Proceedings of the 13th annual conference of INEBRIA

CITATION: Watson, R., et al. 2016. Proceedings of the 13th annual conference of INEBRIA. Addiction Science & Clinical Practice, 11:13, doi:10.1186/s13722-016-0062-9.The original publication is available at https://ascpjournal.biomedcentral.comENGLISH SUMMARY : Meeting abstracts.https://ascpjournal.biomedcentral.com/articles/10.1186/s13722-016-0062-9Publisher's versio

Impact of complex, partially nested clustering in a three-arm individually randomized group treatment trial: A case study with the wHOPE trial

Background/aimsWhen participants in individually randomized group treatment trials are treated by multiple clinicians or in multiple group treatment sessions throughout the trial, this induces partially nested clusters which can affect the power of a trial. We investigate this issue in the Whole Health Options and Pain Education trial, a three-arm pragmatic, individually randomized clinical trial. We evaluate whether partial clusters due to multiple visits delivered by different clinicians in the Whole Health Team arm and dynamic participant groups due to changing group leaders and/or participants across treatment sessions during treatment delivery in the Primary Care Group Education arm may impact the power of the trial. We also present a Bayesian approach to estimate the intraclass correlation coefficients.MethodsWe present statistical models for each treatment arm of Whole Health Options and Pain Education trial in which power is estimated under different intraclass correlation coefficients and mapping matrices between participants and clinicians or treatment sessions. Power calculations are based on pairwise comparisons. In practice, sample size calculations depend on estimates of the intraclass correlation coefficients at the treatment sessions and clinician levels. To accommodate such complexities, we present a Bayesian framework for the estimation of intraclass correlation coefficients under different participant-to-session and participant-to-clinician mapping scenarios. We simulated continuous outcome data based on various clinical scenarios in Whole Health Options and Pain Education trial using a range of intraclass correlation coefficients and mapping matrices and used Gibbs samplers with conjugate priors to obtain posteriors of the intraclass correlation coefficients under those different scenarios. Posterior means and medians and their biases are calculated for the intraclass correlation coefficients to evaluate the operating characteristics of the Bayesian intraclass correlation coefficient estimators.ResultsPower for Whole Health Team versus Primary Care Group Education is sensitive to the intraclass correlation coefficient in the Whole Health Team arm. In these two arms, an increased number of clinicians, more evenly distributed workload of clinicians, or more homogeneous treatment group sizes leads to increased power. Our simulation study for the intraclass correlation coefficient estimation indicates that the posterior mean intraclass correlation coefficient estimator has less bias when the true intraclass correlation coefficients are large (i.e. 0.10), but when the intraclass correlation coefficient is small (i.e. 0.01), the posterior median intraclass correlation coefficient estimator is less biased.ConclusionKnowledge of intraclass correlation coefficients and the structure of clustering are critical to the design of individually randomized group treatment trials with partially nested clusters. We demonstrate that the intraclass correlation coefficient of the Whole Health Team arm can affect power in the Whole Health Options and Pain Education trial. A Bayesian approach provides a flexible procedure for estimating the intraclass correlation coefficients under complex scenarios. More work is needed to educate the research community about the individually randomized group treatment design and encourage publication of intraclass correlation coefficients to help inform future trial designs

Abstract 334: Impact of Sex, Gender and Healthcare System on the Quality of Care in Young Adults With Acute Myocardial Infarction

