The appraisal of public health interventions: an overview.

BACKGROUND: The approach currently used to appraise public health interventions is close to that of health technology appraisal for drugs. This approach is not appropriate for many public health interventions, however, when extremely small individual level benefits are delivered to extremely large populations. In many such situations, randomized controlled trials with sufficient size and power to determine individual level effects are impractical. Such interventions may be cost-effective, even in the absence of traditional evidence to demonstrate this. METHODS: We outline an alternative approach based on decision theory. We apply it to cases where prior beliefs are sufficiently strong and well grounded to allow decision-makers to assume the direction of change of the intervention's outcome, within the context of a transparent and deliberative decision-making process. Decision theory also assumes that decision-makers are risk neutral, implying that they should make decisions based on an intervention's mean cost-effectiveness, and should therefore disregard variance except when deciding to wait for more information. However, they must allow for biases. RESULTS: A framework is presented which has the potential to achieve large health gains at no additional cost. CONCLUSIONS: This analysis provides a rigorous theoretical framework for decision-makers in public health. The implied paradigm shift also applies to some clinically based areas.

A conceptual framework for public health: NICE's emerging approach.

This paper outlines the National Institute for Health and Clinical Excellence's (NICE) emerging conceptual framework for public health. This is based on the experience of the first 3 years of producing public health guidance at NICE (2005-2008). The framework has been used to shape the revisions to NICE's public health process and methods manuals for use post 2009, and will inform the public health guidance which NICE will produce from April 2009. The framework is based on the precept that both individual and population patterns of disease have causal mechanisms. These are analytically separate. Explanations of individual diseases involve the interaction between biological, social and related phenomena. Explanations of population patterns involve the same interactions, but also additional interactions between a range of other phenomena working in tandem. These are described. The causal pathways therefore involve the social, economic and political determinants of health, as well as psychological and biological factors. Four vectors of causation are identified: population, environmental, organizational and social. The interaction between the vectors and human behaviour are outlined. The bridge between the wider determinants and individual health outcomes is integration of the life course and the lifeworld.

Gastroprotectants in small animal veterinary practice - a review of the evidence. Part 1: cyto-protective drugs.

Diverse drugs with presumed cytoprotective effect have been used therapeutically in small animal veterinary practice for various gastro-intestinal conditions such as oesophagitis, gastric ulceration, gastritis or chronic gastro-enteropathies. Their efficacy has been doubted in human medicine, raising similar questions in the veterinary field. The aim of this review was to assess the current evidence on the efficacy and safety of these drugs in dogs and cats. Through a systematic review of the literature, we identified 37 articles on the use of misoprostol, sucralfate and other gastroprotectants in dogs and cats. There was evidence to support use of misoprostol in the prevention of aspirin-induced gastroduodenal mucosal injury in dogs, and for use of sucralfate in the prevention of acid-induced oesophagitis in cats. However, the overall quality of evidence supporting the use of these drugs in small animal patients was poor. In contrast, there was evidence of important adverse effects, especially drug interaction and gastro-intestinal signs. We therefore recommend prescribing these drugs with caution until further well-conducted studies reveal a useful gastroprotectant effect.

General dental practitioner's views on dental general anaesthesia services.

OBJECTIVE: Policy has recently changed on provision of dental general anaesthetic services in England. The aim of this study was to investigate general dental practitioners' views about dental general anaesthetics, the reduction in its availability and the impact on care of children with toothache. RESEARCH DESIGN: Qualitative study using semi-structured interviews and clinical case scenarios. PARTICIPANTS: General dental practitioners providing NHS services in the North West of England. RESULTS: 93 general dental practitioners were interviewed and 91 answered a clinical case scenario about the care they would provide for a 7-year-old child with multiple decayed teeth presenting with toothache. Scenario responses showed variation; 8% would immediately refer for general anaesthesia, 25% would initially prescribe antibiotics, but the majority would attempt to either restore or extract the tooth causing pain. Interview responses also demonstrated variation in care, however most dentists agree general anaesthesia has a role for nervous children but only refer as a last resort. The responses indicated an increase in inequalities, and that access to services did not match population needs, leaving some children waiting in pain. CONCLUSIONS: Most general dental practitioners support moving dental general anaesthesia into hospitals but some believe that it has widened health inequalities and there is also a problem associated with variation in treatment provision. Additional general anaesthetic services in some areas with high levels of tooth decay are needed and evidence based guidelines about caring for children with toothache are required.

