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Papers by d. koletsi

Research paper thumbnail of Most Healthcare Interventions Tested in Cochrane Reviews are Not Effective According to High Quality Evidence: A Meta-Epidemiological Study

SSRN Electronic Journal, 2022

Research paper thumbnail of A priori power considerations in Endodontic Research. Do we miss the timeline?

International Endodontic Journal, 2021

AIM To record the prevalence of a priori power calculations in the manuscripts published in three... more AIM To record the prevalence of a priori power calculations in the manuscripts published in three endodontic journals between 2018 and 2020 and detect further associations with a number of study characteristics including journal, publication year, study design, geographic region, number of centres and authors, whether the primary outcome pertained to a statistically significant effect and whether Confidence Intervals (CIs) were reported. METHODOLOGY The contents of the three leading endodontic journals with the highest impact factor (International Endodontic Journal, IEJ; Journal of Endodontics, JOE; and Australian Endodontic Journal, AEJ) were assessed from January 2018 to December 2020. The proportion of articles reporting a priori power calculations were recorded, and relevant associations as described above were assessed. Univariable and multivariable logistic regression were used to identify significant predictors, while interaction and linear trend effects were also considered. RESULTS A total of 716 original research articles were included. The vast majority were published in the JOE (417/716; 58.2%), followed by the IEJ (225/716; 31.4%) and the AEJ (74/716; 10.4%). Overall, a priori power considerations were reported in 243 out of 716 articles (33.9%). The IEJ presented 1.61 times higher odds for including a priori power considerations compared to JOE (adjusted Odds Ratio, OR=1.61; 95%CI: 1.11, 2.34), while for the AEJ, the corresponding odds were 41% lower in comparison to JOE (adjusted OR= 0.59; 95%CI: 0.31, 1.14). For each additional year indicating more recent publication, the odds for adopting appropriate reporting practices for power considerations were increased by 64% (adjusted OR= 1.64; 95CIs: 1.32, 2.04). There was strong evidence that interventional research was associated with 10.54 times higher odds for a priori considerations compared to observational study design (adjusted OR= 10.54; 95%CIs: 5.50, 20.19). CONCLUSIONS The high prevalence of failure to include a priori power considerations was indicative of suboptimal reporting in endodontic research, in the three endodontic journals analysed. Although the condition improved over time, efforts to incorporate a correct determination of the required sample size at the design stage for any future study should be endorsed by journal editors, authors and the scientific community.

Research paper thumbnail of Direct pulp capping in asymptomatic carious primary molars using three different pulp capping materials: a prospective clinical trial

European Archives of Paediatric Dentistry

Research paper thumbnail of Most healthcare interventions tested in Cochrane Reviews are not effective according to high quality evidence: a systematic review and meta-analysis

Journal of Clinical Epidemiology, 2022

Objective: To estimate the proportion of healthcare interventions tested within Cochrane Reviews ... more Objective: To estimate the proportion of healthcare interventions tested within Cochrane Reviews that are effective according to highquality evidence. Methods: We selected a random sample of 2,428 (35%) of all Cochrane Reviews published between 1 January 2008 and 5 March 2021. We extracted data about interventions within these reviews that were compared with placebo, or no treatment, and whose outcome quality was rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We calculated the proportion of interventions whose benefits were based on high-quality evidence (defined as having high quality GRADE rating for at least one primary outcome, statistically significant positive results, and being judged by review authors as effective. We also calculated the proportion of interventions that suggested harm. Results: Of 1,567 eligible interventions, 87 (5.6%) had high-quality evidence supporting their benefits. Harms were measured for 577 (36.8%) interventions. There was statistically significant evidence for harm in 127 (8.1%) of these. Our dependence on the reliability of Cochrane author assessments (including their GRADE assessments) was the main potential limitation of our study. Conclusion: More than 9 in 10 healthcare interventions studied within recent Cochrane Reviews are not supported by high-quality evidence, and harms are under-reported.

