Tanya Walsh

Methodological problems in the use of indirect comparisons for evaluating healthcare interventions: survey of published systematic reviews

Objective To investigate basic assumptions and other methodological problems in the application of indirect comparison in systematic reviews of competing healthcare interventions. Design Survey of published systematic reviews. Inclusion criteria Systematic reviews published between 2000 and 2007 in which an indirect approach had been explicitly used. Data extraction Identified reviews were assessed for comprehensiveness of the literature search, method for indirect comparison, and whether assumptions about similarity and consistency were explicitly mentioned. Results The survey included 88 review reports. In 13 reviews, indirect comparison was informal. Results from different trials were naively compared without using a common control in six reviews. Adjusted indirect comparison was usually done using classic frequentist methods (n=49) or more complex methods (n=18). The key assumption of trial similarity was explicitly mentioned in only 40 of the 88 reviews. The consistency assumption was not explicit in most cases where direct and indirect evidence were compared or combined (18/30). Evidence from head to head comparison trials was not systematically searched for or not included in nine cases. Conclusions Identified methodological problems were an unclear understanding of underlying assumptions, inappropriate search and selection of relevant trials, use of inappropriate or flawed methods, lack of objective and validated methods to assess or improve trial similarity, and inadequate comparison or inappropriate combination of direct and indirect evidence. Adequate understanding of basic assumptions underlying indirect and mixed treatment comparison is crucial to resolve these methodological problems. Appendix 1 PubMed search strategy Appendix 2 Characteristics of identified reports Appendix 3 Identified studies References of included studies

Cochrane Reviews on the Benefits/Risks of Fluoride Toothpastes:

This concise review presents two Cochrane Reviews undertaken to determine: (1) the relative effectiveness of fluoride toothpastes of different concentrations in preventing dental caries in children and adolescents; and (2) the relationship between the use of topical fluorides in young children and their risk of developing dental fluorosis. To determine the relative effectiveness of fluoride toothpastes of different concentrations, we undertook a network meta-analysis utilizing both direct and indirect comparisons from randomized controlled trials (RCTs). The review examining fluorosis included evidence from experimental and observational studies. The findings of the reviews confirm the benefits of using fluoride toothpaste, when compared with placebo, in preventing caries in children and adolescents, but only significantly for fluoride concentrations of 1000 ppm and above. The relative caries-preventive effects of fluoride toothpastes of different concentrations increase with higher fluoride concentration. However, there is weak, unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis. The decision of what fluoride levels to use for children under 6 years should be balanced between the risk of developing dental caries and that of mild fluorosis.

A Cluster-randomized Controlled Trial: Fluoride Varnish in School Children

We conducted a school-based parallel cluster randomized controlled trial with 36-month follow-up of children aged 7 to 8 years. Primary schools were randomly assigned to 2 groups: 3 applications of fluoride varnish (22,600 ppm) each year or no intervention. The primary outcome was DFS increment in the first permanent molars, with the hypothesis that 9 applications of varnish over 3 years would result in a lower increment in the test group. Follow-up measurements were recorded by examiners blind to the allocation. Ninety-five schools were randomized to the test and 95 to the reference groups; 1473 (test) and 1494 (reference) children participated in the trial. An intention-to-treat analysis was carried out with random effects models. The DFS increment was 0.65 (SD 2.15) in the test and 0.67 (SD 2.10) in the reference groups, respectively. There was no statistically significant difference between the groups. We were unable to demonstrate an effect for fluoride varnish when it was used as a public health intervention to prevent caries in the first permanent molar teeth (Inter-national Standard Randomized Controlled Trial Registration: ISRCTN: #72589426)

Is early class III protraction facemask treatment effective? A multicentre, randomized, controlled trial: 15‐month follow‐up

