|dc.description.abstract||The first aim of this study was to investigate the availability of quality adjusted life years (QALY), for two oral health related quality of life (OHRQoL) measures, the Child Perceptions Questionnaire for 8-10-year-olds (CPQ8-10) and the Child Perceptions Questionnaire for 11-14-year-olds (CPQ11-14ISF:16), using a general health-related quality of life (HRQoL) measure, the Child Health Utility 9D (CHU-9D), that can produce utility values as a proxy.
The second aim of this study was to investigate whether the CHU-9D can be used as a Quality of Life (QoL) measure for longitudinal oral health research.
Two separate studies were conducted using data from an ongoing Dunedin Randomised Control Trial (RCT), the Proximal Resin Infiltrant New Zealand study (PRINZ). Participants between seven and nine years of age, who attended one of eleven Dunedin schools, and who were registered to receive their dental care with the Bachelor of Oral Health (BOH) programme, were invited to attend. Ethical approval was obtained, as well as written parental consent, and child assent.
Sociodemographic information was collected, including age, sex, deprivation, and ethnicity. Clinical data were collected through comprehensive dental examinations conducted by one of two calibrated dental therapists. Digital posterior bitewing radiographs were taken using standardised bitewing holders. The numbers of decayed, missing and filled surfaces were documented at each dental examination for both primary and permanent dentitions, along with the number of primary and permanent teeth present.
The CHU-9D was administered six-monthly during the participants’ dental recall examinations. The CPQ11-14ISF:16 and CPQ8-10 measures were administered at the initial examination, and at the last dental examination prior to completing the study. Participants with a baseline CPQ measure and corresponding CHU-9D measure with clinical data were included in the first study, which investigated using the CHU-9D as a proxy to produce a QALY for the CPQ measures. Participants with at least one follow-up CHU-9D measure and corresponding clinical data were included in the second study, which investigated whether the CHU-9D could be used as a QoL measure for longitudinal oral health related research. All data were analysed using Stata v13.
82 participants aged between seven and ten were eligible for inclusion in the first study, and 87 in the second study. Because there was a large proportion of participants common to both studies, socio-economic and caries data were similar for each. Both studies had similar numbers of girls and boys, with most being 8 or 9 years of age. More than two-thirds of the children identified as NZ European, with fewer than one in five being NZ Mäori. There were similar proportions of participants residing in areas of low or high deprivation, with slightly more children living in areas of medium deprivation. Caries experience was lower for NZ European participants and those living in areas of low deprivation.
For the OHRQoL measures, both CPQ8-10 and CPQ11-14ISF:16 scores showed a consistent gradient at baseline across ordinal categories of caries experience. By comparison, the CHU-9D had inconsistent utility values by caries experience category, with children in the caries-free group reporting the same QoL as those with the greatest burden of disease. Scatter plots between the CHU-9D and both the CPQ8-10 and CPQ11-14ISF:16 demonstrated a large amount of variance at both baseline and follow-up, with a correlation coefficient of -0.3 at baseline for both the CPQ8-10 and CPQ11-14ISF:16, and -0.5 at follow-up.
For HRQoL at baseline, the CHU-9D did not demonstrate a clear descending gradient in utility score across the ordinal categories of caries experience. There was a slightly more discernible pattern at times 2, 3 and 4, but it was not convincing.
For the first study of 82 Dunedin children between 7 and12 years of age, the CHU-9D showed low concordance with both the CPQ8-10 and CPQ11-14ISF:16. Thus the CHU-9D was unable to be used as a proxy to calculate a QALY in this group of children.
The second study of 87 Dunedin children between 7 and 12 years of age, showed that the CHU-9D was not sensitive to caries experience at baseline, and so the measure is unable to detect or reflect change in caries experience over time.||