Research paper thumbnail of DS_10.1177_0022034520943574 – Supplemental material for Interventions to Reduce Aerosolized Microbes in Dental Practice: A Systematic Review with Network Meta-analysis of Randomized Controlled Trials

Supplemental material, DS_10.1177_0022034520943574 for Interventions to Reduce Aerosolized Microb... more Supplemental material, DS_10.1177_0022034520943574 for Interventions to Reduce Aerosolized Microbes in Dental Practice: A Systematic Review with Network Meta-analysis of Randomized Controlled Trials by D. Koletsi, G.N. Belibasakis and T. Eliades in Journal of Dental Research

Research paper thumbnail of Conditional logistic regression

Research paper thumbnail of Poisson regression

Research paper thumbnail of The quality of evidence for medical interventions does not improve or worsen: a metaepidemiological study of Cochrane reviews

Journal of Clinical Epidemiology, 2020

We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to ... more We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to document evidence quality. STUDY DESIGN AND SETTING We searched the Cochrane Database of Systematic Reviews on March 20, 2020 to identify which of the reviews from the initial (2013/14) sample had been updated. Using the same methods to determine the quality of evidence in the previous analysis, we assessed the quality of evidence for the first-listed primary outcomes in the updated reviews. RESULTS Of the 608 reviews in the original sample, 154 had been updated with and 151 contained available data for both original and updated systematic reviews (24.8%). The updated reviews included: 15 (9.9%) with high-quality evidence, 56 (37.1%) with moderate-quality evidence, 47 (31.1%) with lowquality evidence, and 33 (21.9%) with very low-quality evidence. No change in the GRADE quality of evidence was found for most (103, 68.2%) of the updated reviews. The quality of evidence rating was downgraded in 28 reviews (58.3%) and upgraded in 20 (41.7%), although only six reviews were promoted to high quality. CONCLUSION Updated systematic reviews continued to suggest that only a minority of outcomes for health care interventions are supported by high-quality evidence. The quality of the evidence did not consistently improve or worsen in updated reviews.

Research paper thumbnail of Survival analysis, part 3: Cox regression

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Conditional logistic regression

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

The estimation procedure used in NCSS makes use of the relationship between CLR and Cox Regressio... more The estimation procedure used in NCSS makes use of the relationship between CLR and Cox Regression. This relationship allows us to estimate and test the significance of the β's using the Cox Regression calculation engine. However, it does not allow the calculation of predicted values and residuals. As discussed in the Cox Regression chapter, there are two methods available for approximating the likelihood equation when there are ties present: Breslow and Efron. The Breslow method is often used as the default in other statistical packages. It is recommended for 1:1 and 1:n matching. Efron's method is general taken to be more accurate, but a little slower to compute. It is recommended for m:n matching where m is greater than one. Statistical Tests and Confidence Intervals Inferences about the regression coefficients are of interest. The inference procedures in Cox regression continue to be valid as long as the sample sizes are adequate. Two tests are available for testing the significance of one or more independent variables in a regression: the likelihood ratio test and the Wald test. Simulation studies usually show that the likelihood ratio test performs better than the Wald test. However, the Wald test is still used to test the significance of individual regression coefficients because of its ease of calculation. These two testing procedures will be described next. Likelihood Ratio and Deviance The Likelihood Ratio test statistic is-2 times the difference between the log likelihoods of two models, one of which is a subset of the other. The distribution of the LR statistic is closely approximated by the chi-square distribution for large sample sizes. The degrees of freedom (DF) of the approximating chi-square distribution is equal to the difference in the number of regression coefficients in the two models. The test is named as a ratio rather than a difference since the difference between two log likelihoods is equal to the log of the ratio of the two likelihoods.

Research paper thumbnail of Matched analysis for paired binary data (McNemar test)

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Survival analysis, part 2: Kaplan-Meier method and the log-rank test

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Survival analysis, part 1: Introduction

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Introduction to incidence rates and time-changing variables for cohort studies

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of The use of tailored subheadings was successful in enhancing compliance with CONSORT in a dental journal