The effectiveness of school dental screening: a cluster-randomized control trial.

Dental screening of children in schools is undertaken in many countries. There is no evidence that this activity is effective. The objective of our study was to determine if school dental screening of children reduces untreated disease or improves attendance at the population level. A four-arm cluster-randomized controlled trial was undertaken in the northwest of England. In total, 16,864 children aged 6-9 years in 168 schools were randomly allocated to 3 test groups, which received screening according to different models, and a control, which received no intervention. There were no significant differences in caries increment in the primary and secondary dentitions or in the proportions of children attending a dentist after screening between the control group and the 3 intervention arms. School dental screening delivered according to 3 different models was not effective at reducing levels of active caries and increasing attendance in the population under study.

A survey of school dental screening practise in community dental services of England and Wales in 2003.

OBJECTIVE: To describe the school dental screening process in Community Dental Services across England and Wales. BASIC RESEARCH DESIGN: Cross-sectional study using a postal questionnaire. CLINICAL SETTING: Community Dental Services. PARTICIPANTS: Clinical Directors of Community Dental Services in England and Wales. MAIN OUTCOME MEASURES: Respondents answers about the objectives of school dental screening, criteria used for referring a child, methods of informing parents of screening results, and methods used to confirm subsequent dental attendance. RESULTS: The response rate for this study was 92.1%. Respondents identified dental registration (75.2%) and attendance at a dentist (82.9%) as objectives of school dental screening. Less than one third (29.5%) saw the activity as having a preventive role. Caries in the primary and secondary dentitions and soft tissue lesions were reported as key criteria for referral. Methods of follow-up of screened positive children differed and were often inadequate; approximately one third of respondents used a letter carried home by the child that did not allow parents to inform the CDS of action taken. Half of the respondents routinely collected data on the number of screened positive children who subsequently visit a dentist. CONCLUSIONS: School dental screening is delivered in a similar fashion throughout England and Wales but methods of informing parents of a positive screen and follow-up mechanisms for children with positive screens vary. Most school dental screening programmes do not collect sufficient data to evaluate the impact of their programmes on children's oral health.

The effectiveness of school dental screening: dental attendance and treatment of those screened positive.

OBJECTIVE: To determine dental attendance and treatment outcomes following two models of dental screening. DESIGN: An observational prospective cohort study. SETTING: Infant, primary and junior schools in the North West of England. SUBJECTS: Children aged six to nine years at the start of the study. INTERVENTIONS: Subjects received a screening examination according to either a 'Traditional model' or 'New model' of school dental screening. MAIN OUTCOME MEASURES: Attendance at a dentist within four months of the intervention and treatment received by children referred via the 'New model' with caries in their permanent teeth. RESULTS: In the 'New model' of school dental screening 46% of screened positive and 41% of screened negative children attended a dentist during the study period. Some 44% of children referred with caries in permanent teeth attended a dentist and 53% of those attending received treatment for the referred condition. Larger proportions of children from disadvantaged backgrounds were screened positive but higher proportions of children from more affluent backgrounds attended the dentist and subsequently received treatment. CONCLUSION: School dental screening has a minimal impact on dental attendance and only a small proportion of screened positive children receive appropriate treatment. The programme fails to reduce inequalities in utilisation of dental services.

Fluoridated milk for preventing dental caries.

