scholarly journals Quality Assessment of Clinical Trials Included in Cochrane Oral Health Systematic Reviews

2021 ◽  
Author(s):  
Ahmad Sofi-Mahmudi ◽  
Pouria Iranparvar ◽  
Maryam Shakiba ◽  
Erfan Shamsoddin ◽  
Hossein Mohammad-Rahimi ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Oral Health ◽  
High Risk ◽  
Systematic Reviews ◽  
Cochrane Review ◽  
Risk Of Bias ◽  
Double Blind ◽  
Cochrane Reviews ◽  
Health Studies ◽  
Performance Bias

Abstract Background: Risk of Bias (RoB) and other characteristics of randomised clinical trials included in Cochrane oral health systematic reviews were assessed.Methods: All the trials included in Cochrane oral health systematic reviews were identified and examined. The RoB was evaluated for all the included clinical trials according to the Cochrane review standards. The Overall Risk of Bias (ORoB) was defined in this study based on the criteria in Cochrane’s RoB tool-v2. Descriptive analyses were carried out to determine the frequency of each intended variable.Results: In a total of 2565 included studies, the majority (n=1600) had 50 or higher sample sizes. As for blinding, 907 studies were labelled as double-blind. Performance bias showed the highest rate of high risk (31.4%). Almost half of the studies had a high ORoB compared to 11.1% with low ORoB. The studies that used placebos had higher low ORoB (14.8% vs 10.7%). The double-blind studies had the highest low ORoB (23.6%). The studies with a cross-over design had the highest low ORoB (28.8%).Conclusion: The RoB of oral health studies in Cochrane reviews was deemed high. Special efforts may be required to improve conducting and reporting of trials in this area.

scholarly journals Quality assessment of studies included in Cochrane oral health systematic reviews

2020 ◽  
Author(s):  
Ahmad Sofi-Mahmudi ◽  
Pouria Iranparvar ◽  
Maryam Shakiba ◽  
Erfan Shamsoddin ◽  
Hossein Mohammad-Rahimi ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Oral Health ◽  
High Risk ◽  
Systematic Reviews ◽  
Randomized Clinical Trials ◽  
Cochrane Review ◽  
Risk Of Bias ◽  
Double Blind ◽  
Cochrane Reviews ◽  
Performance Bias

AbstractObjectivesThe Risk of Bias (RoB) and other characteristics of randomized clinical trials included in Cochrane oral health systematic reviews were assessed.Study Design and SettingsAll the trials included in Cochrane oral health systematic reviews were examined. The RoB was evaluated for all the included clinical trials according to the Cochrane review standards. The Overall Risk of Bias (ORoB) was defined in this study based on the criteria for determining the overall bias in Cochrane’s RoB tool-v2. Descriptive analyses were carried out to determine the frequency of each intended variable.ResultsA total of 2565 studies were included in our analysis. The majority of the studies (n=1600) had sample sizes of 50 or higher. As for blinding, 907 studies were labelled as double-blind. Performance bias showed the highest rate of high risk (31.4%). Almost half of the studies had a high ORoB compared to 11.1% with low ORoB. The studies that used placebos had higher low ORoB (14.8% vs. 10.7%). The double-blind studies had the highest low ORoB (23.6%). The studies with a cross-over design had the highest low ORoB (28.8%).ConclusionOverall, the RoB for the studies on dentistry and oral health in Cochrane reviews was deemed high.

scholarly journals Quality Assessment of Studies Included in Cochrane Oral Health Systematic Reviews: A Meta-Research

2021 ◽  
Vol 18 (14) ◽  
pp. 7284
Author(s):  
Ahmad Sofi-Mahmudi ◽  
Pouria Iranparvar ◽  
Maryam Shakiba ◽  
Erfan Shamsoddin ◽  
Hossein Mohammad-Rahimi ◽  
...  
Keyword(s):  
Clinical Trials ◽  
Oral Health ◽  
Systematic Reviews ◽  
Cochrane Review ◽  
Crossover Design ◽  
Risk Of Bias ◽  
Double Blind ◽  
Cochrane Reviews ◽  
Health Studies ◽  
Performance Bias