Journal of Dentistry, 2017

Objectives: Efforts to enhance the reporting of clinical trials have intensified in recent years ... more Objectives: Efforts to enhance the reporting of clinical trials have intensified in recent years with automated strategies and editorial involvement showing promise in improving compliance with accepted guidelines. This study aimed to evaluate the effectiveness of a concerted approach to adherence to CONSORT (CONsolidated Standards Of Reporting Trials) guidelines in a dental journal. Materials and Methods: Following the publication of an exemplar clinical trial on the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO) website and related changes to the author guidelines, trial submissions were required to follow a standard format incorporating subheadings mirroring the CONSORT guidelines. Compliance with CONSORT was assessed in initial submissions over a 30-month period. Reporting was compared to submissions of randomized controlled trials (RCTs) which did not include subheadings over the same period. Results: Seventy-one RCTs were submitted to the AJO-DO from January 2014 to June 2016, 49 with subheadings and 22 without. Most CONSORT items (e.g. random sequence generation, allocation concealment and blinding) were more frequently adequately reported when RCTs were submitted with inclusion of subheadings. Overall, reporting quality of the submitted RCTs was 15.2% higher with use of the subheadings format (95%CI: 10.5, 20.0; p<0.001) with a mean overall score of 87.3%. Conclusion: Enhanced compliance of submitted RCTs was found with use of a bespoke approach to trial presentation utilizing CONSORT item subheadings. The improvement in initial submissions is particularly encouraging as this arose without input either from peer reviewers or journal editors. This simple approach may have wider applicability.

Research paper thumbnail of The evidence from systematic reviews and meta-analyses published in orthodontic literature. Where do we stand?

European journal of orthodontics, Jan 8, 2015

Summary AIM : To analyse meta-analyses included in systematic reviews (SRs) published in leading ... more Summary AIM : To analyse meta-analyses included in systematic reviews (SRs) published in leading orthodontic journals and the Cochrane Database of Systematic Reviews (CDSR) focusing on orthodontic literature and to assess the quality of the existing evidence. Electronic searching was undertaken to identify SRs published in five major orthodontic journals and the CDSR between January 2000 and June 2014. Quality assessment of the overall body of evidence from meta-analyses was conducted using the Grading of Recommendations Assessment, Development and Evaluation working group (GRADE) tool. One hundred and fifty-seven SRs were identified; meta-analysis was present in 43 of these (27.4 per cent). The highest proportion of SRs that included a meta-analysis was found in Orthodontics and Craniofacial Research (6/13; 46.1 per cent), followed by the CDSR (12/33; 36.4 per cent) and the American Journal of Orthodontics and Dentofacial Orthopaedics (15/44; 34.1 per cent). Class II treatment was ...

Research paper thumbnail of Statistical testing against baseline was common in dental research

Journal of clinical epidemiology, Jan 12, 2015

To assess the presence of within-group comparisons with baseline in a subset of leading dental jo... more To assess the presence of within-group comparisons with baseline in a subset of leading dental journals and to explore possible associations with a range of study characteristics including journal and study design. Thirty consecutive issues of five leading dental journals were electronically searched. The conduct and reporting of statistical analysis in respect of comparisons against baseline or otherwise along with the manner of interpretation of the results were assessed. Descriptive statistics were obtained, and chi-square test and Fisher's exact were undertaken to test the association between trial characteristics and overall study interpretation. A total of 184 studies were included with the highest proportion published in Journal of Endodontics (n = 84, 46%) and most involving a single center (n = 157, 85%). Overall, 43 studies (23%) presented interpretation of their outcomes based solely on comparisons against baseline. Inappropriate use of baseline testing was found to b...

Research paper thumbnail of Blinded by PRISMA: Are Systematic Reviewers Focusing on PRISMA and Ignoring Other Guidelines?

