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The effect of different methods of remuneration on the behaviour of primary care dentists

  1. Paul Brocklehurst1,*,
  2. Juliet Price2,
  3. Anne-Marie Glenny3,
  4. Martin Tickle1,
  5. Stephen Birch4,
  6. Elizabeth Mertz5,
  7. Jostein Grytten6

Editorial Group: Cochrane Effective Practice and Organisation of Care Group

Published Online: 6 NOV 2013

Assessed as up-to-date: 25 AUG 2013

DOI: 10.1002/14651858.CD009853.pub2


How to Cite

Brocklehurst P, Price J, Glenny AM, Tickle M, Birch S, Mertz E, Grytten J. The effect of different methods of remuneration on the behaviour of primary care dentists. Cochrane Database of Systematic Reviews 2013, Issue 11. Art. No.: CD009853. DOI: 10.1002/14651858.CD009853.pub2.

Author Information

  1. 1

    School of Dentistry, The University of Manchester, Manchester, UK

  2. 2

    The University of Manchester, School of Dentistry, Manchester, UK

  3. 3

    School of Dentistry, The University of Manchester, Cochrane Oral Health Group, Manchester, UK

  4. 4

    Faculty of Health Sciences, McMaster University, Centre for Health Economics and Policy Analysis, Department of Clinical Epidemiology and Biostatistics, Hamilton, Ontario, Canada

  5. 5

    San Francisco School of Dentistry, University of California, Preventative and Restorative Dental Sciences, Suite 410, San Francisco, USA

  6. 6

    University of Oslo, Department of Community Dentistry, Oslo, Norway

*Paul Brocklehurst, School of Dentistry, The University of Manchester, Coupland III Building, Oxford Road, Manchester, M13 9PL, UK. paul.brocklehurst@manchester.ac.uk. paul.r.brocklehurst@btopenworld.com.

Publication History

  1. Publication Status: New
  2. Published Online: 6 NOV 2013

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Characteristics of included studies [ordered by study ID]
Clarkson 2008

MethodsStudy type: Cluster-randomised control trial (with 2 x 2 factorial design)

Duration of study: 18 months: six-month fee intervention period from September 2003 to February 2004 followed by a 12-month follow-up period to allow for the recording of any continuing effects of the interventions on dentists’ decisions to place fissure sealants

Setting: Scotland, in areas representing the four most deprived categories (out of seven) in the Scottish post code based system defining deprivation


ParticipantsUnit of randomisation: Dentists

Unit of assessment/analysis: Patient-level outcomes were measured, but the results were presented at dentist-level i.e. the mean percentage of 12- to 14-year-olds receiving fissure sealants for second permanent molars per dentist (weighted by number of children seen)

Method of recruitment:

  • Dentists: Dentists working in deprived areas were recruited using strategies recommended in recent reviews (Foy 2003)
  • Patients: All 12- to 14-year-olds seen by study dentists during the first six months of the study (during which a fee could be claimed by the dentists in the fee-for-service arm) were identified through National Health Service records. A random sample of 25 per dentist was chosen to be assessed (although not all of these children were included in the analysis because some dentists were lost to follow-up, some children's patient records went missing and some children were found not to have erupted second permanent molars)


Inclusion criteria:

  • Dentists:
    • Treating at least four 11- to 13-year-olds per month on average during 2002
    • Working in a deprived area (i.e. in categories 4 to 7 of the 7-category Scottish deprivation categories [DEPCAT] classification)
    • A maximum of one dentist per dental practice (chosen at random) was included


  • Patients:
    • 12- to 14-year-olds
    • Children who visited a study dentist during the first six months of the study (during which a fee could be claimed by the dentists in the fee-for-service arm)


Exclusion criteria:

  • Dentists:
    • Orthodontist
    • Moved/moving
    • Retired/retiring
    • Maternity leave
    • Sick leave
    • Salaried
  • Patients:
    • Children who were found not to have erupted second permanent molars were excluded from the analysis


External validity: The participating dentists may have had different characteristics to the non-participating dentists. Out of the 284 dentists who were eligible to take part, 131 (46%) refused or did not respond (and a further four were not randomised due to being late recruits etc). In choosing to take part, the dentists would have the possibility (depending on which arm they were randomised to) of claiming fee-for-service remuneration on top of their normal capitation remuneration, therefore those that chose not to take part may be less motivated to claim the small sums associated with the fee-for-service remuneration, at least in the context of the study (the fees were to be claimed from the research team rather than via the routine National Health Service channel). In addition, all the dentists were working in deprived areas, which would have different levels of need compared to Scotland as a whole