BACKGROUND: Dental caries remains a major public health problem in most industrialised countries, affecting 60% to 90% of school children and the vast majority of adults. Milk provides a relatively cost-effective vehicle for fluoride in the prevention of dental caries. OBJECTIVES: To determine the effectiveness of fluoridated milk, as a means of delivering fluoride on a community basis, for preventing dental caries. SEARCH STRATEGY: We searched Cochrane Oral Health Group Trials Register (28 April 2005), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2005), MEDLINE (1966 to 17 May 2005), OLDMEDLINE (1950 to 1965), EMBASE (1980 to 2005 week 20), LILACS (1982 to 17 May 2005), BBO (1986 to 17 May 2005), SIGLE (1980 to 17 May2005), Digital Dissertations (1861 to 17 May 2005) and reference lists of relevant articles. Attempts were made to identify both unpublished and ongoing studies. There were no language restrictions. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials (RCTs), with an intervention or follow-up period of at least 3 years, comparing fluoridated milk with non-fluoridated milk. Primary outcome was change in caries experience, as measured by changes in decayed, missing and filled figures on tooth (dmft/DMFT) and surface (dmfs/DMFS). DATA COLLECTION AND ANALYSIS: Inclusion decisions, data extraction and quality assessment were carried out independently and in duplicate. Study authors were contacted for additional information where necessary. MAIN RESULTS: Two RCTs involving 353 children were included. For permanent teeth, after 3 years there was a significant reduction in the DMFT (78.4%, P < 0.05) between the test and control groups in one trial, but not in the other. The latter study only showed a significant reduction in the DMFT until the fourth (35.5%, P < 0.02) and fifth (31.2%,P < 0.05) years. For primary teeth, again there was a significant reduction in the dmft (31.3%, P< 0.05) between the test and control groups after 3 years in one study, but not in the other. The results could not be pooled because of the difference in concentration of fluoride in the milk. AUTHORS' CONCLUSIONS: There are insufficient studies with good quality evidence examining the effects of fluoridated milk in preventing dental caries. However, the included studies suggested that fluoridated milk was beneficial to school children, especially their permanent dentition. The data need to be supplemented by further RCTs to provide the highest level of evidence for practice.

General dental practitioners' views on the use of stainless steel crowns to restore primary molars.

AIM: To ascertain general dental practitioners' views on the use of stainless steel (pre-formed metal) crowns to restore carious primary molars. METHOD: Ninety-three general dental practitioners were selected at random from those practising in Lancashire, Cheshire and Greater Manchester in 2003 and interviewed separately about the clinical care they provide to the primary dentition. Before the interview participants recorded the care they would provide for a case scenario, describing a child with a carious lesion that the British Society of Paediatric Dentistry (BSPD) guidelines indicate should be treated with a stainless steel crown. RESULTS: In answering the case scenario only six (7%) of the dentists reported that they would fit a stainless steel crown. Of the 93 dentists interviewed 71% knew of the BSPD guidelines, but only 18% had ever fitted a stainless steel crown in general practice. Reasons given for not using stainless steel crowns were they are inappropriate for many children, time consuming to fit, difficult to manipulate, expensive, and ugly. CONCLUSION: The BSPD guidelines on the use of stainless steel crowns do not reflect the views of the majority of general dental practitioners who consider these crowns unsuitable for most children and an impractical restorative technique in busy daily practice.

Possible link between extraction of wisdom teeth and temporomandibular disc displacement with reduction: matched case control study.

We undertook a case control study that compared 220 patients diagnosed with disc displacement with reduction at the Dental Hospital of Manchester with 1100 controls drawn from participants in the 1998 Adult Dental Health Survey. We found that patients were not significantly more likely to have had extraction of third molars than controls; odds ratio: 1.28, 95% CI: 0.96-1.71. Also only 21 patients (9.5%) reported having had extraction of third molars in the 5 years before their diagnosis. We conclude that for most patients extraction of third molars is unlikely to have caused disc displacement with reduction.

