scholarly journals Assessing the risk of bias in randomized controlled trials in the field of dentistry indexed in the Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) database

2011 ◽  
Vol 129 (2) ◽  
pp. 85-93 ◽  
Author(s):  
Christiane Alves Ferreira ◽  
Carlos Alfredo Salles Loureiro ◽  
Humberto Saconato ◽  
Álvaro Nagib Atallah
Keyword(s):  
Randomized Controlled Trials ◽  
Research Question ◽  
Allocation Concealment ◽  
Risk Of Bias ◽  
Low Risk ◽  
Controlled Trials ◽  
Level Of Evidence ◽  
Randomized Controlled ◽  
Decision Making Processes ◽  
Meta Analyses

CONTEXT AND OBJECTIVE: Well-conducted randomized controlled trials (RCTs) represent the highest level of evidence when the research question relates to the effect of therapeutic or preventive interventions. However, the degree of control over bias between RCTs presents great variability between studies. For this reason, with the increasing interest in and production of systematic reviews and meta-analyses, it has been necessary to develop methodology supported by empirical evidence, so as to encourage and enhance the production of valid RCTs with low risk of bias. The aim here was to conduct a methodological analysis within the field of dentistry, regarding the risk of bias in open-access RCTs available in the Lilacs (Literatura Latino-Americana e do Caribe em Ciências da Saúde) database. DESIGN AND SETTING: This was a methodology study conducted at Universidade Federal de São Paulo (Unifesp) that assessed the risk of bias in RCTs, using the following dimensions: allocation sequence generation, allocation concealment, blinding, and data on incomplete outcomes. RESULTS: Out of the 4,503 articles classified, only 10 studies (0.22%) were considered to be true RCTs and, of these, only a single study was classified as presenting low risk of bias. The items that the authors of these RCTs most frequently controlled for were blinding and data on incomplete outcomes. CONCLUSION: The effective presence of bias seriously weakened the reliability of the results from the dental studies evaluated, such that they would be of little use for clinicians and administrators as support for decision-making processes.

scholarly journals Randomized Controlled Trials on Complementary and Traditional Medicine in the Korean Literature

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Chang-Kyu Kim ◽  
Da-Hee Kim ◽  
Myeong Soo Lee ◽  
Jong-In Kim ◽  
L. Susan Wieland ◽  
...  
Keyword(s):  
Randomized Controlled Trials ◽  
Traditional Medicine ◽  
Systematic Reviews ◽  
Allocation Concealment ◽  
Risk Of Bias ◽  
Controlled Trials ◽  
Korean Literature ◽  
Language Bias ◽  
Randomized Controlled ◽  
Study Characteristics

Objective. This study aimed to identify all of the features of complementary and alternative (CAM) randomized controlled trials (RCTs) in the Korean literature and then introduce English-speaking researchers to the bibliometric and risk of bias characteristics of this literature.Methods. Eleven electronic databases and sixteen Korean journals were searched to August 2013 for RCTs of CAM therapies. Key study characteristics were extracted and risk of bias was assessed using the Cochrane Collaboration’s tool for assessing risk of bias.Results. Three hundred and sixty publications met our inclusion criteria. Complementary and traditional medicine RCTs in the Korean literature emerged in the mid-1990s and increased in the mid-2000s. The most common CAM interventions include acupuncture (59.4%) and herbal medicine (8.3%). The largest proportion of trials evaluated CAM for musculoskeletal conditions (20.7%). Adequate methods of randomization were reported in 41.7% of the RCTs, whereas only 8.3% reported adequate allocation concealment. A low proportion of trials reported participant blinding (34.2%) and outcome assessor blinding (22.5%).Conclusions. Korean CAM RCTs are typically omitted from systematic reviews resulting in the potential for language bias. This study will enable these trials of diverse quality to be identified and assessed for inclusion in future systematic reviews on CAM interventions.

scholarly journals Impact of risk of bias on the magnitude of treatment effects of randomized controlled trials in implant dentistry

2020 ◽  
Author(s):  
Ruolin Ding ◽  
Wenxin Lu ◽  
Jianru Yi ◽  
Liang Zhang ◽  
Zhihe Zhao
Keyword(s):  
Randomized Controlled Trials ◽  
Treatment Effects ◽  
Permutation Test ◽  
Random Sequence ◽  
Allocation Concealment ◽  
Risk Of Bias ◽  
Selective Reporting ◽  
Controlled Trials ◽  
Randomized Controlled ◽  
Implant Dentistry