OBJECTIVE To investigate the effectiveness of early class III protraction facemask treatment in children under 10 years of age at 3-year follow-up. DESIGN Multicentre randomized controlled trial. SUBJECTS AND METHODS Seventy-three patients were randomly allocated, stratified for gender, into early class III protraction facemask group (PFG) (n = 35) and a control/no treatment group (CG) (n = 38). OUTCOMES Dentofacial changes were assessed from lateral cephalograms and occlusal changes using the peer assessment rating (PAR). Self-esteem was assessed using the Piers-Harris childrens self-concept scale, and the psychosocial impact of malocclusion with oral aesthetic subjective impact score (OASIS) questionnaire. Temporomandibular joint (TMJ) signs and symptoms were also recorded. The time points for data collection were at registration (DC1), 15 months later (DC2) and 3 years post-registration (DC3). RESULTS The following mean skeletal and occlusal changes occurred from the class III starting point to DC3 (3-year follow-up): SNA, PFG moved forwards +2·3° (CG forward +1·6°; P = 0·14); SNB, PFG moved forwards +0·8° (CG forward +1·5°, P = 0·26); ANB, PFG class III base improved +1·5° (CG stayed about the same at +0·1°; P = 0·001). This contributed to an overall difference in ANB between PFG and CG of +1·4° in favour of early protraction facemask treatment. The overjet was still improved by +3·6 mm in the PFG and changed a small amount +1·1 mm in the CG (P = 0·001). A 21% improvement in PAR was shown in the PFG and the CG worsened by 8·4% (P = 0·02). There was no increase in self-esteem (Piers-Harris score) for PFG compared with the CG (P = 0·56) and no statistically significant difference in the impact of malocclusion (OASIS) between groups in terms of the changes from DC1 to DC3 (P = 0·18). TMJ signs and symptoms were very low at DC1 and DC3. CONCLUSIONS The favourable effect of early class III protraction facemask treatment undertaken in patients under 10 years of age, is maintained at 3-year follow-up in terms of ANB, overjet and % PAR improvement. The direct protraction treatment effect at SNA is still favourable although not statistically significantly better than the CG. Seventy per cent of patients in PFG had maintained a positive overjet which we have defined as ongoing treatment success. Early protraction facemask treatment does not seem to influence self-esteem or reduce the patients personal impact of their malocclusion at 3-year follow-up.

Prospective, multi-center study of the effectiveness of orthodontic/orthognathic surgery care in the United Kingdom

INTRODUCTION The aim of this study was to evaluate the effectiveness of orthodontic/orthognathic surgical care provided in the North West region of England. It was an observational, prospective cohort study at 13 maxillofacial clinics in the United Kingdom. METHODS The 131 patients comprised 47 males (35.9%) and 84 females (64.1%), with an average age of 22.6 years. They received orthodontic/orthognathic treatment according to the normal protocols of the operators. They were then followed until all orthodontic treatment was completed. Final skeletal pattern, final peer assessment rating score, number of attendances, and duration of treatment were recorded. RESULTS At the end of the 5-year study, 94 patients had completed treatment, and 71 had complete data. Data analysis showed that, overall, the treatments provided were effective in terms of skeletal and dental occlusal outcomes; the final mean peer assessment rating score was 10.58. However, treatment duration was longer than commonly expected, with a mean length of 32.8 months (SD,11.3). The outcome of treatment was influenced by only pretreatment skeletal discrepancy. CONCLUSIONS This prospective investigation showed that orthodontic/orthognathic surgical care was effective. The outcome of treatment was influenced only by the severity of the pretreatment skeletal discrepancy.

Split-mouth designs in orthodontics: An overview with applications to orthodontic clinical trials

Split-mouth designs first appeared in dental clinical trials in the late sixties. The main advantage of this study design is its efficiency in terms of sample size as the patients act as their own controls. Cited disadvantages relate to carry-across effects, contamination or spilling of the effects of one intervention to another, period effects if the interventions are delivered at different time periods, difficulty in finding similar comparison sites within patients and the requirement for more complex data analysis. Although some additional thought is required when utilizing a split-mouth design, the efficiency of this design is attractive, particularly in orthodontic clinical studies where carry-across, period effects and dissimilarity between intervention sites does not pose a problem. Selection of the appropriate research design, intervention protocol and statistical method accounting for both the reduced variability and potential clustering effects within patients should be considered for the trial results to be valid.

Tooth loss and osteoporosis: to assess the association between osteoporosis status and tooth number.

Background Osteopenia and osteoporosis are conditions characterised by a reduction in bone mineral density. There is contradictory evidence whether osteoporotic patients have greater tooth loss than non-osteoporotic patients.Objective To investigate the association between tooth number and osteoporotic status, taking into account the effect of other confounding variables such as age, smoking status, alcohol consumption and the use of hormone replacement therapy.Setting Three hundred and fifty-nine patients were recruited from the Manchester region between March 2008 and June 2010.Subjects and methods Data were collected on osteoporotic status, smoking status, alcohol consumption, age and the use of hormone replacement therapy. Dental panoramic tomographs were taken for each patient and the teeth present were charted and counted. Data were analysed using SPSS software (version 19).Results Complete data was available for 333 patients. Twenty-seven percent of individuals (90) were classified as osteoporotic. There was a significant relationship between molar tooth number and osteoporotic status (p = 0.017, 95% CI −1.339 to −0.137).Conclusion Clinicians should inform osteoporotic patients they may be at greater risk of tooth loss and instigate more intensive preventive regimens for these individuals.

