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Inferences from aggregated data.

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David Jarjoura. 2003. Inferences from aggregated data.. https://doi.org/10.1111/j.1553-2712.2003.tb00633.x

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Assessment of blinding in pharmacotherapy and noninvasive neuromodulation randomized controlled trials for neuropathic pain in adults.

In randomized controlled trials (RCTs), study participants and research personnel are often blinded to minimize biases related to knowing treatment allocation. To determine if blinding was effective, participants may be asked which treatment they believe they received ("treatment guess"). This descriptive review characterized blinding assessment (BA) reporting in pharmacotherapy and neuromodulation neuropathic pain RCTs. Of 288 papers, 36 (12.5%) reported a BA. One paper reported the results of 2 studies, so in total 37 studies with a BA were assessed. Of these, 19 were crossover, 17 parallel, and 1 partial crossover in design. All 37 studies assessed participant blinding, and 10 also assessed investigator blinding. Approximately 27% included an "unsure" answer option for treatment guess, and 38% asked the reason for the guess. There were no clear patterns in BA reporting across time nor based on treatment type. Seventeen trials provided sufficient data to calculate Bang Blinding Index (BI) to determine blinding success. Participants remained blinded (BI = 0 &#xb1; 0.2) in 10/17 placebo and 10/17 treatment arms, 6 placebo and 5 treatment arms had a BI > 0.2 suggesting possible unblinding, whereas 1 placebo and 2 treatment arms had a BI < -0.2 suggesting misinformed guessing. Overall, we found that BAs are done in a minority of published neuropathic pain trials and with variable methodology. Given the importance of minimizing risk of bias because of treatment unblinding, future studies should consider including BAs, and further consensus building is necessary to determine if and how BAs should be conducted and interpreted in analgesic clinical trials.

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Screening of ARDS patients using standardized ventilator settings: influence on enrollment in a clinical trial.

OBJECTIVES: The American-European consensus conference (AECC) definition for acute respiratory distress syndrome (ARDS) requires a PaO(2)/F(I)O(2)< or =200 mmHg, regardless of ventilator settings. We report the results of using standardized ventilator settings to screen and enroll ARDS patients in a clinical trial of high-frequency oscillatory ventilation (HFOV), including the impact on study enrollment, and potential effects on study outcome. DESIGN: Prospective cohort study. SETTING: Intensive care units in two teaching hospitals. PARTICIPANTS. A consecutive sample of 41 patients with early ARDS by AECC criteria (baseline PaO(2)/F(I)O(2)< or =200) who met all other inclusion/exclusion criteria for the HFOV trial. INTERVENTIONS: Patients were placed on standardized ventilator settings (tidal volume 7-8 ml/kg, PEEP 10 cmH(2)O, F(I)O(2) 1.0), and the PaO(2)/F(I)O(2) was reassessed after 30 min. RESULTS: Seventeen patients (41.5%) had PaO(2)/F(I)O(2) ratios that remained < or =200 mmHg [Persistent ARDS; PaO(2)/F(I)O(2)=94+/-36 (mean+/-SD)] and went on to inclusion in the HFOV study; however, in 24 patients (58.5%) the PaO(2)/F(I)O(2) was >200 mmHg [Transient ARDS; PaO(2)/F(I)O(2)=310+/-74] and these patients were ineligible for the HFOV study. The ICU mortality was significantly greater (52.9 vs 12.5%; p=0.01) in the Persistent ARDS patients. CONCLUSIONS: The use of these standardized ventilatory significantly impacted the PaO(2)/F(I)O(2) ratio and therefore the ARDS prevalence and trial enrollment. These results have effects on the evaluation of the current ARDS literature and conduct of clinical trials in ARDS and hence consideration should be given to the use of standardized ventilatory settings in future ARDS trials.

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