A critique of recent economic evaluations of community water fluoridation

Cost-effectiveness analysis design for interventions to prevent children's oral disease

Introduction

In 2015, the National Institute of Dental and Craniofacial Research (NIDCR) launched the Multidisciplinary Collaborative Research Consortium to Reduce Oral Health Disparities in Children, supporting four randomized trials testing strategies to improve preventive care. A Coordinating Center provides scientific expertise, data acquisition and quality assurance services, safety monitoring, and final analysis-ready datasets. This paper describes the trials' economic analysis strategies, placing these strategies within the broader context of contemporary economic analysis methods.

Methods

The Coordinating Center established a Cost Collaborative Working Group to share information from the four trials about the components of their economic analyses. Study teams indicated data sources for their economic analysis using a set of structured tables. The Group meets regularly to share progress, discuss challenges, and coordinate analytic approaches.

Results

All four trials will calculate incremental cost-effectiveness ratios; two will also conduct cost-utility analyses using proxy diseases to estimate health state utilities. Each trial will consider at least two perspectives. Key process measures include dental services provided to child participants. The non-preference-weighted Early Childhood Oral Health Impact Scale (ECOHIS) will measure oral health-related quality of life. All trials are measuring training, implementation, personnel and supervision, service, supplies, and equipment costs.

Conclusions

Consistent with best practices, all four trials have integrated economic analysis during their planning stages. This effort is critical since poor quality or absence of essential data can limit retrospective analysis. Integrating economic analysis into oral health preventive intervention research can provide guidance to clinicians and practices, payers, and policymakers.

A cost-effectiveness analysis of community water fluoridation for schoolchildren

BACKGROUND

Community water fluoridation (CWF), the controlled addition of fluoride to the water supply for the prevention of dental caries (tooth decay), is considered a safe and effective public health intervention. The Republic of Ireland (Ireland) is the only country in Europe with a legislative mandate for the fluoridation of the public water supply, a key component of its oral health policy. However, more recently, there has been an increase in public concern around the relevance of the intervention given the current environment of multiple fluoride sources and a reported increase in the prevalence of enamel fluorosis. The aim of this economic analysis is to provide evidence to inform policy decisions on whether the continued public investment in community water fluoridation remains justified under these altered circumstances.

METHODS

Following traditional methods of economic evaluation and using epidemiological data from a representative sample of 5-, 8-, and 12-year-old schoolchildren, this cost-effectiveness analysis, conducted from the health-payer perspective, compared the incremental costs and consequences associated with the CWF intervention to no intervention for schoolchildren living in Ireland in 2017. A probabilistic model was developed to simulate the potential lifetime treatment savings associated with the schoolchildren's exposure to the intervention for one year.

RESULTS

In 2017, approximately 71% of people living in Ireland had access to a publicly provided fluoridated water supply at an average per capita cost to the state of €2.15. The total cost of CWF provision to 5-, 8-, and 12-year-old schoolchildren (n = 148,910) was estimated at €320,664, and the incremental cost per decayed, missing, or filled tooth (d3vcmft/D3vcMFT) prevented was calculated at €14.09. The potential annual lifetime treatment savings associated with caries prevented for this cohort was estimated at €2.95 million. When the potential treatment savings were included in the analysis, the incremental cost per d3vcmft/D3vcMFT prevented was -€115.67, representing a cost-saving to the health-payer and a positive return on investment. The results of the analysis were robust to both deterministic and probability sensitivity analyses.

CONCLUSION

Despite current access to numerous fluoride sources and a reported increase in the prevalence of enamel fluorosis, CWF remains a cost-effective public health intervention for Irish schoolchildren.

Association Between Community Water Fluoridation and Severe Dental Caries Experience in 4-Year-Old New Zealand Children

IMPORTANCE

Robust contemporary epidemiologic evidence for the population-wide efficacy of reticulated community water fluoridation is required.

OBJECTIVE

To evaluate whether community water fluoridation is associated with the national rates of severe caries among 4-year-old children in New Zealand after accounting for key sociodemographic characteristics.

DESIGN, SETTING, AND PARTICIPANTS

This was a near whole population-level, natural, geospatial cross-sectional study of 4-year-old children who had a health and development assessment as part of the nationwide B4 School Check screening program conducted in New Zealand between July 1, 2010, and June 30, 2016. The extracted database included 391 677 children. However, geospatial information was missing for 18 558 children, another 32 939 children were unable to be geospatially matched, 5551 children resided in areas with changing fluoridation status, and 58 786 children had no oral health screen recorded, leaving 275 843 (70.4%) eligible children. Data were released in August 2019; statistical analysis was performed from September 2019 to December 2019.

