Network Meta-Analysis Techniques for Synthesizing Prevention Science Evidence.

Network meta-analysis is a popular statistical technique for synthesizing evidence from studies comparing multiple interventions. Benefits of network meta-analysis, over more traditional pairwise meta-analysis approaches, include evaluating efficacy/safety of interventions within a single framework, increased precision, comparing pairs of interventions that have never been directly compared in a trial, and providing a hierarchy of interventions in terms of their effectiveness. Network meta-analysis is relatively underutilized in prevention science. This paper therefore presents a primer of network meta-analysis for prevention scientists who wish to apply this method or to critically appraise evidence from publications using the method. We introduce the key concepts and assumptions of network meta-analysis, namely, transitivity and consistency, and demonstrate their applicability to the field of prevention science. We then illustrate the method using a network meta-analysis examining the comparative effectiveness of brief alcohol interventions for preventing hazardous drinking among college students. We provide data and code for all examples. Finally, we discuss considerations that are particularly relevant in network meta-analyses in the field of prevention, such as including non-randomized evidence.

A short, 8-week course of imiquimod 5% cream versus podophyllotoxin in the treatment of anogenital warts: A retrospective comparative cohort study.

BACKGROUND: Studies comparing head-to-head treatment modalities for anogenital warts are lacking. AIM: We sought to compare a short, 8-week course of imiquimod 5% cream to versus the standard 4 week course of podophyllotoxin in the treatment of anogenital warts and to assess factors that may affect response to treatment. METHODS: This was a retrospective cohort study. We reviewed medical files of otherwise healthy patients with a first episode of anogenital warts who were treated with either a short, 8-week course of imiquimod or the standard 4-week course of podophyllotoxin. Inverse probability of treatment weighted (IPTW). Logistic regression was employed to evaluate factors that may affect response to therapy. RESULTS: The study included 347 patients. In patients with lesions on dry, keratinized anatomical sites, the complete clearance rates were 7.6% for imiquimod and 27.9% for podophyllotoxin (P < 0.001). In patients with lesions on moist, partially keratinized sites, no difference between the treatments was revealed. Significant predictors of > 50% reduction in wart area were location of lesions [odds ratio (OR) (95% confidence interval (CI)): 3.6 (1.84-7.08), P = 0.0002] for "partially keratinized" versus "keratinized" sites and treatment used [OR (95% CI): 1.79 (1.08-2.97), P = 0.024] for podophyllotoxin versus imiquimod. LIMITATIONS: The retrospective design of the study was a limitation that we mitigated against with the use of IPTW logistic regression. CONCLUSION: A standard 4 week course of Podophyllotoxin was more effective than an 8-week course of imiquimod only for lesions on keratinized sites. Treatment with podophyllotoxin and location of lesions on partially keratinized sites were independent predictors of >50% reduction in wart area.

Bayesian sample size re-estimation using power priors.

The sample size of a randomized controlled trial is typically chosen in order for frequentist operational characteristics to be retained. For normally distributed outcomes, an assumption for the variance needs to be made which is usually based on limited prior information. Especially in the case of small populations, the prior information might consist of only one small pilot study. A Bayesian approach formalizes the aggregation of prior information on the variance with newly collected data. The uncertainty surrounding prior estimates can be appropriately modelled by means of prior distributions. Furthermore, within the Bayesian paradigm, quantities such as the probability of a conclusive trial are directly calculated. However, if the postulated prior is not in accordance with the true variance, such calculations are not trustworthy. In this work we adapt previously suggested methodology to facilitate sample size re-estimation. In addition, we suggest the employment of power priors in order for operational characteristics to be controlled.

Rapid on-site evaluation during endoscopic ultrasound-guided fine-needle aspiration of lymph nodes does not increase diagnostic yield: A randomized, multicenter trial.

OBJECTIVES: Studies on the impact of rapid on-site evaluation (ROSE) during endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of lymph nodes are retrospective and have shown conflicting results. We aimed to compare the diagnostic yield of EUS-FNA of lymph nodes with ROSE (ROSE+) and without ROSE (ROSE-). METHODS: This was a multicenter, randomized controlled trial. Consecutive patients who were scheduled to undergo EUS-FNA of mediastinal or abdominal lymph nodes were randomized to ROSE+ or ROSE-. In the ROSE+ group, the number of passes was dictated by the on-site cytotechnician. In the ROSE- group, five passes were performed without interference from the cytotechnician. All samples were reviewed by a single-expert cytopathologist, blinded to group allocation. Primary endpoint was diagnostic yield with and without ROSE. RESULTS: After inclusion of 90 patients, interim analysis showed futility of study continuation since diagnostic yield of ROSE+ and ROSE- were comparable. A total of 91 patients were randomized to ROSE+ (N = 45) or ROSE- (N = 46). Diagnostic yield of ROSE+ and ROSE- and diagnostic accuracy were comparable: 93.3% vs. 95.7% (P = 0.68) and 97.6% vs. 93.2% (P = 0.62), respectively. Two major complications (one per group) occurred (p = 0.99). ROSE- patients more often reported self-limiting post-procedural pain (p < 0.001). Median procedure time for ROSE+ (20 min) and ROSE- (23 min) was comparable (P = 0.06). Median time to review slides in the ROSE- group (12:47 min) was longer than with ROSE+ (7:52 min) (P < 0.001). Mean costs of ROSE- and ROSE+ were comparable: €938.29 (±172.70) vs. €945.98 (±223.38) (P = 0.91), respectively. CONCLUSIONS: Diagnostic yield and accuracy of EUS-FNA of mediastinal and abdominal lymph nodes with and without ROSE are comparable. Time needed to review slides was shorter and post-procedural pain was less often reported in the ROSE+ group. Based on the primary outcome, the implementation of ROSE during EUS-FNA of mediastinal and abdominal lymph nodes cannot be advised. (Dutch Trial Register: NTR4876).

A comparative study of brachial plexus sonography and magnetic resonance imaging in chronic inflammatory demyelinating neuropathy and multifocal motor neuropathy.

BACKGROUND AND PURPOSE: To compare the performance of neuroimaging techniques, i.e. high-resolution ultrasound (HRUS) and magnetic resonance imaging (MRI), when applied to the brachial plexus, as part of the diagnostic work-up of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN). METHODS: Fifty-one incident, treatment-naive patients with CIDP (n = 23) or MMN (n = 28) underwent imaging of the brachial plexus using (i) a standardized MRI protocol to assess enlargement or T2 hyperintensity and (ii) bilateral HRUS to determine the extent of nerve (root) enlargement. RESULTS: We found enlargement of the brachial plexus in 19/51 (37%) and T2 hyperintensity in 29/51 (57%) patients with MRI and enlargement in 37/51 (73%) patients with HRUS. Abnormal results were only found in 6/51 (12%) patients with MRI and 12/51 (24%) patients with HRUS. A combination of the two imaging techniques identified 42/51 (83%) patients. We found no association between age, disease duration or Medical Research Council sum-score and sonographic nerve size, MRI enlargement or presence of T2 hyperintensity. CONCLUSIONS: Brachial plexus sonography could complement MRI in the diagnostic work-up of patients with suspected CIDP and MMN. Our results indicate that combined imaging studies may add value to the current diagnostic consensus criteria for chronic inflammatory neuropathies.