Abstract Background: Risk of bias (RoB) could influence the magnitude of treatment effects of randomized controlled trials (RCTs). This study aims to investigate the potential influence of RoB on treatment effects estimates in RCTs in implant dentistry. Methods: The RCTs published in five leading oral implant journals during the recent five years were electronically searched. The RoB was assessed using the Cochrane Collaboration RoB tool. The meta-regression analysis and Monte Carlo permutation test were performed to identify the association between RoB and the magnitude of treatment effects.Results: A considerable amount of studies have high RoB in blinding of participants and personnel, and unclear RoB in allocation concealment and selective reporting. The treatment effects were exaggerated by flaws in allocation concealment for binary outcomes and by deficiencies in random sequence generation and selective reporting for continuous outcomes.Conclusion: RoB frequently exists in RCTs recently published in implant dentistry, which may lead to the exaggeration of treatment effects. Better study design, implementation, and reporting are required for clinical trials in implant dentistry to ensure more reliable evidence.

scholarly journals Pharmacological Prevention of Postoperative Delirium: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yong Liu ◽  
Xiao-Jin Li ◽  
Yi Liang ◽  
Yan Kang
Keyword(s):  
Beneficial Effect ◽  
Randomized Controlled Trials ◽  
Methodological Quality ◽  
Postoperative Delirium ◽  
Risk Of Bias ◽  
Low Risk ◽  
Sufficient Evidence ◽  
Controlled Trials ◽  
Randomized Controlled ◽  
Pharmacological Prevention

Background. The high prevalence of delirium among postoperative patients has increased morbidity and mortality. The kind of drug that can effectively reduce the incidence of delirium has become the focus of discussion in recent years. However, a consensus in this respect has yet to be reached. Methods. Randomized controlled trials (RCTs) were retrieved from the PubMed, Cochrane Library, ClinicalTrials.gov, and Embase databases from their inception through October 12, 2018. We included RCTs of pharmacological prevention for postoperative delirium in adults (at least 18 years), and the Cochrane risk of bias tool was used to evaluate the methodological quality of trials. The primary outcomes were the risk ratios (RRs) of incidence of postoperative delirium, and the secondary outcomes were the RRs of mortality and adverse events in the intervention and control groups. Results. Thirty-eight trials, which comprised 20302 patients and 18 different drugs, were included in the analysis. Of the 38 studies, 17 were rated as low risk with respect to methodological quality. Dexmedetomidine administration (RR 0.58, 95%CI 0.44-0.76, P<0.01) was associated with a significantly lower incidence of postoperative delirium than the control conditions. However, the findings from the studies with a low risk of bias did not show a significant difference in this beneficial effect (RR 0.64, 95%CI 0.39-1.04, P=0.07). The antipsychotic drugs olanzapine (RR 0.44, 95%CI 0.30- 0.65, P<0.01) and risperidone (RR 0.42, 95%CI 0.19-0.92, P=0.03) had promising effects, but there was a lack of sufficient evidence to obtain a definitive conclusion. The beneficial effect of other drugs, including haloperidol, methylprednisolone, dexamethasone, gabapentin, ketamine, cyproheptadine, donepezil, hypertonic saline, melatonin, nimodipine, ondansetron, pregabalin, rivastigmine, TJ-54, and tryptophan, was not proven on the basis of present evidence. Conclusion. Among the pharmacological prophylactic measures for postoperative delirium, dexmedetomidine, olanzapine, and risperidone showed higher efficacy than other drugs. However, more high-quality evidence is needed to confirm these results.

Outcomes of Surgical Treatment of Migraines: A Systematic Review & Meta-Analysis

2021 ◽  
pp. 229255032110367
Author(s):  
Adam G. Evans ◽  
Dorian S. Hill ◽  
Andrew E. Grush ◽  
Mauricio A. Downer ◽  
Maryo M. Ibrahim ◽  
...  
Keyword(s):  
Systematic Review ◽  
Randomized Controlled Trials ◽  
Migraine Headache ◽  
Risk Of Bias ◽  
Controlled Trials ◽  
Headache Frequency ◽  
Randomized Controlled ◽  
Headache Severity ◽  
Meta Analyses ◽  
Migraine Surgery