InterventionsInterventions:

  • Fee-for-service remuneration: GBP 6.80 for each second permanent molar fissure sealed during a six-month period - the level of the fee was set so that it was consistent with the fee level payable through the normal National Health Service system for a restorative fissure sealant application (which may involve removal of enamel caries prior to sealant placement without the insertion of filling composite) and for preventive sealing of third permanent molars (the fee did not affect National Health Service capitation payments which were GBP 2.76 per month to age 12 and GBP 4.01 thereafter)
  • Education regarding evidence-based practice (1-day workshop in four regions run by experts from The Cochrane Oral Health Group, The Centre for Evidence-based Dentistry and The Dental Health Service Research Unit)
  • Both fee-for-service and education


Control: no specific intervention

Applicability:

  • The average age at baseline was from 13.20 years in the education arm to 13.26 years in the both fee-for-service and education arm, and the data on fissure sealant placement was collected up to 18 months after this baseline, so some of the children may have already started to experience decay if their second permanent molars erupted at around 12 years old. Attempting to place fissure sealants soon after the eruption of second permanent molars is considered preferable to waiting a fairly long time after eruption, so the percentage of children with fissure sealants at the end of the study may have been attenuated (this could apply across all of the study arms). Records of any caries already present or any restorations placed would be useful as this could impact on the proportion of fissure sealants placed i.e. dentists in the study may have placed restorations instead of sealants. The authors noted that only two-thirds of eligible dentists claimed a fee, perhaps due to the fact that the child already had caries in their second permanent molars
  • The fee-for-service remuneration did not affect National Health Service capitation payments which were GBP 2.76 per month to age 12 and GBP 4.01 thereafter. The impact of the fee-for-service remuneration was therefore over and above the impact from capitation
  • The authors suggested that the dentists may have found it too inconvenient to claim a fee from the research team, rather than via the routine National Health Service channel, which would normally be the route for claiming fee-for-service remuneration


OutcomesPrimary outcomes:

1) Measures of clinical behaviour of primary care dentists

  • Mean percentage of 12- to 14-year-olds receiving fissure sealants for second permanent molars per dentist (weighted by number of children seen)
  • Risk differences for fee-for-service vs. no fee-for-service and education vs. no education


2) Healthcare costs (including costs of (i) introducing the incentives, (ii) the transaction, (iii) the information systems and (iv) monitoring)

  • Cost-effectiveness of fee-for-service vs. control, education vs. control and both vs. control (reported as the "% change in outcome per £[GBP]")


Adverse outcomes: None stated


Source of fundingChief Scientist Office, Scottish Executive and Scottish Higher Education Funding Council


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low risk“Sampling, randomisation, and analysis were conducted at arm’s length from the study base by the Health Services Research Unit, University of Aberdeen"

The authors state that they carried out randomisation using minimisation, a form of covariate-adaptive randomisation. The process involved four practice-based variables which were obtained pre-randomisation from National Health Service records: the deprivation category for the area of practice, the number of partners in the practice, the throughput of 11- to 13-year-olds and the number of restorative sealant claims in 2002

Allocation concealment (selection bias)Low risk“Sampling, randomisation, and analysis were conducted at arm’s length from the study base by the Health Services Research Unit, University of Aberdeen"

As minimisation was used to randomise the dentists, the dentists would have to have been recruited before the random sequence was generated, which therefore reduces selection bias

Blinding of outcome assessment (detection bias)
Dental health
High risk"A random sample of 25 [patients] per dentist was taken, and data collection forms were sent to each dentist for completion from practice records 12 [months] post-intervention"

 

Blinding was not possible for the dentists, who acted as the outcome assessors after they had received the intervention i.e. data collection forms were sent to each dentist for completion using patient records, which means that the outcome measure depended on the accuracy of the dentists' reports.