EXPOSURES

Community water fluoridation status from 2011 through 2016.

MAIN OUTCOMES AND MEASURES

Severe caries experience derived from the "lift the lip" oral health screening. Analyses were adjusted for age, sex, ethnicity, area-level deprivation, and residential location differences. Multilevel mixed-effects logistic regression models were used. Sensitivity analyses based on multiple imputed data were undertaken to measure any differential influence of missing data.

RESULTS

In the eligible sample of 275 843 children, the median age was 4.3 years (interquartile range, 4.1-4.6 years), 141 451 children (51.3%) were boys, and 153 670 children (55.7%) resided within fluoridated areas. Severe caries were identified for 24 226 children (15.8%) in fluoridated and 17 135 children (14.0%) in unfluoridated areas, yielding an unadjusted odds ratio of 0.93 (95% CI, 0.90-0.95). However, in the adjusted analyses, children residing in areas without fluoridation had higher odds of severe caries compared with those within fluoridated areas (odds ratio, 1.21; 95% CI, 1.17-1.24). The population attributional fraction associated with unfluoridated community water was 5.6% (95% CI, 4.7%-6.6%) in a complete case analysis.

CONCLUSIONS AND RELEVANCE

This study finds that community water fluoridation continues to be associated with reduced prevalence of severe caries in the primary dentition of New Zealand's 4-year-old children.

Economic evaluations in water-fluoridation: a scoping review

Background

Community water fluoridation (CWF) is considered one of the 10 greatest public health achievements of the twentieth century and has been a cornerstone strategies for the prevention and control of dental caries in many countries. However, for decision-makers the effectiveness and safety of any given intervention is not always sufficient to decide on the best option. Economic evaluations (EE) provide key information that managers weigh, alongside other evidence. This study reviews the relevant literature on EE in CWF.

Methods

A systematic database search up to August 2019 was carried out using MEDLINE, EMBASE, Cochrane Library, LILACS, Paediatric Economic Database Evaluation and National Health Service Economic Evaluation Database. The review included full economic evaluations on CWF programs, written in English, Spanish or Portuguese. The selection process and data extraction were carried out by two researchers independently. A qualitative synthesis of the results was performed.

Results

Of 498 identified articles, 24 studies met the inclusion criteria; 11 corresponded to cost-benefit analysis; nine were cost-effectiveness analyses; and four cost-utility studies. Two cost-utility studies used Disability-Adjusted Life Years,, one used Quality-Adjusted Tooth Years, and another Quality-Adjusted Life Years. EEs were conducted in eight countries. All studies concluded that water fluoridation was a cost-effective strategy when it was compared with non-fluoridated communities, independently of the perspective, time horizon or discount rate applied. Four studies adopted a lifetime time horizon. The outcome measures included caries averted (n = 14) and savings cost of dental treatment (n = 4). Most of the studies reported a caries reduction effects between 25 and 40%.

Conclusion

Findings indicated that CWF represents an appropriate use of communities’ resources, using a range of economic evaluation methods and in different locations. These findings provide evidence to decision-makers which they could use as an aid to deciding on resource allocation.

Potential Co-exposure to Arsenic and Fluoride and Biomonitoring Equivalents for Mexican Children

BACKGROUND

Mexico is included in the list of countries with concurrent arsenic and fluoride contamination in drinking water. Most of the studies have been carried out in the adult population and very few in the child population. Urinary arsenic and urinary fluoride levels have been accepted as good biomarkers of exposure dose. The Biomonitoring Equivalents (BE) values are useful tools for health assessment using human biomonitoring data in relation to the exposure guidance values, but BE information for children is limited.

METHODS

We conducted a systematic review of the reported levels of arsenic and fluoride in drinking water, urinary quantification of speciated arsenic (inorganic arsenic and its methylated metabolites), and urinary fluoride levels in child populations. For BE values, urinary arsenic and fluoride concentrations reported in Mexican child populations were revised discussing the influence of factors such as diet, use of dental products, sex, and metabolism.

RESULTS

Approximately 0.5 and 6 million Mexican children up to 14 years of age drink water with arsenic levels over 10 μg/L and fluoride over 1.5 mg/L, respectively. Moreover, 40% of localities with arsenic levels higher than 10 μg/L also present concurrent fluoride exposure higher than 1.5 mgF/L. BE values based in urinary arsenic of 15 μg/L and urinary fluoride of 1.2 mg/L for the environmentally exposed child population are suggested.