PLoS ONE, 2014

Background: PRISMA guidelines have been developed to improve the reporting of systematic reviews ... more Background: PRISMA guidelines have been developed to improve the reporting of systematic reviews (SRs). Other reporting guidelines and techniques to assess methodological quality of SRs have been developed. We aimed to assess the frequency of the use of reporting and other guidelines in SRs to assess whether PRISMA is being used inappropriately as a substitute for other relevant guidelines. Methods: Web of Knowledge was searched to identify articles citing the PRISMA guidelines over a 12-month period. The use of reporting guidelines (including PRISMA and MOOSE) and tools for assessing methodological quality (including QUADAS) was assessed. Factors associated with appropriate use of guidelines including review type, field of publication and involvement of a methodologist were investigated. Results: Over the 12-month period, 701 SRs were identified. MOOSE guidelines were cited in just 17% of epidemiologic reviews; QUADAS or QUADAS-2 was referred to in just 40% of diagnostic SRs. In the multivariable analysis, medical field of publication and methodologist involvement (OR = 1.97, 95% CI: 1.37, 2.83) were significant predictors of appropriate use of guidelines. Inclusion of a meta-analysis resulted in 73% higher odds of appropriate usage of systematic review guidelines (OR = 1.73, 95% CI: 1.22, 2.35). Conclusions: Usage of SR reporting guidelines and tools for assessment of methodological quality other than PRISMA may be under-utilized with negative implications both for the reporting and methodological quality of systematic reviews.

Research paper thumbnail of Are Sample Sizes Clear and Justified in RCTs Published in Dental Journals?

PLoS ONE, 2014

Sample size calculations are advocated by the CONSORT group to justify sample sizes in randomized... more Sample size calculations are advocated by the CONSORT group to justify sample sizes in randomized controlled trials (RCTs). The aim of this study was primarily to evaluate the reporting of sample size calculations, to establish the accuracy of these calculations in dental RCTs and to explore potential predictors associated with adequate reporting. Electronic searching was undertaken in eight leading specific and general dental journals. Replication of sample size calculations was undertaken where possible. Assumed variances or odds for control and intervention groups were also compared against those observed. The relationship between parameters including journal type, number of authors, trial design, involvement of methodologist, single-/multi-center study and region and year of publication, and the accuracy of sample size reporting was assessed using univariable and multivariable logistic regression. Of 413 RCTs identified, sufficient information to allow replication of sample size calculations was provided in only 121 studies (29.3%). Recalculations demonstrated an overall median overestimation of sample size of 15.2% after provisions for losses to follow-up. There was evidence that journal, methodologist involvement (OR = 1.97, CI: 1.10, 3.53), multi-center settings (OR = 1.86, CI: 1.01, 3.43) and time since publication (OR = 1.24, CI: 1.12, 1.38) were significant predictors of adequate description of sample size assumptions. Among journals JCP had the highest odds of adequately reporting sufficient data to permit sample size recalculation, followed by AJODO and JDR, with 61% (OR = 0.39, CI: 0.19, 0.80) and 66% (OR = 0.34, CI: 0.15, 0.75) lower odds, respectively. Both assumed variances and odds were found to underestimate the observed values. Presentation of sample size calculations in the dental literature is suboptimal; incorrect assumptions may have a bearing on the power of RCTs.

Research paper thumbnail of Mislabeling Controlled Clinical Trials (CCTs) as “Randomized Clinical Trials (RCTs)” in Dental Specialty Journals

Journal of Evidence Based Dental Practice, 2012

Objectives: This study aimed to investigate whether studies published in dental journals with the... more Objectives: This study aimed to investigate whether studies published in dental journals with the highest impact factor, representing the 5 major dental specialties and titled as randomized clinical trials (RCTs) are truly RCTs. A second objective was to explore the association of journal type and other publication characteristics on correct classification. Methods: The American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), the British Journal of Oral and Maxillofacial Surgery (BJOMS), the International Journal of Prosthodontics (IJP), the Journal of Clinical Periodontology (JCP), and the Journal of Endodontics (JOE) were hand searched for clinical trials labeled in the title as randomized from 1979 to July 2011. The data were analyzed using descriptive statistics, and univariable and multivariable examination of statistical associations via ordinal logistic regression modeling (proportional odds model). Results: A total of 222 trials were identified. From the included trials, 88 (39.64%) were considered to be RCTs, 107 (48.20%) were considered to be of unclear status, and 27 (12.16%) were not considered as RCTs. In the multivariable analysis among the included variables, journal type, involvement of statistician, year of publication, multicenter trial, and number of authors were significant predictors of correctly classifying a study as an RCT versus no RCT and of unclear status. Conclusions: This study indicates the need for clear and accurate reporting of clinical trials and the need for educating investigators on RCT methodology.

