P-OGC97 Development and piloting of surgical quality assurance methods for randomised controlled trials (RCTs): an example from a trial comparing laparoscopically assisted oesophagectomy vs. open oesophagectomy

Background RCTs in surgery are frequently criticised because the standard to which operations are performed (quality assurance - QA) is not considered during study design and delivery, risking performance bias. Lack of clarity about surgical QA may also influence the successful implementation of RCT results into routine practice, because it is unclear how procedures were undertaken. We developed QA measures for an RCT comparing laparoscopically assisted and open oesophagectomy (LAO and OO). Methods Five QA categories were developed during the pilot and applied to the main trial, using data from patients receiving their randomized allocation in each group: i) entry criteria for centres; ii) entry criteria for surgeons; surgical protocols for key components of LAO and OO with mandated, prohibited and flexible components, monitored using iii) case report forms (CRFs) to record protocol adherence; and iv) intra-operative photographs to demonstrate protocol adherence (using the visible anatomical structures to determine if the component had been fully completed); and v) lymph node count and length of oesophagus. Results 8 centres and 39 surgeons participated and met entry criteria. 145 (LAO) and 149 (OO) patients underwent their randomized surgical procedure. Key procedural components were reported as complete in CRFs at similar rates in both groups, with >70% undergoing mandated components. However, adherence assessed using photographs was consistently lower than the CRFs. For example, left gastric artery lymphadenectomies were reported as complete in > 98% CRFs (LAO and OO) whereas photographs found this to be complete in 42% (OO) and 54% (LAO). Median nodal count was similar in both groups (145 LAO=24.7, SD = 10.6 and 149 OO = 26.4, SD = 10.2) as was length of resected oesophagus. Conclusions Assessing surgical QA in a multi-centre trial is logistically challenging but feasible. Whilst video data from laparoscopic cases could be collected and assessed, it was not possible with open surgery. Understanding adherence to the study protocol using photographs in addition to CRFs was important because of marked differences between what surgeons reported had been undertaken and images of what had been achieved. It is recommended that surgical trials include QA processes to understand protocol adherence and examine performance bias between groups.

Remote Medical Scent Detection of Cancer and Infectious Diseases With Dogs and Rats: a Systematic Review

Background: Remote medical scent detection of cancer and infectious diseases with dogs and rats has been an increasing field of research these last 20 years. If validated, the possibility of implementing such a technique in the clinic raises many hopes. This systematic review was performed to determine the evidence and performance of such methods and assess their potential relevance in the clinic.Methods: Pubmed and Web of Science databases were independently searched based on PRISMA standards. We included studies aiming at detecting cancers and infectious diseases affecting humans with dogs or rats. We excluded studies using other animals, studies aiming to detect agricultural diseases, diseases affecting animals, and others such as diabetes and neurodegenerative diseases. Only original articles were included. Data about patients’ selection, samples, animal characteristics, animal training and testing configurations, and performances were recorded.Results: A total of 62 studies were included. Sensitivity and specificity varied a lot among studies: While some publications report low sensitivities of 17% and specificities around 29%, others achieve rates of 100% sensitivity and specificity. Only 6 studies were evaluated in a double-blind screening like situation. In general, the risk of performance bias was high in most evaluated studies, and the quality of the evidence found was low.Conclusions: Medical detection using animals’ sense of smell lacks evidence and performances so far to be applied in the clinic. What odours the animals detect is not well understood. Further research should be conducted, focusing on patient selection, samples (choice of materials, standardization), and testing conditions. Interpolations of such results to free running detection (direct contact with humans) should be taken with extreme caution.

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

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.

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

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.

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

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.

Reversing the Luminance Polarity of Control Faces: Why Are Some Negative Faces Harder to Recognize, but Easier to See?

Control stimuli are key for understanding the extent to which face processing relies on holistic processing, and affective evaluation versus the encoding of low-level image properties. Luminance polarity (LP) reversal combined with face inversion is a popular tool for severely disrupting the recognition of face controls. However, recent findings demonstrate visibility-recognition trade-offs for LP-reversed faces, where these face controls sometimes appear more salient despite being harder to recognize. The present report brings together findings from image analysis, simple stimuli, and behavioral data for facial recognition and visibility, in an attempt to disentangle instances where LP-reversed control faces are associated with a performance bias in terms of their perceived salience. These findings have important implications for studies of subjective face appearance, and highlight that future research must be aware of behavioral artifacts due to the possibility of trade-off effects.

Quality assessment of studies included in Cochrane oral health systematic reviews

ObjectivesThe 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.