The authors stated that given that the sealant placement did not attract a National Health Service fee-for-service payment – and therefore did not generate a National Health Service-held record – it was not possible to corroborate the dentists' sealant placement records. Equally, National Health Service-held records of the dental visit during which the sealant was placed are not reliable as no such record would occur if no other fee-attracting treatment was given during the visit and the child did not require re-registration. The authors stated that other reasons for mismatches are scanning error, transcription error, and delayed submission of claim forms from the practice to the National Health Service body responsible for fee payment. The authors carried out a crosscheck of National Health Service-held records of dental visit dates and practice-reported dates of sealant placement and found matches in 28% (109) of cases.

The authors stated that while it is possible that bias was introduced, this would have applied equally across the intervention arms but this statement is not verifiable. However, the outcome was objective, which lowers the risk of bias even though the outcome was not assessed blindly

Incomplete outcome data (attrition bias)
All outcomes
Unclear riskThere does not appear to be an imbalance of missing data across the fee-for-service and control arms (for example, four dentists in both the fee-for-service and control arms were lost to follow-up), nor an imbalance in the reasons behind missing data in these arms (for example, 7.1% of children were excluded from the fee-for-service arm and 10.4% of children were excluded in the control arm because they did not have erupted second permanent molars). However, the authors do not appear to have conducted statistical analyses to check for possible imbalances, which may have occurred, particularly between the arm where dentists received fee-for-service remuneration and education (six dentists were lost to follow-up in this arm) and the education arm (two dentists were lost to follow-up in this arm).

 

The data were analysed using the intention-to-treat principle. For example, dentists who did not attend the education intervention were mailed the course material and retained in the study on an intention-to-treat basis, thus reducing the use of incomplete outcome data

Selective reporting (reporting bias)Unclear riskNo protocol is cited and it is not stated whether all the prespecified primary outcomes have been reported

Other biasUnclear risk"There was a lower baseline of sealant treatment of second permanent molars in the fee and both arms. No other significant baseline differences in practice or practitioner characteristics were found"

The baseline characteristics and baseline outcomes of the arms were generally balanced (partly due to the fact that minimisation using four dental practice-level variables was carried out at the beginning of the study), thereby reducing the possibility of confounding. No statistically significant differences in baseline characteristics of dental practices/dentists were found between the arms. However, there was a slight imbalance between arms in the patient-level characteristics measured at baseline i.e. there were statistically significant lower percentages of children having at least one sealant treatment of second permanent molars at baseline in the fee-for-service and both fee-for-service and education arms compared to the education and control arms. Even so, the primary analysis (which adjusted for a number of variables including the number of sealants placed in first permanent molars pre-intervention) found a statistically significant difference in favour of the dentists receiving fee-for-service remuneration. However, the secondary analysis (which did not adjust for baseline differences) did not reach statistical significance.

The risk of contamination is not a concern as dentists (rather than patients) were randomised and it is unlikely that communication between dentists in the different arms could have occurred as a maximum of one dentist per dental practice was selected

Coventry 1989

MethodsStudy type: Cluster-randomised control trial (with parallel group design)

Duration of study: 3 years: July 1986 to June 1989

Setting: Six areas in England and two areas in Scotland

  • Capitation arms
    • Northern urban community: Salford
    • Commuter suburb community: Bromley
    • Rural community: Norfolk
    • Scottish community: Grampian
  • Fee-for-service arms
    • Northern urban community: Doncaster
    • Commuter suburb community: Wycombe
    • Rural community: Hereford and Worcester
    • Scottish community: Fife


ParticipantsUnit of randomisation: Health Service administrative areas

Unit of assessment/analysis: Dental practices (the number of dentists varied over time as dentists joined and left dental practices, so the number of dental practices was the stable and primary parameter), dentists, patients, parents and administrators

Method of recruitment:

  • Health Service administrative areas: Areas in England (representing northern urban, commuter suburb and rural communities) and Scotland were considered.
  • Dental practices/dentists: Letters were sent to all dentists on the Family Practitioner Committees (FPC)/Health Boards lists in the selected areas inviting them to join the study, and evening meetings (to which all dentists were invited) were arranged through the appropriate local dental committees. Visits were made to individual dental practices on request of the dentists and all telephone calls or letters from dentists were answered as comprehensively as possible. The number of dentists varied over time as dentists joined and left dental practices, so the number of dental practices was the stable and primary parameter


Inclusion criteria:

  • Health Service administrative areas: Selection was carried out by the study personnel. The four pairs were matched and represented northern urban, commuter suburb, rural and Scottish communities. The pairs were matched initially on the patterns of treatment of the dentists in the areas, defined as the mean number of fillings per course of treatment provided for 10- to 14-year-olds. Other secondary factors were then taken into account, these were dentist-to-population ratios, housing population densities and proportion of the population receiving fluoride in the water supply. Information on the levels of dental health of the child populations was not available so a baseline dental health survey was carried out so that comparisons could be made retrospectively
  • Dental practices/dentists: Negative consent was used, such that all dentists were included in the study except those who specifically refused to take part, or who were deemed ineligible


Exclusion criteria:

  • Health Service administrative areas: Areas where less than 50% of dentists could be included were excluded - one area that was initially considered (Kingston and Richmond) was replaced (by Wycombe) because more than 50% of the dentists refused to take part
  • Dental practices/dentists: Dental practices which did not treat children or that were confined to orthodontics were excluded


External validity: The participating dentists may have had different characteristics to the non-participating dentists. However, out of the 513 dental practices which were eligible to take part, only 159 (31%) refused to take part (negative consent was used, so those that did not reply were included). Also, the dental practices were not choosing whether or not they would be willing to work under a certain remuneration system (as the remuneration system would apply to participating and non-participating dentists in the Health Service administrative areas chosen), only whether or not they would be willing to take part in the study. In addition, the study took place in a range of areas with varying socioeconomic and environmental circumstances


InterventionsIntervention: Capitation remuneration for routine continuing dental care of children (with fee-for-service for initial treatment to make the children dentally fit before entering the capitation system, and for orthodontics, general anaesthetics, domiciliary visits, out-of-hours recalls, oral surgery and items involving laboratory work)

Control: Fee-for-service remuneration for dental care of children


OutcomesPrimary outcomes:

1) Measures of clinical behaviour of primary care dentists

  • For various age groups:
    • Mean number of examinations per child
    • Mean number of teeth filled per child
    • Mean percentage of children having one or more teeth extracted
    • Mean percentage of children receiving active preventive advice
    • Mean percentage of children receiving a scaling
    • Mean percentage of children receiving one or more fissure sealants
    • Mean percentage of children having radiographs
    • Percentage of participating dentists referring patients to the Community Dental Service (and percentage of non-participating dentists)
    • Percentage of dental practices arranging for in-practice emergency treatment of their patients out of routine surgery hours
    • Percentage of dental practices arranging for out of practice emergency treatment of their patients out of routine surgery hours


2) Measures of health service utilisation

  • Mean number of visits per child


3) Measures of patient outcomes

  • For 14- to 15-year-olds:
    • Percentage with caries on at least one tooth
    • Mean decayed/missing/filled permanent teeth (DMFT) (and among regularly attending children)
    • Mean number of decayed teeth (and among regularly attending children)
    • Mean number of missing teeth (and among regularly attending children)
    • Mean number of sound filled teeth
    • Mean number of sound and carious filled teeth
    • Mean number of filled teeth among regularly attending children
    • Percentage with at least one fissure sealant (and among regularly attending children)


  • For 5- to 6-year-olds:
    • Percentage with caries on at least one tooth
    • Mean decayed/missing/filled primary teeth (dmft) (and among regularly attending children)
    • Mean number of decayed teeth (and among regularly attending children)
    • Mean number of missing teeth (and among regularly attending children)
    • Mean number of filled teeth (and among regularly attending children)
    • Percentage with arrested caries on at least one tooth


4) Healthcare costs (including costs of (i) introducing the incentives, (ii) the transaction, (iii) the information systems, and (iv) monitoring)

  • Mean expenditure in GBP per dentist year in participating dental practices during 1988 (percentage change from fee-for service)
  • Mean expenditure in GBP per child in participating dental practices during 1988 (percentage change from fee-for service)


Secondary outcomes:

1) Measures of non-clinical behaviour of primary care dentists such as rates of performing specified non-clinical behaviours (e.g. education and training)

  • Proportion of dentists reporting introducing innovations into their dental practices


2) Measures of unintended consequences including supplier-induced demand (Birch 1988), changes to the types of treatment offered and limitations to access