Objectives: To assess the Risk of Bias (RoB) and other characteristics of published randomised clinical trials within Cochrane oral health systematic reviews. Materials and methods: All the published clinical trials within Cochrane oral health systematic reviews until June 1, 2020 were identified and examined. RoB was assessed for all the included clinical trials according to the Cochrane review standards. The Overall Risk of Bias (ORoB) was defined in this study using Cochrane’s RoB tool-v2. Descriptive analyses were carried out to determine the frequency of each variable in the study sample. Results: Out of a total of 2565 included studies, the majority (n = 1600) had sample sizes of 50 or higher. Regarding blinding, 907 studies were labelled as double-blind. Among the various domains of bias, the performance bias showed the highest rate of high risk (31.4%). Almost half of the studies had a high ORoB, compared to 11.1% with a low ORoB. The studies that used placebos had a higher percentage of low ORoB (14.8% vs. 10.7%). Additionally, the double- and triple-blind studies had higher percentages of low ORoB (23.6% and 23.3%, respectively), while the studies with a crossover design had the highest percentage of low ORoB (28.8%). Conclusion: The RoB of oral health studies published as Cochrane reviews was deemed high.

scholarly journals Assessing the risk of performance and detection bias in Cochrane reviews as a joint domain is less accurate compared to two separate domains

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ognjen Barcot ◽  
Matija Boric ◽  
Svjetlana Dosenovic ◽  
Livia Puljak
Keyword(s):  
High Risk ◽  
Risk Of Bias ◽  
Low Risk ◽  
Single Domain ◽  
Similar Proportion ◽  
Detection Bias ◽  
Cochrane Reviews ◽  
Outcome Type ◽  
Performance Bias ◽  
Made In

Abstract Background Initially, the Cochrane risk of bias (RoB) tool had a domain for “blinding of participants, personnel and outcome assessors”. In the 2011 tool, the assessment of blinding was split into two domains: blinding of participants and personnel (performance bias) and blinding of outcome assessors (detection bias). The aims of this study were twofold; first, to analyze the frequency of usage of the joint blinding domain (a single domain for performance and detection bias), and second, to assess the proportion of adequate assessments made in the joint versus single RoB domains for blinding by comparing whether authors’ RoB judgments were supported by explanatory comments in line with the Cochrane Handbook recommendations. Methods We extracted information about the assessment of blinding from RoB tables (judgment, comment, and whether it was specified which outcome type; e.g., objective, subjective) of 729 Cochrane reviews published in 2015-2016. In the Cochrane RoB tool, judgment (low, unclear or high risk) needs to be accompanied by a transparent comment, in which authors provide a summary justifying RoB judgment, to ensure transparency in how these judgments were reached. We reassessed RoB based on the supporting comments reported in Cochrane RoB tables, in line with instructions from the Cochrane Handbook. Then, we compared our new assessments to judgments made by Cochrane authors. We compared the frequency of adequate judgments in reviews with two separate domains for blinding versus those with a joint domain for blinding. Results The total number of assessments for performance bias was 6918, with 8656 for detection bias and 3169 for the joint domain. The frequency of adequate assessments was 74% for performance bias, 78% for detection bias, and 59% for the joint domain. The lowest frequency of adequate assessments was found when Cochrane authors judged low risk – 47% in performance bias, 62% in detection bias, and 31% in the joint domain. The joint domain and detection bias domain had a similar proportion of specified outcome types (17% and 18%, respectively). Conclusions Splitting joint RoB assessment about blinding into two domains was justified because the frequency of adequate judgments was higher in separate domains. Specification of outcome types in RoB domains should be further scrutinized.

scholarly journals Assessing bias in osteoarthritis trials included in Cochrane reviews: protocol for a meta-epidemiological study

BMJ Open ◽  
2014 ◽  
Vol 4 (10) ◽  
pp. e005491 ◽  
Author(s):  
Julie B Hansen ◽  
Carsten B Juhl ◽  
Isabelle Boutron ◽  
Peter Tugwell ◽  
Elizabeth A T Ghogomu ◽  
...  
Keyword(s):  
Systematic Reviews ◽  
Treatment Effect ◽  
Methodological Quality ◽  
Cochrane Review ◽  
Risk Of Bias ◽  
Primary Data ◽  
Forest Plot ◽  
Mean Values ◽  
Cochrane Reviews ◽  
Meta Analyses

