Bastien Perrot

Complete endoscopic sphincterotomy with vs. without large-balloon dilation for the removal of large bile duct stones: randomized multicenter study

Background and study aims Endoscopic sphincterotomy plus large-balloon dilation (ES-LBD) has been reported as an alternative to endoscopic sphincterotomy for the removal of bile duct stones. This multicenter study compared complete endoscopic sphincterotomy with vs. without large-balloon dilation for the removal of large bile duct stones. This is the first randomized multicenter study to evaluate these procedures in patients with exclusively large common bile duct (CBD) stones. Methods Between 2010 and 2015, 150 patients with one or more common bile duct stones ≥ 13 mm were randomized to two groups: 73 without balloon dilation (conventional group), 77 with balloon dilation (ES-LBD group). Mechanical lithotripsy was subsequently performed only if the stones were too large for removal through the papilla. Endoscopic sphincterotomy was complete in both groups. Patients could switch to ES-LBD if the conventional procedure failed. Results There was no between-group difference in number and size of stones. CBD stone clearance was achieved in 74.0 % of patients in the conventional group and 96.1 % of patients in the ES-LBD group (P < 0.001). Mechanical lithotripsy was needed significantly more often in the conventional group (35.6 % vs. 3.9 %; P < 0.001). There was no difference in terms of morbidity (9.3 % in the conventional group vs. 8.1 % in the ES-LBD group; P = 0.82). The cost and procedure time were not significantly different between the groups overall, but became significantly higher for patients in the conventional group who underwent mechanical lithotripsy. The conventional procedure failed in 19 patients, 15 of whom underwent a rescue ES-LBD procedure that successfully cleared all stones. Conclusions Complete endoscopic sphincterotomy with large-balloon dilation for the removal of large CBD stones has similar safety but superior efficiency to conventional treatment, and should be considered as the first-line step in the treatment of large bile duct stones and in rescue treatment.Trial registered at ClinicalTrials.gov (NCT02592811).

Power and sample size determination for group comparison of patient‐reported outcomes using polytomous Rasch models

The analysis of patient-reported outcomes or other psychological traits can be realized using the Rasch measurement model. When the objective of a study is to compare groups of individuals, it is important, before the study, to define a sample size such that the group comparison test will attain a given power. The Raschpower procedure (RP) allows doing so with dichotomous items. The RP is extended to polytomous items. Several computational issues were identified, and adaptations have been proposed. The performance of this new version of RP is assessed using simulations. This adaptation of RP allows obtaining a good estimate of the expected power of a test to compare groups of patients in a large number of practical situations. A Stata module, as well as its implementation online, is proposed to perform the RP. Two versions of the RP for polytomous items are proposed (deterministic and stochastic versions). These two versions produce similar results in all of the tested cases. We recommend the use of the deterministic version, when the measure is obtained using small questionnaires or items with a few number of response categories, and the stochastic version elsewhere, so as to optimize computing time.

Harmonizing Screening for Gambling Problems in Epidemiological Surveys – Development of the Rapid Screener for Problem Gambling (RSPG)

Background and aims The aim of this study was to test the screening properties of several combinations of items from gambling scales, in order to harmonize screening of gambling problems in epidemiological surveys. The objective was to propose two brief screening tools (three items or less) for a use in interviews and self-administered questionnaires. Methods We tested the screening properties of combinations of items from several gambling scales, in a sample of 425 gamblers (301 non-problem gamblers and 124 disordered gamblers). Items tested included interview-based items (Pathological Gambling section of the DSM-IV, lifetime history of problem gambling, monthly expenses in gambling, and abstinence of 1 month or more) and self-report items (South Oaks Gambling Screen, Gambling Attitudes, and Beliefs Survey). The gold standard used was the diagnosis of a gambling disorder according to the DSM-5. Results Two versions of the Rapid Screener for Problem Gambling (RSPG) were developed: the RSPG-Interview (RSPG-I), being composed of two interview items (increasing bets and loss of control), and the RSPG-Self-Assessment (RSPG-SA), being composed of three self-report items (chasing, guiltiness, and perceived inability to stop). Discussion and conclusions We recommend using the RSPG-SA/I for screening problem gambling in epidemiological surveys, with the version adapted for each purpose (RSPG-I for interview-based surveys and RSPG-SA for self-administered surveys). This first triage of potential problem gamblers must be supplemented by further assessment, as it may overestimate the proportion of problem gamblers. However, a first triage has the great advantage of saving time and energy in large-scale screening for problem gambling.