Research paper thumbnail of Most Healthcare Interventions Tested in Cochrane Reviews are Not Effective According to High Quality Evidence: A Meta-Epidemiological Study

SSRN Electronic Journal, 2022

Research paper thumbnail of A priori power considerations in Endodontic Research. Do we miss the timeline?

International Endodontic Journal, 2021

AIM To record the prevalence of a priori power calculations in the manuscripts published in three... more AIM To record the prevalence of a priori power calculations in the manuscripts published in three endodontic journals between 2018 and 2020 and detect further associations with a number of study characteristics including journal, publication year, study design, geographic region, number of centres and authors, whether the primary outcome pertained to a statistically significant effect and whether Confidence Intervals (CIs) were reported. METHODOLOGY The contents of the three leading endodontic journals with the highest impact factor (International Endodontic Journal, IEJ; Journal of Endodontics, JOE; and Australian Endodontic Journal, AEJ) were assessed from January 2018 to December 2020. The proportion of articles reporting a priori power calculations were recorded, and relevant associations as described above were assessed. Univariable and multivariable logistic regression were used to identify significant predictors, while interaction and linear trend effects were also considered. RESULTS A total of 716 original research articles were included. The vast majority were published in the JOE (417/716; 58.2%), followed by the IEJ (225/716; 31.4%) and the AEJ (74/716; 10.4%). Overall, a priori power considerations were reported in 243 out of 716 articles (33.9%). The IEJ presented 1.61 times higher odds for including a priori power considerations compared to JOE (adjusted Odds Ratio, OR=1.61; 95%CI: 1.11, 2.34), while for the AEJ, the corresponding odds were 41% lower in comparison to JOE (adjusted OR= 0.59; 95%CI: 0.31, 1.14). For each additional year indicating more recent publication, the odds for adopting appropriate reporting practices for power considerations were increased by 64% (adjusted OR= 1.64; 95CIs: 1.32, 2.04). There was strong evidence that interventional research was associated with 10.54 times higher odds for a priori considerations compared to observational study design (adjusted OR= 10.54; 95%CIs: 5.50, 20.19). CONCLUSIONS The high prevalence of failure to include a priori power considerations was indicative of suboptimal reporting in endodontic research, in the three endodontic journals analysed. Although the condition improved over time, efforts to incorporate a correct determination of the required sample size at the design stage for any future study should be endorsed by journal editors, authors and the scientific community.

Research paper thumbnail of Direct pulp capping in asymptomatic carious primary molars using three different pulp capping materials: a prospective clinical trial

European Archives of Paediatric Dentistry

Research paper thumbnail of Most healthcare interventions tested in Cochrane Reviews are not effective according to high quality evidence: a systematic review and meta-analysis

Journal of Clinical Epidemiology, 2022

Objective: To estimate the proportion of healthcare interventions tested within Cochrane Reviews ... more Objective: To estimate the proportion of healthcare interventions tested within Cochrane Reviews that are effective according to highquality evidence. Methods: We selected a random sample of 2,428 (35%) of all Cochrane Reviews published between 1 January 2008 and 5 March 2021. We extracted data about interventions within these reviews that were compared with placebo, or no treatment, and whose outcome quality was rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. We calculated the proportion of interventions whose benefits were based on high-quality evidence (defined as having high quality GRADE rating for at least one primary outcome, statistically significant positive results, and being judged by review authors as effective. We also calculated the proportion of interventions that suggested harm. Results: Of 1,567 eligible interventions, 87 (5.6%) had high-quality evidence supporting their benefits. Harms were measured for 577 (36.8%) interventions. There was statistically significant evidence for harm in 127 (8.1%) of these. Our dependence on the reliability of Cochrane author assessments (including their GRADE assessments) was the main potential limitation of our study. Conclusion: More than 9 in 10 healthcare interventions studied within recent Cochrane Reviews are not supported by high-quality evidence, and harms are under-reported.

