Questions concerning the design, analysis, and interpretation of clinical trials

Meinert, Curtis L.; Tonascia, Susan

doi:10.1093/acprof:oso/9780195035681.003.0019

Cited by 25 publications

(29 citation statements)

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“…17 We used ␣ϭ0.05, ␤ϭ0.80, and assumed 2-sided testing and equal group sizes. Sample sizes using the dichotomous mRS or GOS were calculated using:…”

Section: Discussionmentioning

confidence: 99%

Sample Size Estimates for Clinical Trials of Vasospasm in Subarachnoid Hemorrhage

Kreiter

Mayer

Howard

et al. 2009

Stroke

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Background and Purpose-Clinical trials for prevention of vasospasm after aneurysmal subarachnoid hemorrhage (SAH) seldom have improved overall outcome; one reason may be inadequate sample size. We used data from the tirilizad trials and the Columbia University subarachnoid hemorrhage outcomes project to estimate sample sizes for clinical trials for reduction of vasospasm after SAH, assuming trials must show effect on 90-day patient-centered outcome. Methods-Sample size calculations were based on different definitions of vasospasm, enrichment strategies, sensitivity of short-and long-term outcome instruments for reflecting vasospasm-related morbidity, different event rates of vasospasm, calculation of effect size of vasospasm on outcome instruments, and different treatment effect sizes. Sensitivity analysis was performed for variable event rates of vasospasm for a given treatment effect size. Sample size tables were constructed for different rates of vasospasm and outcome instruments for a given treatment effect size. Results-Vasospasm occurred in 12% to 30% of patients. Symptomatic deterioration and infarction from vasospasm exhibited the strongest relationship to mortality and morbidity after SAH. Enriching for vasospasm by selection of patients with thick SAH slightly decreased sample sizes. Assuming ␤ϭ0.80, ␣ϭ0.05 (2-tailed) and treatment effect size of 50%, total sample size exceeds 5000 patients to demonstrate efficacy on 3-month patient-centered outcome (modified Rankin Scale). Conclusions-Clinical trials targeting vasospasm and using traditional patient-centered outcome require very high sample sizes and will therefore be costly, time-consuming, and impractical. This will hinder development of new treatment strategies.

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“…17 We used ␣ϭ0.05, ␤ϭ0.80, and assumed 2-sided testing and equal group sizes. Sample sizes using the dichotomous mRS or GOS were calculated using:…”

Section: Discussionmentioning

confidence: 99%

Sample Size Estimates for Clinical Trials of Vasospasm in Subarachnoid Hemorrhage

Kreiter

Mayer

Howard

et al. 2009

Stroke

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“…There is no simple answer because the study questions reflect the interests, values and motivations of the clinical and research community to provide optimal care for patients. From a methodological standpoint, however, the treatments compared should be (1) distinguishable, (2) medically justifiable, (3) compatible with the needs of the patient, (4) have reasonable doubt regarding relative efficacy, (5) a mode of administration that is compatible with the methodological requirements of the study (for example, concealment is possible when blinding is needed), and (6) a mode of administration that is similar to real-world clinical practice [38].…”

Section: Methodological Aspects Of Outcomes Researchmentioning

confidence: 99%

“…Blinding refers to whether or not the allocation status of a study participant is known or not [38]. Blinding takes place at several levels.…”

Section: Blindingmentioning

confidence: 99%

“…First, it helps ensure that the nature of the treatments remain distinct and separate between the intervention and control arms of the study [38]. For example, if the subject knows the study arm to which they belong, there can be a tendency to seek out the treatment being administered in the opposing arm.…”

Section: Blindingmentioning

confidence: 99%

“…Numerous texts are available for cross-sectional, [26] cohort, [11] case control [45] and randomized clinical trial study designs, [27,38] and the reader is referred to these texts for more information.…”

Section: Correct Statistical Analysismentioning

confidence: 99%

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Methodological aspects of outcomes research

Hiebert

Nordin

2005

Eur Spine J

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Operative vs Nonoperative Treatment for Atraumatic Rotator Cuff Tears

et al. 2019

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Key Points Question What is the comparative effectiveness of operative vs nonoperative treatment for rotator cuff tears? Findings The clinical trial protocol of a pragmatic randomized clinical trial of an estimated 700 patients (with 488 needed for power calculations) is presented. The primary outcome is patient-reported Shoulder Pain and Disability Index score. Meaning The clinical trial is ongoing and will provide data to guide treatment choices for patients with rotator cuff tears.

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Questions concerning the design, analysis, and interpretation of clinical trials

Abstract: This chapter contains a list of questions and short answers concerning the design, analysis, and interpretation of clinical trials. These include questions concerning the study design, the source of study patients, randomization, and masking.

Cited by 25 publications

References 0 publications

Sample Size Estimates for Clinical Trials of Vasospasm in Subarachnoid Hemorrhage

Sample Size Estimates for Clinical Trials of Vasospasm in Subarachnoid Hemorrhage

Methodological aspects of outcomes research

Operative vs Nonoperative Treatment for Atraumatic Rotator Cuff Tears

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