Background: Migraine surgery at 1 of 6 identified “trigger sites” of a target cranial sensory nerve has rapidly grown in popularity since 2000. This study summarizes the effect of migraine surgery on headache severity, headache frequency, and the migraine headache index score which is derived by multiplying migraine severity, frequency, and duration. Materials and Methods: This is a PRISMA-compliant systematic review of 5 databases searched from inception through May 2020 and is registered under the PROSPERO ID: CRD42020197085. Clinical trials treating headaches with surgery were included. Risk of bias was assessed in randomized controlled trials. Meta-analyses were performed on outcomes using a random effects model to determine the pooled mean change from baseline and when possible, to compare treatment to control. Results: 18 studies met criteria including 6 randomized controlled trials, 1 controlled clinical trial, and 11 uncontrolled clinical trials treated 1143 patients with pathologies including migraine, occipital migraine, frontal migraine, occipital nerve triggered headache, frontal headache, occipital neuralgia, and cervicogenic headache. Migraine surgery reduced headache frequency at 1 year postoperative by 13.0 days per month as compared to baseline ( I2 = 0%), reduced headache severity at 8 weeks to 5 years postoperative by 4.16 points on a 0 to 10 scale as compared to baseline ( I2 = 53%), and reduced migraine headache index at 1 to 5 years postoperative by 83.1 points as compared to baseline ( I2 = 2%). These meta-analyses are limited by a small number of studies that could be analyzed, including studies with high risk of bias. Conclusion: Migraine surgery provided a clinically and statistically significant reduction in headache frequency, severity, and migraine headache index scores. Additional studies, including randomized controlled trials with low risk-of-bias should be performed to improve the precision of the outcome improvements.

scholarly journals Covered versus bare stents for transjugular intrahepatic portosystemic shunt: an updated meta-analysis of randomized controlled trials

2016 ◽  
Vol 10 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Xingshun Qi ◽  
Yulong Tian ◽  
Wei Zhang ◽  
Zhiping Yang ◽  
Xiaozhong Guo
Keyword(s):  
Overall Survival ◽  
Randomized Controlled Trials ◽  
Meta Analysis ◽  
Portosystemic Shunt ◽  
Risk Of Bias ◽  
Controlled Trials ◽  
Covered Stents ◽  
Randomized Controlled ◽  
Intrahepatic Portosystemic Shunt ◽  
Meta Analyses

Background: Transjugular intrahepatic portosystemic shunt (TIPS) is a standard treatment option for the management of portal hypertension in liver cirrhosis. Since the introduction of covered stents, shunt patency has been greatly improved. However, it remains uncertain about whether covered stents could improve survival. A meta-analysis of randomized controlled trials has been performed to compare the outcomes of covered versus bare stents for TIPS. Methods: PubMed, EMBASE, and Cochrane Library databases were searched to identify the relevant randomized controlled trials. Overall survival, shunt patency, and hepatic encephalopathy were the major endpoints. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated. Heterogeneity was calculated. Cochrane risk of bias tool was employed. Results: Overall, 119 papers were identified. Among them, four randomized controlled trials were eligible. Viatorr covered stents alone, Fluency covered stents alone, and Viatorr plus Fluency covered stents were employed in one, two, and one randomized controlled trials, respectively. Risk of bias was relatively low. Meta-analyses demonstrated that the covered-stents group had significantly higher probabilities of overall survival (HR = 0.67, 95% CI = 0.50–0.90, p = 0.008) and shunt patency (HR = 0.42, 95% CI = 0.29–0.62, p < 0.0001) than the bare-stents group. Additionally, the covered-stents group might have a lower risk of hepatic encephalopathy than the bare-stents group (HR = 0.70, 95% CI = 0.49–1.00, p = 0.05). The heterogeneity among studies was not statistically significant in the meta-analyses. Conclusions: Compared with bare stents, covered stents for TIPS may improve the overall survival. In the era of covered stents, the indications for TIPS may be further expanded.