Screening by mammography, women with a family history of breast cancer.

The aim of this study was to describe the experience of screening women under the age of 50 years with a family history of breast cancer. 1259 women attended the Family History Clinic in Manchester for their first and subsequent consultations between 30 September 1992 and 30 April 1997. All women were under the age of 50 years at the initial consultation and had a lifetime risk of breast cancer of 1 in 6 or greater. Seven prevalent, seven incident and two interval cancers were detected. The number of invasive cancers expected to occur if this high risk population had not been screened was 8.45 (in 2722 person years at risk). 12 invasive cancers were detected, giving a ratio of 1.42 (95% confidence interval 0.73-2.48). The overall cancer detection rates in this young, at risk population were similar to those in older women in the National Health Service Breast Screening Programme. The number of cancers detected in the study was greater than expected in this population. As the numbers were small, a national trial needs to be undertaken to confirm these results and to determine the long term effects of screening.

Reliability of underlying incidence rates for estimating the effect and efficiency of screening for breast cancer.

The process of setting screening performance targets requires an estimate of what the incidence of breast cancer would have been in the population invited for screening if there had not been a screening programme. Before the introduction of the National Health Service breast screening programme in 1988 the incidence of breast cancer was already increasing in the population targeted for screening. To establish the incidence before screening the most recent complete data from all the regional cancer registries were collated. An age-period model was constructed to predict what these incidence rates might now have been if the screening programme had not been introduced. The model predicted that if prescreening trends continued (between 1987 and 1995) underlying incidence over this period would increase by 2.3 per 10,000 in women aged 50-54, 2.6 per 10,000 in women aged 55-59, and 2.9 per 10,000 in women aged 60-64. If the prescreening trends have continued then the use of a universal rate, applied across all calendar years and age groups, would seem to be inappropriate when setting targets.

Is the three year breast screening interval too long? Occurrence of interval cancers in NHS breast screening programme's north western region.

OBJECTIVE: To report the detection rate of interval cancers in women screened by the NHS breast screening programme. DESIGN: Detection of interval cancers by computer linkage of records held by the screening centres in the North Western Regional Health Authority with breast cancer registrations at the regional cancer registry. SETTING: North Western Regional Health Authority. SUBJECTS: 137,421 women screened between 1 March 1988 and 31 March 1992 who had a negative screening result. RESULTS: 297 invasive interval cancers were detected. The rate of detection of interval cancers expressed as a proportion of the underlying incidence was 31% in the first 12 months after screening, 52% between 12 and 24 months, and 82% between 24 and 36 months. CONCLUSION: The incidence of interval cancers in the third year after breast screening approaches that which would have been expected in the absence of screening and suggests that the three year interval between screens is too long.

Cost effectiveness of shortening screening interval or extending age range of NHS breast screening programme: computer simulation study.

OBJECTIVE: To compare the cost effectiveness of two possible modifications to the current UK screening programme: shortening the screening interval from three to two years and extending the age of invitation to a final screen from 64 to 69. DESIGN: Computer simulation model which first simulates life histories for women in the absence of a screening programme for breast cancer and then assesses how these life histories would be changed by introducing different screening policies. The model was informed by screening and cost data from the NHS breast screening programme. SETTING: North West region of England. MAIN OUTCOME MEASURES: Numbers of deaths prevented, life years gained, and costs. RESULTS: Compared with the current breast screening programme both modifications would increase the number of deaths prevented and the number of life years saved. The current screening policy costs 2522 pounds per life year gained; extending the age range of the programme would cost 2612 pounds and shortening the interval 2709 pounds per life year gained. The marginal cost per life year gained of extending the age range of the screening programme is 2990 pounds and of shortening the screening interval is 3545 pounds. CONCLUSIONS: If the budget for the NHS breast screening programme were to allow for two more invitations per woman, substantial mortality reductions would follow from extending the age range screened or reducing the screening interval. The difference between the two policies is so small that either could be chosen.