Research paper thumbnail of DS_10.1177_0022034520943574 – Supplemental material for Interventions to Reduce Aerosolized Microbes in Dental Practice: A Systematic Review with Network Meta-analysis of Randomized Controlled Trials

Supplemental material, DS_10.1177_0022034520943574 for Interventions to Reduce Aerosolized Microb... more Supplemental material, DS_10.1177_0022034520943574 for Interventions to Reduce Aerosolized Microbes in Dental Practice: A Systematic Review with Network Meta-analysis of Randomized Controlled Trials by D. Koletsi, G.N. Belibasakis and T. Eliades in Journal of Dental Research

Research paper thumbnail of Conditional logistic regression

Research paper thumbnail of Poisson regression

Research paper thumbnail of The quality of evidence for medical interventions does not improve or worsen: a metaepidemiological study of Cochrane reviews

Journal of Clinical Epidemiology, 2020

We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to ... more We used the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system to document evidence quality. STUDY DESIGN AND SETTING We searched the Cochrane Database of Systematic Reviews on March 20, 2020 to identify which of the reviews from the initial (2013/14) sample had been updated. Using the same methods to determine the quality of evidence in the previous analysis, we assessed the quality of evidence for the first-listed primary outcomes in the updated reviews. RESULTS Of the 608 reviews in the original sample, 154 had been updated with and 151 contained available data for both original and updated systematic reviews (24.8%). The updated reviews included: 15 (9.9%) with high-quality evidence, 56 (37.1%) with moderate-quality evidence, 47 (31.1%) with lowquality evidence, and 33 (21.9%) with very low-quality evidence. No change in the GRADE quality of evidence was found for most (103, 68.2%) of the updated reviews. The quality of evidence rating was downgraded in 28 reviews (58.3%) and upgraded in 20 (41.7%), although only six reviews were promoted to high quality. CONCLUSION Updated systematic reviews continued to suggest that only a minority of outcomes for health care interventions are supported by high-quality evidence. The quality of the evidence did not consistently improve or worsen in updated reviews.

Research paper thumbnail of Survival analysis, part 3: Cox regression

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Conditional logistic regression

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

The estimation procedure used in NCSS makes use of the relationship between CLR and Cox Regressio... more The estimation procedure used in NCSS makes use of the relationship between CLR and Cox Regression. This relationship allows us to estimate and test the significance of the β's using the Cox Regression calculation engine. However, it does not allow the calculation of predicted values and residuals. As discussed in the Cox Regression chapter, there are two methods available for approximating the likelihood equation when there are ties present: Breslow and Efron. The Breslow method is often used as the default in other statistical packages. It is recommended for 1:1 and 1:n matching. Efron's method is general taken to be more accurate, but a little slower to compute. It is recommended for m:n matching where m is greater than one. Statistical Tests and Confidence Intervals Inferences about the regression coefficients are of interest. The inference procedures in Cox regression continue to be valid as long as the sample sizes are adequate. Two tests are available for testing the significance of one or more independent variables in a regression: the likelihood ratio test and the Wald test. Simulation studies usually show that the likelihood ratio test performs better than the Wald test. However, the Wald test is still used to test the significance of individual regression coefficients because of its ease of calculation. These two testing procedures will be described next. Likelihood Ratio and Deviance The Likelihood Ratio test statistic is-2 times the difference between the log likelihoods of two models, one of which is a subset of the other. The distribution of the LR statistic is closely approximated by the chi-square distribution for large sample sizes. The degrees of freedom (DF) of the approximating chi-square distribution is equal to the difference in the number of regression coefficients in the two models. The test is named as a ratio rather than a difference since the difference between two log likelihoods is equal to the log of the ratio of the two likelihoods.

Research paper thumbnail of Matched analysis for paired binary data (McNemar test)

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Survival analysis, part 2: Kaplan-Meier method and the log-rank test

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Survival analysis, part 1: Introduction

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of Introduction to incidence rates and time-changing variables for cohort studies

American Journal of Orthodontics and Dentofacial Orthopedics, 2017

Research paper thumbnail of The use of tailored subheadings was successful in enhancing compliance with CONSORT in a dental journal