  • Mean values for temptation expressed by dentists to over-prescribe
  • Mean values for temptation expressed by dentists to under-prescribe
  • Mean values of clinical freedom expressed by dentists
  • Percentage of principals stating that administration had increased greatly/slightly (over the last three years)
  • Percentage of principals stating that bureaucratic intervention had increased/been unchanged/decreased (over the last three years)
  • Percentage of dentists stating views on the accuracy of payment


Source of fundingDepartment of Health


Notes


Risk of bias

BiasAuthors' judgementSupport for judgement

Random sequence generation (selection bias)Low risk"[A] senior officer of the British Dental Association spun a coin to decide which one of each pair of areas should transfer to capitation and which should remain under fee-for-service”

Allocation concealment (selection bias)Low riskRandomisation of the Health Service administrative areas was conducted after the dentists had joined the study, by a senior officer of the British Dental Association, which therefore reduces selection bias

Blinding of outcome assessment (detection bias)
Dental health
High riskThe outcome assessors varied for different outcomes:

  • Dental health: high risk. Unblinded non-participant dentists were trained and calibrated to assess the dental health of a random sample of the children in schools, and the outcomes they measured would have had an element of subjectivity. For example, the authors stated that even though the examiners were taught specific criteria for arrested caries, the diagnoses were idiosyncratic to each examiner (however, the same examiner examined each of the two age groups in each pair of areas, alternating between areas to avoid the possibility of bias due to possible changes in diagnostic standards over time)
  • Patterns of treatment: high risk. The patterns of treatment provided by a sample of the dentists were obtained from the unblinded participant dentists. The outcomes were objective (e.g. the number of children who had radiographs) but they were self reported
  • Patterns of practice and referral: high risk. The unblinded participant dentists’ answers, which would have had an element of subjectivity, were obtained by a questionnaire and unblinded community dental officers in the study areas were asked to record data on the number of referrals and reasons given for referral
  • Dentists' satisfaction and the profession's views: high risk. The unblinded participant dentists’ subjective views were obtained by a questionnaire and the subjective views of representatives of local dental committees in the four capitation areas, representatives of the General Dental Service Committee of the British Dental Association and participant dentists were obtained via structured interviews and meetings
  • Parents' satisfaction: unclear risk. The subjective views of a sample of parents were obtained by a questionnaire. They were not blinded, but the authors stated that many parents were unaware of the remuneration system under which their children were treated
  •  Adminstrators' satisfaction: high risk. The unblinded administrators' subjective views were obtained at meetings at several stages in the study
  • Costs: low risk. The outcomes were objective

Incomplete outcome data (attrition bias)
All outcomes
Unclear risk“During the course of the study, only nine capitation practices chose to withdraw...Two practices withdrew from the control area...”

The number of dental practices which dropped out was very low: 9 (4.9%) in the capitation areas, and 2 (1.2%) in the fee-for-service areas.

The dental health outcomes of 5- to 6-year-olds and 14- to 15-year-olds in each area were collected from a random sample of children from lists provided by the Dental Practice Boards. For 14-to 15 year-olds, 1919 children were examined, 68% of the usable sample (due to parents refusing consent, not replying etc.) For 5- to 6-year-olds, 1938 (69%) were examined. However, the authors do not state the percentage of those who were examined (out of all those who were eligible) in each study arm, nor whether there was an imbalance in the reasons for not being examined.

For the mean expenditure per 0- to 15-year old, all payments made to study dentists for the treatment of 0- to 5-year-olds during 1988 were divided by the estimated numbers of children treated. However, the estimated number is only an approximation as it was impossible to eliminate double-counting, particularly in the fee-for-service system. This means that there is bias that places the capitation arm at a disadvantage

Selective reporting (reporting bias)Unclear riskNo protocol is cited and it is not stated whether all the prespecified primary outcomes have been reported

