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Background: The threat of a possible Marburg virus disease outbreak in Central and Western Africa is growing. While no Marburg virus vaccines are currently available for use, several candidates are in the pipeline. Building on knowledge and experiences in the designs of vaccine efficacy trials against other pathogens, including SARS-CoV-2, we develop designs of randomized Phase 3 vaccine efficacy trials for Marburg virus vaccines. Methods: A core protocol approach will be used, allowing multiple vaccine candidates to be tested against controls. The primary objective of the trial will be to evaluate the effect of each vaccine on the rate of virologically confirmed Marburg virus disease, although Marburg infection assessed via seroconversion could be the primary objective in some cases. The overall trial design will be a mixture of individually and cluster-randomized designs, with individual randomization done whenever possible. Clusters will consist of either contacts and contacts of contacts of index cases, that is, ring vaccination, or other transmission units. Results: The primary efficacy endpoint will be analysed as a time-to-event outcome. A vaccine will be considered successful if its estimated efficacy is greater than 50% and has sufficient precision to rule out that true efficacy is less than 30%. This will require approximately 150 total endpoints, that is, cases of confirmed Marburg virus disease, per vaccine/comparator combination. Interim analyses will be conducted after 50 and after 100 events. Statistical analysis of the trial will be blended across the different types of designs. Under the assumption of a 6-month attack rate of 1% of the participants in the placebo arm for both the individually and cluster-randomized populations, the most likely sample size is about 20,000 participants per arm. Conclusion: This event-driven design takes into the account the potentially sporadic spread of Marburg virus. The proposed trial design may be applicable for other pathogens against which effective vaccines are not yet available. [ABSTRACT FROM AUTHOR]

Background: The REGAIN (Regional versus General Anesthesia for Promoting Independence after Hip Fracture) trial found similar ambulation and survival at 60 days with spinal versus general anesthesia for hip fracture surgery. Trial outcomes evaluating pain, prescription analgesic use, and patient satisfaction have not yet been reported.Objective: To compare pain, analgesic use, and satisfaction after hip fracture surgery with spinal versus general anesthesia.Design: Preplanned secondary analysis of a pragmatic randomized trial. (ClinicalTrials.gov: NCT02507505).Setting: 46 U.S. and Canadian hospitals.Participants: Patients aged 50 years or older undergoing hip fracture surgery.Intervention: Spinal or general anesthesia.Measurements: Pain on postoperative days 1 through 3; 60-, 180-, and 365-day pain and prescription analgesic use; and satisfaction with care.Results: A total of 1600 patients were enrolled. The average age was 78 years, and 77% were women. A total of 73.5% (1050 of 1428) of patients reported severe pain during the first 24 hours after surgery. Worst pain over the first 24 hours after surgery was greater with spinal anesthesia (rated from 0 [no pain] to 10 [worst pain imaginable]; mean difference, 0.40 [95% CI, 0.12 to 0.68]). Pain did not differ across groups at other time points. Prescription analgesic use at 60 days occurred in 25% (141 of 563) and 18.8% (108 of 574) of patients assigned to spinal and general anesthesia, respectively (relative risk, 1.33 [CI, 1.06 to 1.65]). Satisfaction was similar across groups.Limitation: Missing outcome data and multiple outcomes assessed.Conclusion: Severe pain is common after hip fracture. Spinal anesthesia was associated with more pain in the first 24 hours after surgery and more prescription analgesic use at 60 days compared with general anesthesia.Primary Funding Source: Patient-Centered Outcomes Research Institute. [ABSTRACT FROM AUTHOR]

BACKGROUND/OBJECTIVES: Accurate estimates of clinically important difference (CID) are required for interpreting the clinical importance of treatments to improve physical function, but CID estimates vary in different disease populations. We determined the CID for two common measures of walking ability in mobility‐limited older men. Design: Longitudinal, multisite placebo‐controlled trial. Setting/Participants: Men enrolled in the Testosterone Trials who had self‐reported mobility limitation and gait speed less than 1.2 m/second (n = 429). Testosterone‐ and placebo‐allocated participants were combined for this study. RESULTS: Mean changes from baseline, adjusting for time‐in‐intervention and site, were 29.6, 13.2, 12.5, −2.4, and −32.6 m for 6MWD, and 15.4, 7.2, 2.1, −3.4, and −7.2 for PF10 in men who reported their mobility was "very/much better," "little better," "no change," "little worse," or "much worse," respectively. CID estimates using regression, ROC, and eCDF varied from 5.0–29.6 m for 6MWD, and 5.0–15.2 points for PF10. CONCLUSION: CID estimates vary by the population studied and by the method and precision of measurement. Increases of 16 to 30 m for 6MWD and 5 to 15 points for PF10 over 12 months appear to be clinically meaningful in mobility‐limited, older hypogonadal men. These CID estimates may be useful in the design of efficacy trials of therapies to improve physical function. [ABSTRACT FROM AUTHOR]

