DOI: 10.1111/ipd.12177

Can the Child Health Utility 9D measure be useful in oral health research? LYNDIE A. FOSTER PAGE1, DEANNA M. BECKETT1, CLAIRE M. CAMERON2 & W. MURRAY THOMSON1 1

Department of Oral Sciences, Sir John Walsh Research Institute, School of Dentistry, University of Otago, Dunedin, New Zealand, and 2Department of Preventive and Social Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand

International Journal of Paediatric Dentistry 2015; 25: 349–357 Background. Cost-utility analysis using the qual-

ity-adjusted life years (QALY) as an outcome measure to inform healthcare resource allocation is becoming more common. The Child Health Utility 9D (CHU9D) enables the calculation of utility values in children. Children were involved throughout its development to ensure it is child centred. Aim. To determine whether the CHU9D is responsive to the changing components of the dmfs+DMFS index score in children receiving dental care over a 1-year period. Design. The study sample comprised children aged 6 to 9 years old who were enrolled in a splitmouth, placebo-controlled randomised controlled trial. All children had a comprehensive clinical examination including radiographs and health-

Introduction

The Child Health Utility 9D (CHU9D) is a health-related quality of life (HRQoL) measure that has been developed for use in 7- to 11-year-old children to identify health dimensions that are important to them. Children were involved throughout its development to ensure that it is child centred1. Parents or caregivers have commonly been used to report on HRQoL for children, and the CHU9D is unique in that children report on their own HRQoL. It features items which are common to other child oral health self-report measures, such as ‘pain’, ‘problems sleeping’, and ‘usual activities’. These measures can offer advantages over others because of their Correspondence to: Lyndie A. Foster Page, Sir John Walsh Research Institute, School of Dentistry, PO Box 647, Dunedin, New Zealand. E-mail: [email protected]

related quality of life (HRQoL) was measured using the CHU9D at baseline and 1 year. Descriptive statistics was followed by bivariate analyses before effect sizes were calculated. A negative binomial model was fitted to assess whether the utility score predicted the components of decayed and filled teeth (combined primary and permanent teeth). Results. Eighty (92%) children completed the CHU9D at baseline and follow-up. They presented with a mean baseline d3mfs+D3MFS of 6.7 (SD = 7.1), which rose to 7.3 (SD = 7.0) at follow-up. The mean CHU9D score improved from 0.88 to 0.90 from baseline to follow-up. No statistically significant relationships were found between caries status and the CHU9D score. Conclusion. The CHU9D was found to be unresponsive to the changing components of dental caries experience.

broad applicability, whereby they allow comparisons among people with different conditions, and they yield index scores that can be applied in economic evaluations of health. In the last decade, there has been considerable attention paid to the performance of HRQoL measures in oral health studies, particularly to investigate the relative costs and benefits of different interventions2. Cost-utility analysis using the quality-adjusted life year (QALY) as an outcome measure to inform healthcare resource allocation is becoming more common. It is particularly useful because it allows comparisons both within and across disparate clinical areas of interest3. In adults, the EuroQol (EQ-5D) and the Assessment of Quality of Life (AQoL) instruments have been found to have both discriminative and convergent validity in respect of oral health, supporting their use in oral health studies4. In a cross-sectional study of New Zealand children attending for routine

© 2015 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

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dental examinations, the CHU9D showed promise, as indicated by its excellent concurrent validity and adequate construct validity5. Although the CHU9D showed a difference in utility score in the hypothesised direction, the difference was not statistically significant, suggesting that the CHU9D was not sensitive enough in that sample of children. The authors concluded that the CHU9D might not be able to detect the impact of dental caries when the overall caries experience and associated impact is low5. The substantial decline in caries experience in children in countries with high social and economic development is well documented6–9. For example, recent national survey estimates from New Zealand indicate that 51.0% of 5to 11-year-old children (most of whom are in the mixed dentition) were free of obvious caries in their primary teeth, with the majority (77.5%) having permanent teeth free of obvious caries10. Although improvements have been seen, a large proportion of the total dentistry budget is still spent on treating dental caries. More recently, there has been a shift from the surgical treatment of dental caries to managing the disease11. Such approaches include more non-invasive (fluoride varnish applications, toothbrush programmes) and micro-invasive (proximal sealing and infiltrating) procedures. There have also been systematic investigations of other approaches to managing severe caries, such as comparing stainless steel crown placement (with no caries removal) with traditional restorative techniques12. In economic evaluations, the costs of an intervention are compared to its benefits. These can be used to determine the efficiency of a new intervention relative to one or more established alternatives. An oral health costeffectiveness study has been conducted alongside a clinical trial to evaluate the effects of caries-preventive strategies among 6-year-olds in the Netherlands and found that non-operative caries treatment and prevention programme regimen was more effective and more costly than regular dental care13. The evaluated cost-effectiveness as additional average cost per prevented DMFS provides

