Economic evaluation of fluoride varnish application of daily supervision versus daily supervision and additional six-monthly intervals in Scotland (Protecting Teeth @ 3): a randomised controlled trial

Abstract Background Economic evaluations of public health interventions aid decision makers in efficient resource allocation. Our aim was to do an economic evaluation of a subintake of the Protecting Teeth @ 3 Study (PT@3), a Scottish, 2 year, parallel group, randomised controlled trial, which explored the additional preventive value of fluoride varnish application at six-monthly intervals in nursery settings over and above daily supervised toothbrushing in nursery settings (treatment as usual). Methods From Nov 21, 2012 to Aug 31, 2017, eligible children were randomly assigned to receive either fluoride varnish plus treatment as usual (fluoride varnish group) or treatment as usual in a 1:1 ratio. The economic evaluation was a within-trial, cost-utility analysis comparing the fluoride varnish group with the treatment as usual group. Cost-utility analysis was done from a National Health Service perspective. Within-trial costs included intervention and health-care resource use costs. Health outcomes were expressed in quality-adjusted life-years (QALYs) accrued over the 2 year period. The Child Health Utility 9 Dimensions questionnaire was used to obtain utility scores. Staff travel and labour costs were collected using a staff costs form. Information on other costs was requested from the trial coordinators. National reference costs were used, a discount rate of 1·5% for public health investments was adopted, multiple imputation methods for missing data were employed, sensitivity analyses done, and incremental cost-effectiveness ratios calculated. Ethical approval was from the West of Scotland Research Ethics Service. This trial is registered with EudraCT, 2012-002287-26. Findings The data for 534 participants from the 2014–15 intake were used in the analyses. Of these, 265 were assigned to fluoride varnish and assigned to 269 treatment as usual. The mean difference in costs between the fluoride varnish and treatment as usual group was GBP£36·64 (95% CI –48·51 to 111·47; p=0·64). The mean difference in QALYs was –0·0044 (95% CI –0·0168 to 0·0065; p=0·64). The fluoride varnish intervention had higher costs and resulted in less QALYs than that of the treatment as usual. The probability that the fluoride varnish intervention was cost-effective at the £30 000 threshold was 18·5%. Interpretation Our results indicate that there was no substantial difference in costs and QALYs between the two groups. Applying fluoride varnish in nursery settings in addition to daily supervised nursery toothbrushing seems not to be good value for money. We recommended that the funds could be used better on other more cost-effective oral health interventions. Funding PT@3 was funded by the Scottish Government.