Background/aims: Noninferiority clinical trials are susceptible to false confirmation of noninferiority when the intention-to-treat principle is applied in the setting of incomplete trial protocol adherence. The risk increases as protocol adherence rates decrease. The objective of this study was to compare protocol adherence and hypothesis confirmation between superiority and noninferiority randomized clinical trials published in three high impact medical journals. We hypothesized that noninferiority trials have lower protocol adherence and greater hypothesis confirmation. Methods: We conducted an observational study using published clinical trial data. We searched PubMed for active control, two-arm parallel group randomized clinical trials published in JAMA: The Journal of the American Medical Association, The New England Journal of Medicine, and The Lancet between 2007 and 2017. The primary exposure was trial type, superiority versus noninferiority, as determined by the hypothesis testing framework of the primary trial outcome. The primary outcome was trial protocol adherence rate, defined as the number of randomized subjects receiving the allocated intervention as described by the trial protocol and followed to primary outcome ascertainment (numerator), over the total number of subjects randomized (denominator). Hypothesis confirmation was defined as affirmation of noninferiority or the alternative hypothesis for noninferiority and superiority trials, respectively. Results: Among 120 superiority and 120 noninferiority trials, median and interquartile protocol adherence rates were 91.5 [81.4–96.7] and 89.8 [83.6–95.2], respectively; P = 0.47. Hypothesis confirmation was observed in 107/120 (89.2%) of noninferiority and 64/120 (53.3%) of superiority trials, risk difference (95% confidence interval): 35.8 (25.3–46.3), P < 0.001. Conclusion: Protocol adherence rates are similar between superiority and noninferiority trials published in three high impact medical journals. Despite this, we observed greater hypothesis confirmation among noninferiority trials. We speculate that publication bias, lenient noninferiority margins and other sources of bias may contribute to this finding. Further study is needed to identify the reasons for this observed difference. [ABSTRACT FROM AUTHOR]

Rationale: Low and slow patient enrollment remains a barrier to critical care randomized controlled trials (RCTs). Behavioral economic insights suggest that nudges may address some enrollment challenges.Objectives: To evaluate the efficacy of a novel preconsent survey consisting of nudges on critical care RCT enrollment.Methods: We conducted an RCT in 10 intensive care units (ICUs) among surrogate decision-makers (SDMs). The novel multicomponent behavioral nudge survey was administered immediately before soliciting SDMs' informed consent for their patients' participation in a sham trial of two mechanical ventilation weaning approaches in acute respiratory failure. The primary outcome was the enrollment rate for the sham trial. Secondary outcomes included undue and unjust inducements. We also explored SDM and patient predictors of enrollment using multivariate regression.Results: Among 182 SDMs, 93 were randomized to receive the intervention survey and 89 to receive standard informed consent. There was no statistically significant difference in enrollment rates between the intervention (29%) and standard consent (34%) groups (percentage difference, 5%; 95% confidence interval [CI], -9% to 18%; P = 0.50). There was no evidence of undue or unjust inducement. White SDMs were more likely to enroll the patient compared with non-white SDMs (odds ratio, 3.7; 95% CI, 1.1 to 12.2; P = 0.03). SDMs who perceived a higher risk of participation were less likely to enroll the patient (odds ratio, 0.57; 95% CI, 0.46 to 0.71; P < 0.001).Conclusions: A preconsent behavioral nudge survey among SDMs of patients with acute respiratory failure in the ICU did not increase enrollment rates for a sham RCT compared with standard informed consent procedures.Clinical trial registered with ClinicalTrials.gov (NCT03284359). [ABSTRACT FROM AUTHOR]

