for the steps in developing condition-specific preference-based instruments de novo or from an existing non-preference-based instrument: use of item response theory or Rasch analysis

BACKGROUND

There is no widely accepted framework to guide the development of condition-specific preference-based instruments (CSPBIs) that includes both de novo and from existing non-preference-based instruments. The purpose of this study was to address this gap by reviewing the published literature on CSPBIs, with particular attention to the application of item response theory (IRT) and Rasch analysis in their development.

METHODS

A scoping review of the literature covering the concepts of all phases of CSPBI development and evaluation was performed from MEDLINE, Embase, PsychInfo, CINAHL, and the Cochrane Library, from inception to December 30, 2022.

RESULTS

The titles and abstracts of 1,967 unique references were reviewed. After retrieving and reviewing 154 full-text articles, data were extracted from 109 articles, representing 41 CSPBIs covering 21 diseases or conditions. The development of CSPBIs was conceptualized as a 15-step framework, covering four phases: 1) develop initial questionnaire items (when no suitable non-preference-based instrument exists), 2) establish the dimensional structure, 3) reduce items per dimension, 4) value and model health state utilities. Thirty-nine instruments used a type of Rasch model and two instruments used IRT models in phase 3.

CONCLUSION

We present an expanded framework that outlines the development of CSPBIs, both from existing non-preference-based instruments and de novo when no suitable non-preference-based instrument exists, using IRT and Rasch analysis. For items that fit the Rasch model, developers selected one item per dimension and explored item response level reduction. This framework will guide researchers who are developing or assessing CSPBIs.

Comparison of the Early Childhood Oral Health Impact Scale (ECOHIS-4D) and Child Health Utility Index (CHU-9D) in children with oral diseases

OBJECTIVE

Accurate assessment of child oral health is important for guiding economic evaluations and informing healthcare decision-making. Early Childhood Oral Health Impact Scale (ECOHIS-4D) is a preference-based instrument that measures the oral health-related quality of life of young children. The aim of this study was to compare the utility scores of ECOHIS-4D and Child Health Utility Index (CHU-9D), against an oral health indicator to evaluate which utility score corresponds better with the oral health indicator.

METHOD

The ECOHIS-4D and CHU-9D were applied to 314 parent/child dyads from preschools in a primary healthcare setting in Perth, Western Australia. Four parameters were used to assess which instrument corresponds better with the oral health indicator (decayed, missing and filled teeth score-dmft score): (i) discrimination, the ability to discriminate between different clinical severity groups, (ii) external responsiveness, how much the utility values relate to the changes in dmft scores, (iii) correlation, the association between the two instruments and the related dimensions and (iv) differences in the utility values across the two instruments.

RESULTS

Most participants (81%) were 2-6 years old, and nearly 50% had a dmft score <3. ECOHIS-4D demonstrated a superior ability to differentiate between dmft severity groups and respond to changes in dmft scores. A significant weak correlation was observed between dmft and ECOHIS-4D (-0.26, 95%, CI -0.36 to -0.15) compared to a non-significant very poor correlation between dmft and CHU-9D (0.01, 95% CI -0.12 to 0.10). The utility scores of the two instruments had relatively good agreement towards good health and weak agreement towards poor health.

CONCLUSIONS

ECOHIS-4D, the oral health-specific instrument, is more sensitive in assessing children's oral health-related quality of life than the generic CHU-9D. Thus, ECOHIS-4D is more appropriate for utility estimates in economic evaluations of oral health-related interventions and resource allocation decision-making.

Developing an Australian utility value set for the Early Childhood Oral Health Impact Scale-4D (ECOHIS-4D) using a discrete choice experiment

PURPOSE

Preference-based quality of life measures (PBMs) are used to generate quality-adjusted life years (QALYs) in economic evaluations. A PBM consists of (1) a health state classification system and (2) a utility value set that allows the instrument responses to be converted to QALYs. A new, oral health-specific classification system, the Early Childhood Oral Health Impact Scale-4D (ECOHIS-4D) has recently been developed. The aim of this study was to generate an Australian utility value set for the ECOHIS-4D.

METHODS

A discrete choice experiment with duration (DCETTO) was used as the preference elicitation technique. An online survey was administered to a representative sample of Australian adults over 18 years. Respondents were given 14 choice tasks (10 tasks from the DCE design of 50 choice sets blocked into five blocks, 2 practice tasks, a repeated and a dominant task). Data were analyzed using the conditional logit model.

RESULTS

A total of 1201 respondents from the Australian general population completed the survey. Of them, 69% (n = 829) perceived their oral health status to be good, very good, or excellent. The estimated coefficients from the conditional logit models were in the expected directions and were statistically significant (p < 0.001). The utility values for health states defined by the ECOHIS-4D ranged from 0.0376 to 1.0000.

CONCLUSIONS

This newly developed utility value set will enable the calculation of utility values for economic evaluations of interventions related to oral diseases such as dental caries among young children. This will facilitate more effective resource allocation for oral health services.

Methodological challenges surrounding QALY estimation for paediatric economic evaluation

Cost-utility analysis remains the preferred form of economic evaluation for health technology assessment, pricing and reimbursement authorities in several countries. The results of cost-utility analyses are commonly expressed in terms of incremental cost per quality-adjusted life year (QALY) gained where the QALY combines length of life and health-related quality of life in a single metric. This commentary provides an overview of key methodological challenges surrounding QALY estimation for paediatric economic evaluation. These challenges include issues surrounding the relevant attributes to incorporate into measurement instruments, appropriate respondents for the measurement and valuation tasks, perspectives adopted when completing valuation tasks, potential sources of bias in the description and valuation processes, and the paucity of psychometric evidence for existing measures. In addition, the commentary considers methodological challenges raised by research aimed at assessing whether a QALY gain by a child should be valued equally to a QALY gain by an adult.