Other biasHigh riskWithin each of the four replicates in the study there were only two Health Service administrative areas randomised, so the sample sizes were extremely small, which would lead to randomisation providing little protection against confounding. The baseline characteristics and baseline outcomes of the pairs of areas were shown to be unbalanced, which provides evidence of confounding. Although the authors attempted to match the pairs, there were few variables to match them on, which led to the imbalances. For example, in Fife there was an established practice to refer children to the Community Dental Service for preventive treatment (mainly for the placement of fissure sealants) but this procedure was not an important element in any other area (including Grampian, which was matched with Fife). In addition, information on the levels of dental health of the child populations was not available so a baseline dental health survey was carried out so that comparisons could be made retrospectively. The analysis showed that the mean decayed/missing/filled primary teeth (dmft) in 5- to 6-year-olds and 8- to 9-year-olds was significantly greater in Salford compared to Doncaster, and in Bromley compared to Wycombe. This was also true of the mean decayed/missing/filled permanent teeth (DMFT) in 8- to 9-year-olds and 11- to 12-year-olds (though not in 14- to 15-year-olds) in Salford compared to Doncaster. There were no other significant differences in mean decayed/missing/filled primary teeth (dmft) and mean decayed/missing/filled permanent teeth (DMFT) between matched pairs. Where there were significant differences they all favoured the fee-for-service areas i.e. dental health tended to be better in the fee-for-service areas.

Other concerns in cluster-randomised control trials are recruitment bias between clusters involved in different interventions (but the dentists were recruited before randomisation, so the bias should not be present) and loss of clusters (which did not occur)

The risk of contamination is not a concern as areas (rather than dentists or patients) were randomised

Regularly attending children (from the random samples of 5- to 6-year-olds and 14- to 15-year-olds selected from the Dental Practice Boards) were defined as those who had visited the same dentist during the previous year. Using this definition, 70% of the original lists were regular attenders. As the authors noted, it was difficult to define regular attenders in a study which only lasts 3 years. This was made more problematic for the fee-for-service areas in England as the Dental Practice Board kept records for dentists rather than patients and in the capitation areas the patient registrations were built up gradually over a period of months as patients attended for courses of treatment

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Blinkhorn 1996Uncontrolled before-after study (extension of Coventry 1989 study examining patients who had been in the fee-for-service arm and subsequently switched to capitation)

Chalkley 2008Before-after study (on the effect of changing from fee-for-service remuneration to activity-based remuneration) with an inadequate control group

Fiset 2000Uncontrolled before-after study (on the effect of introducing fee-for-service remuneration for providing fluoride varnish)

Holloway 1997Uncontrolled before-after study (extension of Coventry 1989 study examining patients who had been in the fee-for-service arm and subsequently switched to capitation)

Mayer 2000Interrupted time series with data analysed at limited time points between the interventions

Mellor 1994Observational study on the resource costs of capitation maintenance care (extension of the capitation arm of the Coventry 1989 study)

Mellor 1997Uncontrolled before-after study (extension of Coventry 1989 study examining patients who had been in the fee-for-service arm and subsequently switched to capitation)

Rosen 1977Cohort study (with two samples of matched patients from dental practices with different payment mechanisms)

 
Summary of findings for the main comparison. Fee-for-service remuneration for encouraging fissure sealant placement for second permanent molars in 12- to 14-year-olds

Population: Dentists seeing children with erupted second permanent molars
Settings: Scotland, in areas representing the four most deprived categories (out of seven) in the Scottish post code based system defining deprivation
Intervention: Fee-for-service remuneration

Control: No specific intervention

OutcomesIllustrative comparative risks (95% CI)Relative effect
(95% CI)
No. of Participants
(studies)
Quality of the evidence
(GRADE)

Assumed riskCorresponding risk

ControlFee-for-service remuneration

Measures of clinical activity: mean percentage of 12- to 14-year-olds receiving fissure sealants for second permanent molars per dentist (weighted by number of children seen) - adjusted1
Follow-up: 18 months
-RD 9.8% higher (1.8% higher to 17.8% higher)3-133 dentists
(1 study)
⊕⊝⊝⊝
very low4

Measures of clinical activity: mean percentage of 12- to 14-year-olds receiving fissure sealants for second permanent molars per dentist (weighted by number of children seen) - unadjusted2
Follow-up: 18 months
26.3% (CI NR)RD 7.1% higher (1.9% lower to 16.1% higher)RR 0.27 (CI NR)133 dentists
(1 study)
⊕⊝⊝⊝

very low4

Healthcare costs: cost-effectiveness of fee-for-service vs. control (reported as the "% change in outcome per £[GBP]" - currency year NR)5
Follow-up: 18 months
-- 0.10 (CI NR)68 dentists
(1 study)
⊕⊝⊝⊝

very low4

CI: Confidence interval; GBP: Pound Sterling; NR: Not reported; RD: Risk difference; RR: Risk ratio

