Cost-benefit analysis in dentistry - combining HERU's expertise in valuation and economic evaluation
2019-10-23

We know surprisingly little about how effective or cost-effective dental interventions are. For example, in the UK each year people have over 15 million scale and polish treatments on the NHS. Yet, there is no strong evidence that scale and polish prevents poor dental health or that scale and polish is good value for money. This means that NHS resources may be wasted. In HERU, we have worked with researchers from across the UK to increase the evidence in this area. We are carrying out several economic evaluations of dental treatments and services. These studies are researching:

It is difficult to assess the value for money of dental care. This blog post discusses why it is difficult and briefly describes our research in this area.

tooth

How should we value the outcomes of dental care?


When we assess if dental care is good value for money to the NHS, we need to know how much it costs and the value of the treatment outcomes. It is difficult to value the outcomes of dental care.

The recommended, and most popular, outcome measure in economic evaluation is the Quality Adjusted Life Year (QALY). The QALY combines the quantity of life (life years) gained from care and change in quality of life due to care. Quality of life is often measured using the EQ-5D. In England, the National Institute for Health and Care Excellence (NICE) considers the additional cost for every QALY gained to help them to decide which treatments the NHS should provide.

Some dental care such as scale and polish or fillings for tooth decay do not change people’s life expectancy or cause large, long-term changes in people’s general health. For example, painful tooth decay is usually short-lived and can be treated with a filling.

But, quality of life may not be the only outcome that matters to people when they visit the dental practice. People might also care about how their teeth look and feel. In HERU we use our long-standing expertise in valuing patient preferences (including Discrete Choice Experiments) and economic evaluation (including evaluation of in-use technologies and incorporation of broader measures of value into economic evaluations) to carry out cost-benefit analyses which include all outcomes that matter to people.

 

Case study: Scale and polish and personal oral hygiene advice: Improving the Quality of Dentistry (IQuaD) study.


We used a discrete choice experiment (DCE) survey to ask over 600 people about their preferences for scale and polish and oral hygiene advice. We asked people to make ten choices between two different dental care packages or no dental care package. The dental packages were described using five attributes:

  1. The frequency of scale and polish offered (6-monthly, 12-monthly or none)

  2. The type of dental advice (personalised or normal)

  3. How often they have bleeding gums when brushing their teeth

  4. How clean their teeth look and feel

  5. Cost of the package

 

People value scale and polish


The results showed that people highly valued scale and polish. People were willing to pay £98 per year to have a scale and polish from the dentist. But people were only willing to pay £25 per year to have personalised oral hygiene advice from the dentist.

People were willing to pay more to avoid having teeth that look and feel very unclean (£85 per year) than they were to avoid having gums that bleed very often (£54). People were willing to pay for dental care over and above the health and aesthetic outcomes they receive. However, our data cannot tell us why people value dental care itself so highly.

 

Bringing together costs and benefits


The DCE was part of a larger study (IQuaD). 1877 adults, with healthy gums, who regularly attended NHS dental practices across Scotland and north-east England were involved. Trial participants were randomly offered:

  • a scale and polish every 6 months.

  • a scale and polish every 12 months.

  • no scale and polish at all.

Trial participants also received normal or personalised oral hygiene advice, depending on which dental practice they attended.

randomisation figure

 

Trial participants were followed for 3 years. We asked them about their dental health, use of NHS care, and the cost (NHS charges, time and travel) to them when they visited their dental practice.

The group that were not offered a scale and polish had the lowest NHS costs. On average, these participants saved £64 over 3 years. These savings include the cost of their time, travel, and NHS charges.

We found no evidence that scale and polish or personalised oral hygiene advice prevented bleeding gums or improved people’s dental health. If we measure value for money in terms of dental health (the health perspective) then no scale and polish is the best and cheapest option.

Our DCE showed that people value having a scale and polish and are willing to pay for this. The value of a scale and polish to people is larger than the cost to the NHS of providing scale and polish. If we measure value for money in terms of all the things that people care about (health and non-health related) (the societal perspective), then the best option is scale and polish every 6 months.

So, the best option depends on what point of view is taken and what we think the NHS should aim to do. This may make it harder to decide on how best to spend NHS money, but it is important that decision makers have all the available evidence, and this includes both the health and societal perspectives.

 

The full report of the iQuaD trial is available online via the Health Technology Assessment journal:

Ramsay, C.R., Clarkson, J.E., Duncan, A., Lamont, T.J., Heasman, P.A., Boyers, D., Goulao, B., Bonetti, D., Bruce, R., Gouick, J., Heasman, L., Lovelock-Hempleman, L.A., Macpherson, L.E., McCracken, G.I., McDonald, A.M., McLaren-Neil, F., Mitchell, F.E., Norrie, J.D., Pol, M. van der, Sim, K., Steele, J.G., Sharp, A., Watt, G., Worthington, H.V. and Young, L. (2018) 'Improving the Quality of Dentistry (IQuaD): a cluster factorial randomised controlled trial comparing the effectiveness and cost-benefit of oral hygiene advice and/or periodontal instrumentation with routine care for the prevention and management of periodontal disease in dentate adults attending dental primary care'Health Technology Assessment, 22(38). DOI: 10.3310/hta22380.

 

The IquaD study was funded by the National Institute for Health Research Health Technology Assessment Programme (Project Number 09/01/45). The views and opinions expressed herein are those of the authors and do not necessarily reflect those of the HTA programme, NIHR, NHS, or the Department of Health. The Health Services and Health Economics Research Units are funded by the Chief Scientist Office of the Scottish Government Health & Social Care Directorates.

 

Thanks to Dwayne Boyers of HERU for his work on producing this blog post, and to Verity Watson and Marjon van der Pol for contributing.

Dwayne Boyers

 

HERU is supported by the Chief Scientist Office (CSO) of the Scottish Government Health and Social Care Directorates (SGHSC). The views expressed here are those of the Unit and not necessarily those of the CSO.

 

Published by HERU, University of Aberdeen

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