Impact of Selection Bias on Treatment Effect Size Estimates in Randomized Trials of Oral Health Interventions: A Meta-epidemiological Study

2017 ◽  
Vol 97 (1) ◽  
pp. 5-13 ◽  
Author(s):  
H. Saltaji ◽  
S. Armijo-Olivo ◽  
G.G. Cummings ◽  
M. Amin ◽  
B.R. da Costa ◽  
...  
Keyword(s):  
Oral Health ◽  
Randomized Controlled Trials ◽  
Selection Bias ◽  
Allocation Concealment ◽  
Controlled Trials ◽  
Sequence Generation ◽  
Randomized Controlled ◽  
Treatment Effect Size ◽  
Meta Analyses ◽  
Unknown Sequence

Emerging evidence suggests that design flaws of randomized controlled trials can result in over- or underestimation of the treatment effect size (ES). The objective of this study was to examine associations between treatment ES estimates and adequacy of sequence generation, allocation concealment, and baseline comparability among a sample of oral health randomized controlled trials. For our analysis, we selected all meta-analyses that included a minimum of 5 oral health randomized controlled trials and used continuous outcomes. We extracted data, in duplicate, related to items of selection bias (sequence generation, allocation concealment, and baseline comparability) in the Cochrane Risk of Bias tool. Using a 2-level meta-meta-analytic approach with a random effects model to allow for intra- and inter-meta-analysis heterogeneity, we quantified the impact of selection bias on the magnitude of ES estimates. We identified 64 meta-analyses, including 540 randomized controlled trials analyzing 137,957 patients. Sequence generation was judged to be adequate (at low risk of bias) in 32% ( n = 173) of trials, and baseline comparability was judged to be adequate in 77.8% of trials. Allocation concealment was unclear in the majority of trials ( n = 458, 84.8%). We identified significantly larger treatment ES estimates in trials that had inadequate/unknown sequence generation (difference in ES = 0.13; 95% CI: 0.01 to 0.25) and inadequate/unknown allocation concealment (difference in ES = 0.15; 95% CI: 0.02 to 0.27). In contrast, baseline imbalance (difference in ES = 0.01, 95% CI: –0.09 to 0.12) was not associated with inflated or underestimated ES. In conclusion, treatment ES estimates were 0.13 and 0.15 larger in trials with inadequate/unknown sequence generation and inadequate/unknown allocation concealment, respectively. Therefore, authors of systematic reviews using oral health randomized controlled trials should perform sensitivity analyses based on the adequacy of sequence generation and allocation concealment.

scholarly journals Pre-Procedural Lumbar Neuraxial Ultrasound—A Systematic Review of Randomized Controlled Trials and Meta-Analysis

Healthcare ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 479
Author(s):  
Tatiana Sidiropoulou ◽  
Kalliopi Christodoulaki ◽  
Charalampos Siristatidis
Keyword(s):  
Systematic Review ◽  
Lumbar Spine ◽  
Randomized Controlled Trials ◽  
Success Rate ◽  
Meta Analysis ◽  
Controlled Trials ◽  
Technical Failure ◽  
Obese Patients ◽  
Randomized Controlled ◽  
Meta Analyses

A pre-procedural ultrasound of the lumbar spine is frequently used to facilitate neuraxial procedures. The aim of this review is to examine the evidence sustaining the utilization of pre-procedural neuraxial ultrasound compared to conventional methods. We perform a systematic review of randomized controlled trials with meta-analyses. We search the electronic databases Medline, Cochrane Central, Science Direct and Scopus up to 1 June 2019. We include trials comparing a pre-procedural lumbar spine ultrasound to a non-ultrasound-assisted method. The primary endpoints are technical failure rate, first-attempt success rate, number of needle redirections and procedure time. We retrieve 32 trials (3439 patients) comparing pre-procedural lumbar ultrasounds to palpations for neuraxial procedures in various clinical settings. Pre-procedural ultrasounds decrease the overall risk of technical failure (Risk Ratio (RR) 0.69 (99% CI, 0.43 to 1.10), p = 0.04) but not in obese and difficult spinal patients (RR 0.53, p = 0.06) and increase the first-attempt success rate (RR 1.5 (99% CI, 1.22 to 1.86), p < 0.0001, NNT = 5). In difficult spines and obese patients, the RR is 1.84 (99% CI, 1.44 to 2.3; p < 0.0001, NNT = 3). The number of needle redirections is lower with pre-procedural ultrasounds (SMD = −0.55 (99% CI, −0.81 to −0.29), p < 0.0001), as is the case in difficult spines and obese patients (SMD = −0.85 (99% CI, −1.08 to −0.61), p < 0.0001). No differences are observed in procedural times. Ιn conclusion, a pre-procedural ultrasound provides significant benefit in terms of technical failure, number of needle redirections and first attempt-success rate. Τhe effect of pre-procedural ultrasound scanning of the lumbar spine is more significant in a subgroup analysis of difficult spines and obese patients.

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