Journal of Dentistry, 2017

Objectives: Efforts to enhance the reporting of clinical trials have intensified in recent years ... more Objectives: Efforts to enhance the reporting of clinical trials have intensified in recent years with automated strategies and editorial involvement showing promise in improving compliance with accepted guidelines. This study aimed to evaluate the effectiveness of a concerted approach to adherence to CONSORT (CONsolidated Standards Of Reporting Trials) guidelines in a dental journal. Materials and Methods: Following the publication of an exemplar clinical trial on the American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO) website and related changes to the author guidelines, trial submissions were required to follow a standard format incorporating subheadings mirroring the CONSORT guidelines. Compliance with CONSORT was assessed in initial submissions over a 30-month period. Reporting was compared to submissions of randomized controlled trials (RCTs) which did not include subheadings over the same period. Results: Seventy-one RCTs were submitted to the AJO-DO from January 2014 to June 2016, 49 with subheadings and 22 without. Most CONSORT items (e.g. random sequence generation, allocation concealment and blinding) were more frequently adequately reported when RCTs were submitted with inclusion of subheadings. Overall, reporting quality of the submitted RCTs was 15.2% higher with use of the subheadings format (95%CI: 10.5, 20.0; p<0.001) with a mean overall score of 87.3%. Conclusion: Enhanced compliance of submitted RCTs was found with use of a bespoke approach to trial presentation utilizing CONSORT item subheadings. The improvement in initial submissions is particularly encouraging as this arose without input either from peer reviewers or journal editors. This simple approach may have wider applicability.

Research paper thumbnail of The evidence from systematic reviews and meta-analyses published in orthodontic literature. Where do we stand?

European journal of orthodontics, Jan 8, 2015

Summary AIM : To analyse meta-analyses included in systematic reviews (SRs) published in leading ... more Summary AIM : To analyse meta-analyses included in systematic reviews (SRs) published in leading orthodontic journals and the Cochrane Database of Systematic Reviews (CDSR) focusing on orthodontic literature and to assess the quality of the existing evidence. Electronic searching was undertaken to identify SRs published in five major orthodontic journals and the CDSR between January 2000 and June 2014. Quality assessment of the overall body of evidence from meta-analyses was conducted using the Grading of Recommendations Assessment, Development and Evaluation working group (GRADE) tool. One hundred and fifty-seven SRs were identified; meta-analysis was present in 43 of these (27.4 per cent). The highest proportion of SRs that included a meta-analysis was found in Orthodontics and Craniofacial Research (6/13; 46.1 per cent), followed by the CDSR (12/33; 36.4 per cent) and the American Journal of Orthodontics and Dentofacial Orthopaedics (15/44; 34.1 per cent). Class II treatment was ...

Research paper thumbnail of Statistical testing against baseline was common in dental research

Journal of clinical epidemiology, Jan 12, 2015

To assess the presence of within-group comparisons with baseline in a subset of leading dental jo... more To assess the presence of within-group comparisons with baseline in a subset of leading dental journals and to explore possible associations with a range of study characteristics including journal and study design. Thirty consecutive issues of five leading dental journals were electronically searched. The conduct and reporting of statistical analysis in respect of comparisons against baseline or otherwise along with the manner of interpretation of the results were assessed. Descriptive statistics were obtained, and chi-square test and Fisher's exact were undertaken to test the association between trial characteristics and overall study interpretation. A total of 184 studies were included with the highest proportion published in Journal of Endodontics (n = 84, 46%) and most involving a single center (n = 157, 85%). Overall, 43 studies (23%) presented interpretation of their outcomes based solely on comparisons against baseline. Inappropriate use of baseline testing was found to b...

Research paper thumbnail of Blinded by PRISMA: Are Systematic Reviewers Focusing on PRISMA and Ignoring Other Guidelines?