Background: We wished to compare the nuisance parameters of pediatric vs. adult randomized-trials (RCTs) and determine if the latter can be used in sample size computations of the former.Methods: In this meta-epidemiologic empirical evaluation we examined meta-analyses from the Cochrane Database of Systematic-Reviews, with at least one pediatric-RCT and at least one adult-RCT. Within each meta-analysis of binary efficacy-outcomes, we calculated the pooled-control-group event-rate (CER) across separately all pediatric and adult-trials, using random-effect models and subsequently calculated the control-group event-rate risk-ratio (CER-RR) of the pooled-pediatric-CERs vs. adult-CERs. Within each meta-analysis with continuous outcomes we calculated the pooled-control-group effect standard deviation (CE-SD) across separately all pediatric and adult-trials and subsequently calculated the CE-SD-ratio of the pooled-pediatric-CE-SDs vs. adult-CE-SDs. We then calculated across all meta-analyses the pooled-CER-RRs and pooled-CE-SD-ratios (primary endpoints) and the pooled-magnitude of effect-sizes of CER-RRs and CE-SD-ratios using REMs. A ratio < 1 indicates that pediatric trials have smaller nuisance parameters than adult trials.Results: We analyzed 208 meta-analyses (135 for binary-outcomes, 73 for continuous-outcomes). For binary outcomes, pediatric-RCTs had on average 10% smaller CERs than adult-RCTs (summary-CE-RR: 0.90; 95% CI: 0.83, 0.98). For mortality outcomes the summary-CE-RR was 0.48 (95% CIs: 0.31, 0.74). For continuous outcomes, pediatric-RCTs had on average 26% smaller CE-SDs than adult-RCTs (summary-CE-SD-ratio: 0.74).Conclusions: Clinically relevant differences in nuisance parameters between pediatric and adult trials were detected. These differences have implications for design of future studies. Extrapolation of nuisance parameters for sample-sizes calculations from adult-trials to pediatric-trials should be cautiously done. [ABSTRACT FROM AUTHOR]

The article discusses the use of randomized controlled trials (RCTs) and other alternative methods to study the effects of medical treatments, and it mentions resistance to RCTs based on ethical grounds, treatments for diseases such as AIDS, and information about patients' treatment expectations. Uncontolled research studies and the Cardiac Arrhythmia Suppression Trial (CAST) are examined, along with the 2014-2015 Ebola Virus Disease epidemic and AIDS activists' views.

Background: Pragmatic trials comparing standard-of-care interventions may improve the quality of care for future patients, but raise ethical questions about limitations on decisional autonomy. We sought to understand how patients and physicians view and respond to these questions in the contexts of pragmatic trials and of usual clinical care.Methods: We conducted scenario-based, semistructured interviews with 32 patients with end-stage renal disease (ESRD) receiving maintenance hemodialysis in outpatient dialysis units and with 24 nephrologists. Each participant was presented with two hypothetical scenarios in which a protocolized approach to hemodialysis treatment time was adopted for the entire dialysis unit as part of a clinical trial or a new clinical practice.Results: A modified grounded theory analysis revealed three major themes: (1) the value of research, (2) the effect of protocolized care on patient and physician autonomy, and (3) information exchange between patients and physicians, including the mechanism of consent. Most patients and physicians were willing to relinquish decisional autonomy and were more willing to relinquish autonomy for research purposes than in clinical care. Patients' concerns toward clinical trials were tempered by their desires for certainty for a positive outcome and for physician validation. Patients tended to believe that being informed about research was more important than the actual mechanism of consent, and most were content with being able to opt out from participating.Conclusions: This qualitative study suggests the general acceptability of a pragmatic clinical trial comparing standard-of-care interventions that limits decisional autonomy for nephrologists and patients receiving hemodialysis. Future studies are needed to determine whether similar findings would emerge among other patients and providers considering other standard-of-care trials. [ABSTRACT FROM AUTHOR]