The Efficacy of Screening for Common Dental Diseases by Hygiene-Therapists A Diagnostic Test Accuracy Study

Regularly attending adult patients are increasingly asymptomatic and not in need of treatment when attending for their routine dental examinations. As oral health improves further, using the general dental practitioner to undertake the “checkup” on regular “low-risk” patients represents a substantial and potentially unnecessary cost for state-funded systems. Given recent regulatory changes in the United Kingdom, it is now theoretically possible to delegate a range of tasks to hygiene-therapists. This has the potential to release the general dental practitioner’s time and increase the capacity to care. The aim of this study is to compare the diagnostic test accuracy of hygiene-therapists when screening for dental caries and periodontal disease in regularly attending asymptomatic adults who attend for their checkup. A visual screen by hygiene-therapists acted as the index test, and the general dental practitioner acted as the reference standard. Consenting asymptomatic adult patients, who were regularly attending patients at 10 practices across the Northwest of England, entered the study. Both sets of clinicians made an assessment of dental caries and periodontal disease. The primary outcomes measured were the sensitivity and specificity values for dental caries and periodontal disease. In total, 1899 patients were screened. The summary point for sensitivity of dental care professionals when screening for caries and periodontal disease was 0.81 (95% CI, 0.74 to 0.87) and 0.89 (0.86 to 0.92), respectively. The summary point for specificity of dental care professionals when screening for caries and periodontal disease was 0.87 (0.78 to 0.92) and 0.75 (0.66 to 0.82), respectively. The results suggest that hygiene-therapists could be used to screen for dental caries and periodontal disease. This has important ramifications for service design in public-funded health systems.

Comparison of photographic and visual assessment of occlusal caries with histology as the reference standard

BackgroundThe purpose of this study was to compare diagnostic performance for the detection of caries using photographs with an established visual examination method and histological sections as the reference standard.Methods50 extracted permanent teeth were assessed for the presence of occlusal caries by 9 examiners using two methods; traditional visual examination developed by BASCD and photographs produced by an intra-oral camera. For both methods, diagnoses were made at “caries into dentine” level. The teeth were histologically sectioned and the diagnostic decisions using visual and photographic assessment were compared to the histological reference standard. Inter- and intra- examiner reliability for the methods was assessed and weighted kappa values were calculated.ResultsThe visual examination method had a median sensitivity value of 65.6% and a median specificity value of 82.4%. The photographic assessments method had a median sensitivity of 81.3% and a median specificity of 82.4%.ConclusionsThe photographic assessments method had a higher sensitivity for caries detection than the visual examination. The two methods had comparable specificities and good intra- and inter- examiner reliability.

Comparison of Twin-block and Dynamax appliances for the treatment of Class II malocclusion in adolescents: a randomized controlled trial.

INTRODUCTION The aim of this study was to compare the effectiveness of Twin-block and Dynamax appliances for the treatment of Class II Division 1 malocclusion. METHODS This was a randomized controlled trial involving 32 boys and 32 girls aged 10 to 14 years with Class II Division 1 malocclusion. They were randomly allocated to either the Dynamax appliance group or the Twin-block appliance group. Treatment was provided by 4 clinicians at 2 centers. Records were taken at the start and the end of the functional phase and after all treatment. In addition, incisal overjet, the number of appliance breakages, and adverse events or side effects of the treatment were recorded at each patient visit. RESULTS The data monitoring committee in an interim analysis at 18 months after the start of the trial found significantly greater overjet reduction in the Twin-block group than in the Dynamax group and more breakages and adverse events with the Dynamax appliance. As a result, treatment with the Dynamax appliance was terminated, and those patients completed treatment with the Twin-block or a fixed appliance. Regression analysis showed a statistically significant difference in the performance over time between the Twin-block and Dynamax appliances in terms of reduction in overjet, with the Twin-block appliance performing significantly better than the Dynamax. The incidence of adverse events was greater in the Dynamax group (82%) than in the Twin-block group (16%), with a statistically significant difference (P <0.001) between the 2 groups. CONCLUSIONS The Twin-block appliance was more effective than the Dynamax appliance when overjet was evaluated and the Dynamax appliance patients reported greater incidence of adverse events with their appliance than those who were treated with the Twin-block appliance.