IntroductionThe validity of systematic reviews and meta-analysis depends on methodological quality and unbiased dissemination of trials. Our objective is to evaluate the association of estimates of treatment effects with different bias-related study characteristics in meta-analyses of interventions used for treating pain in osteoarthritis (OA). From the findings, we hope to consolidate guidance on interpreting OA trials in systematic reviews based on empirical evidence from Cochrane reviews.Methods and analysisOnly systematic reviews that compare experimental interventions with sham, placebo or no intervention control will be considered eligible. Bias will be assessed with the risk of bias tool, used according to the Cochrane Collaboration’s recommendations. Furthermore, center status, trial size and funding will be assessed. The primary outcome (pain) will be abstracted from the first appearing forest plot for overall pain in the Cochrane review. Treatment effect sizes will be expressed as standardised mean differences (SMDs), where the difference in mean values available from the forest plots is divided by the pooled SD. To empirically assess the risk of bias in treatment benefits, we will perform stratified analyses of the trials from the included meta-analyses and assess the interaction between trial characteristics and treatment effect. A relevant study-level covariate is defined as one that decreases the between-study variance (τ2, estimated as Tau-squared) as a consequence of inclusion in the mixed effects statistical model.Ethics and disseminationMeta-analyses and randomised controlled trials provide the most reliable basis for treatment of patients with OA, but the actual impact of bias is unclear. This study will systematically examine the methodological quality in OA Cochrane reviews and explore the effect estimates behind possible bias. Since our study does not collect primary data, no formal ethical assessment and informed consent are required.Trial registration numberPROSPERO (CRD42013006924).

scholarly journals Outcome reporting bias in Cochrane systematic reviews: a cross-sectional analysis

BMJ Open ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. e032497
Author(s):  
Kieran Shah ◽  
Gregory Egan ◽  
Lawrence (Nichoe) Huan ◽  
Jamie Kirkham ◽  
Emma Reid ◽  
...  
Keyword(s):  
Systematic Review ◽  
High Risk ◽  
Systematic Reviews ◽  
Cochrane Review ◽  
Reporting Bias ◽  
Outcome Reporting Bias ◽  
Cross Sectional ◽  
Knowledge Of Results ◽  
Outcome Reporting ◽  
Cochrane Reviews

BackgroundDiscrepancies in outcome reporting (DOR) between protocol and published studies include inclusions of new outcomes, omission of prespecified outcomes, upgrade and downgrade of secondary and primary outcomes, and changes in definitions of prespecified outcomes. DOR can result in outcome reporting bias (ORB) when changes in outcomes occur after knowledge of results. This has potential to overestimate treatment effects and underestimate harms. This can also occur at the level of systematic reviews when changes in outcomes occur after knowledge of results of included studies. The prevalence of DOR and ORB in systematic reviews is unknown in systematic reviews published post-2007.ObjectiveTo estimate the prevalence of DOR and risk of ORB in all Cochrane reviews between the years 2007 and 2014.MethodsA stratified random sampling approach was applied to collect a representative sample of Cochrane systematic reviews from each Cochrane review group. DOR was assessed by matching outcomes in each systematic review with their respective protocol. When DOR occurred, reviews were further assessed if there was a risk of ORB (unclear, low or high risk). We classified DOR as a high risk for ORB if the discrepancy occurred after knowledge of results in the systematic review.Results150 of 350 (43%) review and protocol pairings contained DOR. When reviews were further scrutinised, 23% (35 of 150) of reviews with DOR contained a high risk of ORB, with changes being made after knowledge of results from individual trials.ConclusionsIn our study, we identified just under a half of Cochrane reviews with at least one DOR. Of these, a fifth were at high risk of ORB. The presence of DOR and ORB in Cochrane reviews is of great concern; however, a solution is relatively simple. Authors are encouraged to be transparent where outcomes change and to describe the legitimacy of changing outcomes in order to prevent suspicion of bias.

scholarly journals Trial registration and selective outcome reporting in 585 clinical trials investigating drugs for prevention of postoperative nausea and vomiting

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Manuel Riemer ◽  
Peter Kranke ◽  
Antonia Helf ◽  
Debora Mayer ◽  
Maria Popp ◽  
...  
Keyword(s):  
Clinical Trials ◽  
High Risk ◽  
Postoperative Nausea ◽  
Cochrane Review ◽  
Postoperative Nausea And Vomiting ◽  
Risk Of Bias ◽  
The Body ◽  
Trial Registration ◽  
Selective Outcome Reporting ◽  
Outcome Reporting