important economic evaluation of the benefits associated with those strategies; however, the findings can only be applied to the dental setting, as they did not use any instruments to derive QALYs (no cost-utility analysis was conducted). Utility data would allow oral health practitioners to advocate using QALYbased information for allocating scarce health system resources to needed dental care. An example of this would be the ability to show that providing dental care for a child under general anaesthetic might provide greater health gains than providing a different child health-related procedure elsewhere. It has been advocated that HRQoL instruments such as the CHU9D should be routinely included in randomised controlled trials in order to obtain QALY information to supplement the clinical data14. For this to occur in child oral health clinical trials, we need to investigate whether the CHU9D is sensitive in children with caries undergoing treatment, and, if any change in CHU9D is observed, what aspects of caries treatment are likely to have been responsible. For example, it could be that the main contribution to positive change in the CHU9D is the treatment-associated conversion of decayed surfaces to filled ones, or it could be a consequence of the extraction of painful teeth (the conversion of decayed surfaces to missing ones) during the dental treatment. This study aimed to determine whether the CHU9D is responsive to the changing components of the dmfs+DMFS index score in children receiving dental care over a 1-year period. A second aim was to determine the minimum number of participants required to produce a detectable and important difference in the CHU9D in a clinical trial designed to detect differences in clinical interventions. Method

Ethical approval for the study was obtained from the Upper South A Regional Ethics Committee, New Zealand (URA/11/08/037). The study sample comprised children aged 6 to 9 years old who were enrolled in a splitmouth, placebo-controlled randomised control trial of the caries-preventive efficacy of

© 2015 BSPD, IAPD and John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Responsiveness of the CHU9D

resin infiltration in Otago New Zealand. Children – each with 2 proximal lesions confined to the inner half of enamel or ≤0.5 mm into dentine – were included. Lesions were randomly allocated to test (infiltration: ICONpre-product; Dental Material Gesellschaft and fluoride varnish) or control (fluoride varnish). Participants were clinically examined after 6 and 12 months, and the primary outcome measure was radiographic lesion progression. Here, we describe the self-reported healthrelated quality of life data collected at baseline and 1 year. The sample size calculation for this clinical trial was based on parameters from a previous proximal caries study15: paired observations (split-mouth design); a = 5%; 1- ß = 80%; and the clinically relevant effect not to be missed 20%. Using the McNemar test for differences in proportions for the paired-sample design, the estimated sample size was 68 participants. Information was gathered on each child’s sex, age, and ethnicity. An area-based deprivation measure16 was used to allocate each participant to a deprivation score, based on the residential address. Areas with scores 1 to 3 were classified as ‘low deprivation’; those with scores 8 to 10 were classified as ‘high deprivation’. All children had a comprehensive clinical examination by one of two dental therapists, with one therapist conducting the majority (95%) of baseline examinations and all of the follow-up examinations. Visual examination was conducted under light using a flat dental mirror, explorer, and triplex air syringe. Teeth were washed and dried, and cotton roll isolation used to maintain a dry field. Residual interproximal plaque was removed with an explorer or dental floss. An explorer was used without pressure to evaluate the integrity of the tooth surface. Bitewing radiographs using a standardised bitewing holder at baseline were taken and read by one of two dental therapists, with one therapist conducting the majority of baseline (95%) and all of the follow-up (12 months) radiographs and readings, as with the clinical examinations. To be included in the study, children were required to have at least 2 radiographically observed proximal carious lesions in contralateral

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posterior primary molars. Baseline charting recorded for each child included the recording of surface-level caries status (at the d3 level) in both the primary and permanent dentition, enabling determination of the number of decayed, missing, and filled surfaces in each dentition (dmfs+DMFS). These were summed for both dentitions to give an overall decayed, filled, and missing surfaces score for each child. The total number of primary and permanent teeth present at examination was recorded to enable calculation of the overall percentage of primary and permanent surfaces affected. Digital bitewing radiographs taken at the time of the clinical examination were read later, and the caries status of the participant was adjusted by incorporating the caries diagnosis for the mesial, occlusal, and distal surfaces of the posterior teeth in the primary and permanent dentition. Radiographs were scored following the modified radiographic scoring system: 0, no radiolucency; 1, outer half of enamel; 2, inner half of enamel; 3,

Can the Child Health Utility 9D measure be useful in oral health research?

Cost-utility analysis using the quality-adjusted life years (QALY) as an outcome measure to inform healthcare resource allocation is becoming more com...
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