Background: The quality of care among young adults with acute myocardial infarction (AMI) may be related to biological (sex) or psycho-socio-cultural (gender) determinants or healthcare system-level factors. Objectives: To examine whether sex, gender, and the type of healthcare system influence the quality of AMI care among young adults. Methods: A total of 4,564 AMI young adults (<55 years) (59% women, 47 years, 66% US) were analyzed from the VIRGO and GENESIS-PRAXY studies consisting of single-payer (Canada, Spain) versus multipayer (US) systems. For each patient treated in each system, we calculated a quality of care score (QCS) for pre-AMI (1-year pre-admission), in-hospital, and post-AMI (1-year post-discharge) phases of care (the number of quality indicators received divided by the total number [range=0-100%], with higher scores indicating better quality). The standard quality of care indicators were selected on the basis of being the standard of care to which young adults with AMI should have access to, based on European and North American Guidelines. Ordinal logistic or linear regression models and 2-way interactions between sex, gender and healthcare system were tested. Results: Women in the multipayer system had the highest risk factor burden. Across the phases of care for AMI, 20% of quality indicators were missed in both sexes. High stress, earner status, and social support were associated with a higher QCS in the pre-AMI phase, whereas only employment and earner status were associated with QCS in all other phases. In the pre-AMI phase, women had higher QCS than men, mainly in the single-payer system (adjusted-OR=1.85, 95%CI 1.46,2.35 vs. 1.07, 95%CI 0.84,1.36, P-interaction=0.002). Regardless of sex, only employment status had a greater effect in the multipayer system (adjusted-OR=0.59, 95%CI 0.44,0.78 vs 1.13, 95%CI 0.89,1.44, P-interaction<0.001). In the in-hospital phase, women had a lower QCS than men, especially in the multipayer system (adjusted-mean-difference: -2.48, 95%CI-3.87,-1.08). Employment was associated with a higher QCS (2.0, 95%CI 0.9-3.17, P interaction >0.05). Finally, in the post-AMI phase, men and women had a lower QCS, predominantly in the multipayer system. However, primary earners had higher QCS regardless of the healthcare system. Conclusion: Sex, gender, and the healthcare system affected the quality of care after AMI. Women had a poorer in-hospital than men and young adults had suboptimal post-discharge care. Being unemployed lowered the quality of care, more so in the multipayer healthcare system

Is It Safe to Delay Appendectomy in Adults With Acute Appendicitis?

OBJECTIVE: To examine whether delayed surgical intervention in adult patients with acute appendicitis is safe by correlating the interval from onset of symptoms to operation (total interval) with the degree of pathology and incidence of postoperative complications. SUMMARY BACKGROUND DATA: Prompt appendectomy has long been the standard of care for acute appendicitis because of the risk of progression to advanced pathology. This time-honored practice has been recently challenged by studies in pediatric patients, which suggested that acute appendicitis can be managed in an elective manner once antibiotic therapy is initiated. No such data are available in adult patients with acute appendicitis. METHODS: A retrospective review of 1081 patients who underwent an appendectomy for acute appendicitis between 1998 and 2004 was conducted. The following parameters were monitored and correlated: demographics, time from onset of symptoms to arrival at the emergency room (patient interval) and from arrival to the emergency room to the operating room (hospital interval), physical, computed tomography (CT scan) and pathologic findings, complications, length of stay, and length of antibiotic treatment. Pathologic state was graded 1 (G1) for acute appendicitis, 2 (G2) for gangrenous acute appendicitis, 3 (G3) for perforation or phlegmon, and 4 (G4) for a periappendicular abscess. RESULTS: The risk of advanced pathology, defined as a higher pathology grade, increased with the total interval. When this interval was <12 hours, the risk of developing G1, G2, G3, and G4, was 94%, 0%, 3%, and 3%, respectively. These values changed to 60%, 7%, 27%, and 6%, respectively, when the total interval was 48 to 71 hours and to 54%, 7%, 26%, and 13% for longer than 71 hours. The odds for progressive pathology was 13 times higher for the total interval >71 hours group compared with total interval<12 hours (95% confidence interval = 4.7–37.1). Although both prolonged patient and hospital intervals were associated with advanced pathology, prehospital delays were more profoundly related to worsening pathology compared with in-hospital delays (P < 0.001). Advanced pathology was associated with tenderness to palpation beyond the right lower quadrant (P < 0.001), guarding (P < 0.001), rebound (P < 0.001), and CT scan findings of peritoneal fluid (P = 0.01), fecalith (P = 0.01), dilation of the appendix (P < 0.001), and perforation (P < 0.001). Increased length of hospital stay (P < 0.001) and antibiotic treatment (P < 0.001) as well as postoperative complications (P < 0.001) also correlated with progressive pathology. CONCLUSION: In adult patients with acute appendicitis, the risk of developing advanced pathology and postoperative complications increases with time; therefore, delayed appendectomy is unsafe. As delays in seeking medical help are difficult to control, prompt appendectomy is mandatory. Because these conclusions are derived from retrospective data, a prospective study is required to confirm their validity