CONCLUSIONS

An actual risk map of Mexican children exposed to high levels of arsenic, fluoride, and both arsenic and fluoride in drinking water was generated. Mexican normativity for maximum contaminant level for arsenic and fluoride in drinking water should be adjusted and enforced to preserve health. BE should be used in child populations to investigate exposure.

Costs And Savings Associated With Community Water Fluoridation In The United States

The most comprehensive study of US community water fluoridation program benefits and costs was published in 2001. This study provides updated estimates using an economic model that includes recent data on program costs, dental caries increments, and dental treatments. In 2013 more than 211 million people had access to fluoridated water through community water systems serving 1,000 or more people. Savings associated with dental caries averted in 2013 as a result of fluoridation were estimated to be $32.19 per capita for this population. Based on 2013 estimated costs ($324 million), net savings (savings minus costs) from fluoridation systems were estimated to be $6,469 million and the estimated return on investment, 20.0. While communities should assess their specific costs for continuing or implementing a fluoridation program, these updated findings indicate that program savings are likely to exceed costs.

The effect of social geographic factors on the untreated tooth decay among head start children

Background

Disparities among untreated dental caries exist for children from low-income families in the United States. Understanding of the mechanism of the disparities is required to reduce it and social geographic factors are one of the important influences. Although the effect of fluoridated water has been well reported, studies of other sociogeograpic factors, such as the density of available dentists, are still very limited. The objective of this study is to explore the effect of sociogeographic factors on the number of primary teeth with untreated dental caries among children from low-income families who are enrolled in Head Start programs throughout Northeast Ohio of the United States.

Material and Methods

This was a cross-sectional chart review study. Three hundred-eighty-eight charts were reviewed, and the number of primary teeth with untreated dental caries (dt) and the children’s addresses were retrieved. The sociogeographic variables, including fluoridated water availability and the density of available dentists who accept a government-supported insurance (Medicaid dentists), were collected.

Results

The mean (standard deviation) of children’s age was 3.51 (1.14) years with a range of 7 months to 5 years. A negative binomial regression model analysis, which used dt as a dependent variable and children’s characteristic factors (i.e. age, gender, insurance type, and total number of primary teeth) and sociogeographic factors (i.e. Population, total number of Medicaid dentists, density of Medicaid dentist, and Fluoride water availability) of cities, as independent variables, demonstrated that only the density of Medicaid dentist in the sociogeographic factors indicated a significant effect (Estimated ß-Coefficients (Standard Errors)=-0.003 (0.002), p=0.030).

Conclusions

This study demonstrated a significant negative association between the density of available dentists and untreated dental caries among children from low-income families in Head Start programs in Northeast Ohio. Increasing available dentists may be a strategy to reduce the number of early childhood caries.

Key words:Child, poverty, dental caries, Health Services Accessibility.

Economic Evaluation of Community Water Fluoridation: A Community Guide Systematic Review

CONTEXT

A recently updated Community Guide systematic review of the effectiveness of community water fluoridation once again found evidence that it reduces dental caries. Although community water fluoridation was found to save money in a 2002 Community Guide systematic review, the conclusion was based on studies conducted before 1995. Given the update to the effectiveness review, re-examination of the benefit and cost of community water fluoridation is necessary.

EVIDENCE ACQUISITION

Using methods developed for Community Guide economic reviews, 564 studies were identified within a search period from January 1995 to November 2013. Ten studies were included in the current review, with four covering community fluoridation benefits only and another six providing both cost and benefit information. Additionally, two of the six studies analyzed the cost effectiveness of community water fluoridation. All currencies were converted to 2013 dollars.

EVIDENCE SYNTHESIS

The analysis was conducted in 2014. The benefit-only studies used regression analysis, showing that different measures of dental costs were always lower in communities with water fluoridation. For the six cost-benefit studies, per capita annual intervention cost ranged from $0.11 to $4.92 for communities with at least 1,000 population, and per capita annual benefit ranged from $5.49 to $93.19. Benefit-cost ratios ranged from 1.12:1 to 135:1, and these ratios were positively associated with community population size.

CONCLUSIONS

Recent evidence continues to indicate that the economic benefit of community water fluoridation exceeds the intervention cost. Further, the benefit-cost ratio increases with the community population size.