Study protocol for a transversal study to develop a screening model for excessive gambling behaviours on a representative sample of users of French authorised gambling websites

Introduction Since the legalisation of online gambling in France in 2010, gambling operators must implement responsible gambling measures to prevent excessive gambling practices. However, actually there is no screening procedure for identifying problematic gamblers. Although several studies have already been performed using several data sets from online gambling operators, the authors deplored several methodological and clinical limits that prevent scientifically validating the existence of problematic gambling behaviour. The aim of this study is to develop a model for screening excessive gambling practices based on the gambling behaviours observed on French gambling websites, coupled with a clinical validation. Methods and analysis The research is divided into three successive stages. All analyses will be performed for each major type of authorised online gambling in France. The first stage aims at defining a typology of users of French authorised gambling websites based on their gambling behaviour. This analysis will be based on data from the Authority for Regulating Online Gambling (ARJEL) and the Française Des Jeux (FDJ). For the second stage aiming at determining a score to predict whether a gambler is problematic or not, we will cross answers from the Canadian Problem Gambling Index with real gambling data. The objective of the third stage is to clinically validate the score previously developed. Results from the screening model will be compared (using sensitivity, specificity, area under the curve, and positive and negative predictive values) with the diagnosis obtained with a telephone clinical interview, including diagnostic criteria for gambling addiction. Ethics and dissemination This study was approved by the local Research Ethics Committee (GNEDS) on 25 March 2015. Results will be presented in national and international conferences, submitted to peer-reviewed journals and will be part of a PhD thesis. A final report with the study results will be presented to the ARJEL, especially the final screening model. Trial registration number NCT02415296.

Gambling among European professional athletes. Prevalence and associated factors.

ABSTRACT In Europe, the prevalence of gambling disorders in the general population ranges from 0.15 to 6.6%. Professional athletes are known for having risk factors for addictive behaviors, such as young age or sensation seeking, though no study has yet tried to evaluate the prevalence of gambling and gambling disorders among this specific population. The goals of this study were to estimate the prevalence of gambling, problematic or not, among European professional athletes and to explore the factors that are associated with gambling practice and gambling problems in professional athletes. A self-completion questionnaire was specifically designed for this study. The questionnaires were distributed by European Union athletes to professional ice hockey, rugby, handball, basketball, football, indoor football, volleyball, and cricket teams in Spain, France, Greece, Ireland, Italy, Sweden, and the United Kingdom. Socio-demographic variables (age, sex, education, marital and parental status, sport, country of birth, and country of practice), variables linked to gambling (gambling habits, screening of gambling problems with the Lie/Bet questionnaire, and gambling related cognitions), and impulsive behavior data (urgency, premeditation, perseverance, and sensation seeking [UPPS]-Short Form questionnaire) were gathered. There were 1,236 questionnaires filled out. The percentage of professional athletes that had gambled at least once during the previous year was 56.6%. The prevalence of problem gambling, current or past, was 8.2%. A certain number of variables were associated with the gambling status. In particular, betting on ones own team (OR = 4.1, CI95% [1.5–11.5]), betting online (OR = 2.9, CI95% [1.6–5.4]), gambling regularly (OR = 4.0, CI95% [2.1–7.6]), and having a high positive urgency score (OR = 1.5, CI95% [1.3–1.7]) were associated with gambling problems, current or past, among professional athletes. Professional athletes are particularly exposed to both gambling and problem gambling.

Power and sample size determination for the group comparison of patient-reported outcomes using the Rasch model: impact of a misspecification of the parameters

BackgroundPatient-reported outcomes (PRO) are important as endpoints in clinical trials and epidemiological studies. Guidelines for the development of PRO instruments and analysis of PRO data have emphasized the need to report methods used for sample size planning. The Raschpower procedure has been proposed for sample size and power determination for the comparison of PROs in cross-sectional studies comparing two groups of patients when an item reponse model, the Rasch model, is intended to be used for analysis. The power determination of the test of the group effect using Raschpower requires several parameters to be fixed at the planning stage including the item parameters and the variance of the latent variable. Wrong choices regarding these parameters can impact the expected power and the planned sample size to a greater or lesser extent depending on the magnitude of the erroneous assumptions.MethodsThe impact of a misspecification of the variance of the latent variable or of the item parameters on the determination of the power using the Raschpower procedure was investigated through the comparison of the estimations of the power in different situations.ResultsThe power of the test of the group effect estimated with Raschpower remains stable or shows a very little decrease whatever the values of the item parameters. For most of the cases, the estimated power decreases when the variance of the latent trait increases. As a consequence, an underestimation of this variance will lead to an overestimation of the power of the group effect.ConclusionA misspecification of the item difficulties regarding their overall pattern or their dispersion seems to have no or very little impact on the power of the test of the group effect. In contrast, a misspecification of the variance of the latent variable can have a strong impact as an underestimation of the variance will lead in some cases to an overestimation of the power at the design stage and may result in an underpowered study.