PLoS ONE, 2014

Background: PRISMA guidelines have been developed to improve the reporting of systematic reviews ... more Background: PRISMA guidelines have been developed to improve the reporting of systematic reviews (SRs). Other reporting guidelines and techniques to assess methodological quality of SRs have been developed. We aimed to assess the frequency of the use of reporting and other guidelines in SRs to assess whether PRISMA is being used inappropriately as a substitute for other relevant guidelines. Methods: Web of Knowledge was searched to identify articles citing the PRISMA guidelines over a 12-month period. The use of reporting guidelines (including PRISMA and MOOSE) and tools for assessing methodological quality (including QUADAS) was assessed. Factors associated with appropriate use of guidelines including review type, field of publication and involvement of a methodologist were investigated. Results: Over the 12-month period, 701 SRs were identified. MOOSE guidelines were cited in just 17% of epidemiologic reviews; QUADAS or QUADAS-2 was referred to in just 40% of diagnostic SRs. In the multivariable analysis, medical field of publication and methodologist involvement (OR = 1.97, 95% CI: 1.37, 2.83) were significant predictors of appropriate use of guidelines. Inclusion of a meta-analysis resulted in 73% higher odds of appropriate usage of systematic review guidelines (OR = 1.73, 95% CI: 1.22, 2.35). Conclusions: Usage of SR reporting guidelines and tools for assessment of methodological quality other than PRISMA may be under-utilized with negative implications both for the reporting and methodological quality of systematic reviews.

Research paper thumbnail of Are Sample Sizes Clear and Justified in RCTs Published in Dental Journals?

PLoS ONE, 2014

Sample size calculations are advocated by the CONSORT group to justify sample sizes in randomized... more Sample size calculations are advocated by the CONSORT group to justify sample sizes in randomized controlled trials (RCTs). The aim of this study was primarily to evaluate the reporting of sample size calculations, to establish the accuracy of these calculations in dental RCTs and to explore potential predictors associated with adequate reporting. Electronic searching was undertaken in eight leading specific and general dental journals. Replication of sample size calculations was undertaken where possible. Assumed variances or odds for control and intervention groups were also compared against those observed. The relationship between parameters including journal type, number of authors, trial design, involvement of methodologist, single-/multi-center study and region and year of publication, and the accuracy of sample size reporting was assessed using univariable and multivariable logistic regression. Of 413 RCTs identified, sufficient information to allow replication of sample size calculations was provided in only 121 studies (29.3%). Recalculations demonstrated an overall median overestimation of sample size of 15.2% after provisions for losses to follow-up. There was evidence that journal, methodologist involvement (OR = 1.97, CI: 1.10, 3.53), multi-center settings (OR = 1.86, CI: 1.01, 3.43) and time since publication (OR = 1.24, CI: 1.12, 1.38) were significant predictors of adequate description of sample size assumptions. Among journals JCP had the highest odds of adequately reporting sufficient data to permit sample size recalculation, followed by AJODO and JDR, with 61% (OR = 0.39, CI: 0.19, 0.80) and 66% (OR = 0.34, CI: 0.15, 0.75) lower odds, respectively. Both assumed variances and odds were found to underestimate the observed values. Presentation of sample size calculations in the dental literature is suboptimal; incorrect assumptions may have a bearing on the power of RCTs.

Research paper thumbnail of Mislabeling Controlled Clinical Trials (CCTs) as “Randomized Clinical Trials (RCTs)” in Dental Specialty Journals

Journal of Evidence Based Dental Practice, 2012

Objectives: This study aimed to investigate whether studies published in dental journals with the... more Objectives: This study aimed to investigate whether studies published in dental journals with the highest impact factor, representing the 5 major dental specialties and titled as randomized clinical trials (RCTs) are truly RCTs. A second objective was to explore the association of journal type and other publication characteristics on correct classification. Methods: The American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), the British Journal of Oral and Maxillofacial Surgery (BJOMS), the International Journal of Prosthodontics (IJP), the Journal of Clinical Periodontology (JCP), and the Journal of Endodontics (JOE) were hand searched for clinical trials labeled in the title as randomized from 1979 to July 2011. The data were analyzed using descriptive statistics, and univariable and multivariable examination of statistical associations via ordinal logistic regression modeling (proportional odds model). Results: A total of 222 trials were identified. From the included trials, 88 (39.64%) were considered to be RCTs, 107 (48.20%) were considered to be of unclear status, and 27 (12.16%) were not considered as RCTs. In the multivariable analysis among the included variables, journal type, involvement of statistician, year of publication, multicenter trial, and number of authors were significant predictors of correctly classifying a study as an RCT versus no RCT and of unclear status. Conclusions: This study indicates the need for clear and accurate reporting of clinical trials and the need for educating investigators on RCT methodology.