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 1The model adjusted for the baseline dental practice-level covariates (deprivation category for the area of dental practice, number of partners in practice, throughput of 11- to 13-year-olds and the number of restorative fissure sealants placed on first permanent molars at baseline).
2The basis for the assumed risk is the risk in the control group (i.e. the probability of a dentist in the control group fissure sealing a second permanent molar of a 12- to 14-year-old). The corresponding risk (the risk difference) is based on the assumed risk in the control group and the relative effect of the fee-for-service remuneration (the risk ratio).
3Statistically significant at the 5% level.
4 Quality of the evidence
  • Risk of bias: high
  • Inconsistency: undetected (single study)
  • Indirectness: yes

    • The dentists only received the fee-for-service remuneration in the first six months of the study but the data were collected 18 months after the start of the trial. The effects of the fee-for-service remuneration would have been attenuated if 18-month data were analysed
    • The fee-for-service remuneration did not affect National Health Service capitation payments which were GBP 2.76 per month to age 12 and GBP 4.01 thereafter, so it is not possible to show the effect of fee-for-service remuneration compared to capitation (only fee-for-service and capitation compared to capitation)
    • The authors suggested that the dentists may have found it too inconvenient to claim a fee from the research team, rather than via the routine National Health Service channel, which would normally be the route for claiming fee-for-service remuneration
    • The average age at baseline was from 13.2 years in the education arm to 13.3 years in the both fee-for-service and education arm, and the data on fissure sealant placement was collected up to 18 months after this baseline so some of the children may have already started to experience decay if their second permanent molars erupted at around 12 years old. Attempting to place fissure sealants soon after the eruption of second permanent molars is considered preferable to waiting a fairly long time after eruption, so the percentage of children with fissure sealants at the end of the study may have been attenuated (this could apply across all of the study arms). Records of any caries already present or any restorations placed would be useful as this could impact on the proportion of fissure sealants placed i.e. dentists in the study may have placed restorations instead of sealant. The authors noted that only two-thirds of eligible dentists claimed a fee, perhaps due to the fact that the child already had caries in their second permanent molars
    • The dentists were working in deprived areas of Scotland, which would have different levels of need compared to Scotland as a whole
    • The economic evaluation does not take into account the payments from the state (i.e. the fee-for-service remuneration in one arm and the capitation payments in both arms, which would be difficult to include as they are paid for dental care as a whole) so the only costs taken into account are the costs to the dental practices (in terms of staff time and consumables) and the costs to parents. An alternative perspective would be to investigate the cost-effectiveness from the point of view of the state which pays the fee-for-service (in place of the dental practices) and parents

  • Imprecision: potentially - the total sample size is lower than the required sample size calculated by the authors
  • Publication bias: undetected (single study)
  • Large effect: not relevant (applies to studies with no threats to validity)
  • Plausible confounding would change the effect: not relevant (applies to studies with no threats to validity)
  • Dose response gradient: not relevant (applies to studies with no threats to validity)

5Outcome in the incremental cost-effectiveness ratio (ICER) is not specified and can only be assumed to relate to sealant placement
 
Summary of findings 2. Capitation remuneration compared to fee-for-service remuneration for encouraging routine continuing dental care of children

Population: Children undergoing routine continuing dental care at 354 dental practices (the number of dentists varied over time as dentists joined and left dental practices, so the number of dental practices was the stable and primary parameter; the total number of 0- to 15-year-old children was not reported accurately)
Settings: Matched pairs of Health Service administrative areas in England (representing northern urban, commuter suburb and rural communities) and Scotland
Intervention: Capitation remuneration
Comparison: Fee-for-service remuneration

OutcomesIllustrative comparative risks (95% CI)Relative effect
(95% CI)
No. of

participants
(studies)
Quality of

the evidence
(GRADE)

Assumed riskCorresponding risk

Fee-for-service remuneration Capitation remuneration

Measures of health service utilisation: mean number of visits per 0- to 15-year-old
Follow-up: 3 years
Northern urban community: 2.8MD 0.4 lower1-˜ 2250

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 2.3MD 0.4 lower1

Rural community: 2.5MD 0.3 lower

Scottish community: 2.8MD 0.5 lower1

Patient outcomes: mean number of filled teeth

per 0- to 15-year-old
Follow-up: 3 years
Northern urban community: 0.78MD 0.18 lower1-˜ 2250