Abstract Background Selective outcome reporting in clinical trials introduces bias in the body of evidence distorting clinical decision making. Trial registration aims to prevent this bias and is suggested by the International Committee of Medical Journal Editors (ICMJE) since 2004. Methods The 585 randomized controlled trials (RCTs) published between 1965 and 2017 that were included in a recently published Cochrane review on antiemetic drugs for prevention of postoperative nausea and vomiting were selected. In a retrospective study, we assessed trial registration and selective outcome reporting by comparing study publications with their registered protocols according to the ‘Cochrane Risk of bias’ assessment tool 1.0. Results In the Cochrane review, the first study which referred to a registered trial protocol was published in 2004. Of all 585 trials included in the Cochrane review, 334 RCTs were published in 2004 or later, of which only 22% (75/334) were registered. Among the registered trials, 36% (27/75) were pro- and 64% (48/75) were retrospectively registered. 41% (11/27) of the prospectively registered trials were free of selective outcome reporting bias, 22% (6/27) were incompletely registered and assessed as unclear risk, and 37% (10/27) were assessed as high risk. Major outcome discrepancies between registered and published high risk trials were a change from the registered primary to a published secondary outcome (32%), a new primary outcome (26%), and different outcome assessment times (26%). Among trials with high risk of selective outcome reporting 80% favoured at least one statistically significant result. Registered trials were assessed more often as ‘overall low risk of bias’ compared to non-registered trials (64% vs 28%). Conclusions In 2017, 13 years after the ICMJE declared prospective protocol registration a necessity for reliable clinical studies, the frequency and quality of trial registration in the field of PONV is very poor. Selective outcome reporting reduces trustworthiness in findings of clinical trials. Investigators and clinicians should be aware that only following a properly registered protocol and transparently reporting of predefined outcomes, regardless of the direction and significance of the result, will ultimately strengthen the body of evidence in the field of PONV research in the future.

A Critical Overview of Systematic Reviews of Chemotherapy for Advanced and Locally Advanced Pancreatic Cancer using both AMSTAR2 and ROBIS as Quality Assessment Tools

2020 ◽  
Vol 15 ◽  
Author(s):  
Amit Dang ◽  
Surendar Chidirala ◽  
Prashanth Veeranki ◽  
BN Vallish
Keyword(s):  
Pancreatic Cancer ◽  
High Risk ◽  
Systematic Reviews ◽  
Locally Advanced ◽  
Advanced Pancreatic Cancer ◽  
Risk Of Bias ◽  
Low Risk ◽  
Locally Advanced Pancreatic Cancer ◽  
Grade 3 ◽  
Critical Overview

Background: We performed a critical overview of published systematic reviews (SRs) of chemotherapy for advanced and locally advanced pancreatic cancer, and evaluated their quality using AMSTAR2 and ROBIS tools. Materials and Methods: PubMed and Cochrane Central Library were searched for SRs on 13th June 2020. SRs with metaanalysis which included only randomized controlled trials and that had assessed chemotherapy as one of the treatment arms were included. The outcome measures, which were looked into, were progression-free survival (PFS), overall survival (OS), and adverse events (AEs) of grade 3 or above. Two reviewers independently assessed all the SRs with both ROBIS and AMSTAR2. Results: Out of the 1,879 identified records, 26 SRs were included for the overview. Most SRs had concluded that gemcitabine-based combination regimes, prolonged OS and PFS, but increased the incidence of grade 3-4 toxicities, when compared to gemcitabine monotherapy, but survival benefits were not consistent when gemcitabine was combined with molecular targeted agents. As per ROBIS, 24/26 SRs had high risk of bias, with only 1/26 SR having low risk of bias. As per AMSTAR2, 25/26 SRs had critically low, and 1/26 SR had low, confidence in the results. The study which scored ‘low’ risk of bias in ROBIS scored ‘low confidence in results’ in AMSTAR2. The inter-rater reliability for scoring the overall confidence in the SRs with AMSTAR2 and the overall domain in ROBIS was substantial; ROBIS: kappa=0.785, SEM=0.207, p<0.001; AMSTAR2: kappa=0.649, SEM=0.323, p<0.001. Conclusion: Gemcitabine-based combination regimens can prolong OS and PFS but also worsen AEs when compared to gemcitabine monotherapy. The included SRs have an overall low methodological quality and high risk of bias as per AMSTAR2 and ROBIS respectively.

scholarly journals Is there a role for adjuvant therapy after surgery in “high risk for recurrence” kidney cancer? An update on current concepts

2018 ◽  
Vol 25 (5) ◽  
Author(s):  
T. Sharma ◽  
C. Tajzler ◽  
A. Kapoor
Keyword(s):  
Clinical Trials ◽  
Targeted Therapy ◽  
High Risk ◽  
Adjuvant Therapy ◽  
Patient Population ◽  
Treatment Options ◽  
Significant Proportion ◽  
High Risk Patient ◽  
Disease Free Survival ◽  
Cochrane Reviews