Background: Adenotonsillectomy (AT) is commonly performed for childhood OSA syndrome (OSAS), but little is known about prognosis without treatment.Methods: The Childhood Adenotonsillectomy Trial (CHAT) randomized 50% of eligible children with OSAS to a control arm (watchful waiting), with 7-month follow-up symptom inventories, physical examinations, and polysomnography. Polysomnographic and symptomatic resolution were defined respectively by an apnea/hypopnea index (AHI) <2 and obstructive apnea index (OAI) <1 and by an OSAS symptom score (Pediatric Sleep Questionnaire [PSQ]) < 0.33 with ≥ 25% improvement from baseline.Results: After 194 children aged 5 to 9 years underwent 7 months of watchful waiting, 82 (42%) no longer met polysomnographic criteria for OSAS. Baseline predictors of resolution included lower AHI, better oxygen saturation, smaller waist circumference or percentile, higher-positioned soft palate, smaller neck circumference, and non-black race (each P < .05). Among these, the independent predictors were lower AHI and waist circumference percentile < 90%. Among 167 children with baseline PSQ scores ≥ 0.33, only 25 (15%) experienced symptomatic resolution. Baseline predictors were low PSQ and PSQ snoring subscale scores; absence of habitual snoring, loud snoring, observed apneas, or a household smoker; higher quality of life; fewer attention-deficit/hyperactivity disorder symptoms; and female sex. Only lower PSQ and snoring scores were independent predictors.Conclusions: Many candidates for AT no longer have OSAS on polysomnography after 7 months of watchful waiting, whereas meaningful improvement in symptoms is not common. In practice, a baseline low AHI and normal waist circumference, or low PSQ and snoring score, may help identify an opportunity to avoid AT.Trial Registry: ClinicalTrials.gov; No.: NCT00560859; URL: www.clinicaltrials.gov. [ABSTRACT FROM AUTHOR]

Randomized clinical trials are the most reliable approaches to evaluating the effects of new treatments and vaccines. During the 2014-2015 West African Ebola epidemic, many argued that such trials were neither ethical nor feasible in an environment of limited health infrastructure and severe disease with a high fatality rate. Consensus among the numerous organizations providing help to the affected areas was never achieved, resulting in fragmented collaboration, delayed study initiation and ultimately failure to provide definitive evidence on the efficacy of treatments and vaccines. Randomized trials were in fact approved by local ethics boards and initiated, demonstrating that randomized trials, even in such difficult circumstances, are feasible. Improved planning and collaboration among research and humanitarian organizations, and affected communities, in the interepidemic periods are needed to ensure that questions regarding the efficacy of vaccines and treatments can be definitively answered during future public health emergencies. [ABSTRACT FROM AUTHOR]

This JAMA Guide to Statistics and Methods discusses the stepped-wedge apporach to cluster randomized clinical trial design, in which clusters are randomized to the order in which they receive the experimental regimen. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Stopping Randomized Trials Early for Benefit and Estimation of Treatment Effects: Systematic Review and Meta-Regression Analysis," by Dirk Bassler and colleagues in the 2010 issue.

OBJECTIVE: Research reveals mixed evidence for the effects of adenotonsillectomy (AT) on cognitive tests in children with obstructive sleep apnea syndrome (OSAS). The primary aim of the study was to investigate effects of AT on cognitive test scores in the randomized Childhood Adenotonsillectomy Trial. METHODS: Children ages 5 to 9 years with OSAS without prolonged oxyhemoglobin desaturation were randomly assigned to watchful waiting with supportive care (n = 227) or early AT (eAT, n = 226). Neuropsychological tests were administered before the intervention and 7 months after the intervention. Mixed model analysis compared the groups on changes in test scores across follow-up, and regression analysis examined associations of these changes in the eAT group with changes in sleep measures. RESULTS: Mean test scores were within the average range for both groups. Scores improved significantly (P < .05) more across follow-up for the eAT group than for the watchful waiting group. These differences were found only on measures of nonverbal reasoning, fine motor skills, and selective attention and had small effects sizes (Cohen's d, 0.20-0.24). As additional evidence for AT-related effects on scores, gains in test scores for the eAT group were associated with improvements in sleep measures. CONCLUSIONS: Small and selective effects of AT were observed on cognitive tests in children with OSAS without prolonged desaturation. Relative to evidence from Childhood Adenotonsillectomy Trial for larger effects of surgery on sleep, behavior, and quality of life, AT may have limited benefits in reversing any cognitive effects of OSAS, or these benefits may require more extended follow-up to become manifest. [ABSTRACT FROM AUTHOR]