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 0.34MD 0.03 lower

Rural community: 0.44MD 0.21 lower

Scottish community: 0.91MD 0.28 lower1

Patient outcomes: mean percentage of 0- to 15-year-olds having one or more teeth extracted3
Follow-up: 3 years
Northern urban community: 18%RD 5% lower1RR 28% lower1˜ 2250

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 7%RD 0%RR 0%

Rural community: 10%RD 3% lower1RR 30% lower1

Scottish community: 15%RD1% lowerRR 7% lower

Patient outcomes: mean number of decayed teeth per 14- to 15-year-old (data for 0- to 15-year-olds NR)
Follow-up: 3 years
Northern urban community: 0.16MD 0.16 higher-1919

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 0.24MD 0.07 higher

Rural community: 0.58MD 0.75 higher2

Scottish community: 0.65MD 0.15 higher

Measures of clinical activity: mean percentage of 0- to 15-year-olds receiving active preventive advice3
Follow-up: 3 years
Northern urban community: 19%RD 27% higher1RR 142% higher1˜ 2250

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 18%RD 15% higherRR 83% higher

Rural community: 34%RD 5% lowerRR 15% lower

Scottish community: 28%RD 9% higherRR 32% higher

Healthcare costs: mean expenditure in GBP (currency year NR)

per 0- to 15-year-old5
Follow-up: 1 year
Northern urban community: 20.55MD 4.22 higher21% higher276,4145

(1 study4)
⊕⊕⊝⊝

low6

Commuter suburb community: 16.67MD 6.18 higher37% higher

Rural community: 17.29MD 6.90 higher40% higher

Scottish community: 17.68MD 1.52 higher9% higher

CI: Confidence interval; GBP: Pound Sterling; MD: Mean difference; NR: Not reported; RD: Risk difference; RR: Risk ratio

GRADE Working Group grades of evidence
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Very low quality: We are very uncertain about the estimate.

 1Statistically significant at the 5% level. However, the unit of analysis (e.g. dentists, patients, parents and administrators) was often not the same as the unit of randomisation. This leads to unit-of-analysis error, where P values are artificially small (though the estimates of effect are unbiased), leading to false positive conclusions that the intervention had an effect.
2Statistically significant at the 1% level. However, the unit of analysis (e.g. dentists, patients, parents and administrators) was often not the same as the unit of randomisation. This leads to unit-of-analysis error, where P values are artificially small (though the estimates of effect are unbiased), leading to false positive conclusions that the intervention had an effect.
3The basis for the assumed risk is the risk in the control group (i.e. the probability of a dentist in the control group giving preventive advice to or extracting a tooth for a 0- to 15-year-old). The corresponding risk (the risk difference) is based on the assumed risk in the control group and the relative effect of the capitation remuneration (the risk ratio).
4There were four matched pair of Health Service administrative areas. These randomised pairs were treated as separate, thus the overall study contained four replicates under contrasting socioeconomic and environmental circumstances. There were only two Health Service administrative areas randomised in each replicate, therefore each arm of each replicate only contained one Health Service administrative area.
5 All payments made to study dentists for the treatment of 0- to 5-year-olds during 1988 were divided by the estimated numbers of children treated. However, the estimated number is only an approximation as it was impossible to eliminate double-counting, particularly in the fee-for-service system. This means that the mean expenditure per 0- to 15-year-old should only be considered as close approximations, and there is bias that places the capitation arm at a disadvantage. In addition, participating dentists in capitation areas referred significantly more children to the Community Dental Service compared to dentists in fee-for-service areas; this is despite the fact that non-participating dentists in the capitation areas tended to refer significantly fewer children compared to non-participating dentists in fee-for-service areas. The cost of treating the children in the Community Dental Service would not have been taken into account in the economic analysis.
6 Quality of the evidence
  • Risk of bias: high
  • Inconsistency: undetected (single study)
  • Indirectness: no
  • Imprecision: undetected (95% CIs were not reported)
  • Publication bias: undetected (single study)
  • Large effect: not relevant (applies to studies with no threats to validity)
  • Plausible confounding would change the effect: not relevant (applies to studies with no threats to validity)
  • Dose response gradient: not relevant (applies to studies with no threats to validity)