BackgroundAlthough surgical resection remains the standard of care for localized kidney cancers, a significant proportion of patients experience systemic recurrence after surgery and hence might benefit from effective adjuvant therapy. So far, several treatment options have been evaluated in adjuvant clinical trials, but only a few have provided promising results. Nevertheless, with the recent development of targeted therapy and immunomodulatory therapy, a series of clinical trials are in progress to evaluate the potential of those novel agents in the adjuvant setting. In this paper, we provide a narrative review of the progress in this field, and we summarize the results from recent adjuvant trials that have been completed.MethodsA literature search was conducted. The primary search strategy at the medline, Cochrane reviews, and http://ClinicalTrials.gov/ databases included the keywords “adjuvant therapy,” “renal cell carcinoma,” and “targeted therapy or/and immunotherapy.”ConclusionsData from the s-trac study indicated that, in the “highest risk for recurrence” patient population, disease-free survival was increased with the use of adjuvant sunitinib compared with placebo. The assure trial showed no benefit for adjuvant sunitinib or sorafenib in the “intermediate- to high-risk” patient population. The ariser (adjuvant girentuximab) and protect (adjuvant pazopanib) trials indicated no survival benefit, but subgroup analyses in both trials recommended further investigation. The inconsistency in some of the current results can be attributed to a variety of factors pertaining to the lack of standardization across the trials. Nevertheless, patients in the “high risk of recurrence” category after surgery for their disease would benefit from a discussion about the potential benefits of adjuvant treatment and enrolment in ongoing adjuvant trials.

Dexamethasone in Patients with Spontaneous Intracerebral Hemorrhage: An Updated Meta-Analysis

2020 ◽  
Vol 49 (5) ◽  
pp. 495-502
Author(s):  
Stephanie Wintzer ◽  
Josef Georg Heckmann ◽  
Hagen B. Huttner ◽  
Stefan Schwab
Keyword(s):  
Clinical Trials ◽  
High Risk ◽  
Intracerebral Hemorrhage ◽  
Randomized Clinical Trials ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Spontaneous Intracerebral Hemorrhage ◽  
Control Groups ◽  
Language Data ◽  
Negative Effect

<b><i>Background:</i></b> Spontaneous intracerebral hemorrhage (ICH) is a frequent cerebrovascular disorder and still associated with high mortality and poor clinical outcomes. The purpose of this review was to update a 15-year-old former meta-analysis on randomized clinical trials (RCTs) addressing the question of whether ICH patients treated with dexamethasone have better outcomes than controls. <b><i>Methods:</i></b> The electronic databases PubMed, SCOPUS, and Cochrane as well as web platforms on current clinical trials were searched for the years 1970–2020 without constriction on language. Data were extracted and outcomes were pooled for conventional and cumulative meta-analysis using a commercial software program (www.Meta-Analysis.com). <b><i>Results:</i></b> Finally, 7 RCTs were identified and analyzed including 248 participants in the dexamethasone groups and 242 in the control groups. Five studies showed a high risk of bias. The overall relative risk (RR) for death was 1.32 (95% confidence interval [CI] 0.99–1.76; <i>p</i> = 0.06) and did not differ significantly between the 2 groups. After exclusion of studies with high risk of bias, the RR for death was 1.37 (95% CI 0.54–3.42; <i>p</i> = 0.51). The RR for poor outcome did not differ significantly between the 2 groups analyzed for all included studies (RR = 0.69; 95% CI 0.47–1; <i>p</i> = 0.05) and after exclusion of studies with high risk of bias (RR = 0.7; 95% CI 0.45–1.08; <i>p</i> = 0.11). The RR for complications did not differ significantly including all studies (RR = 1.29; 95% CI 0.77–2.17; <i>p</i> = 0.34) and after exclusion of studies with high risk of bias (RR = 1.27; 95% CI 0.18–8.89; <i>p</i> = 0.81). The cumulative statistics delivered no other results; however, it pointed out fewer complications over time in the dexamethasone group. <b><i>Conclusion:</i></b> Clear evidence of a beneficial or negative effect of dexamethasone is still lacking. Modern RCTs or observational studies with propensity design are necessary to evaluate the efficacy and safety of treatment with dexamethasone in patients with ICH.

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