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Impact of Study Partner Replacement in Mild Cognitive Impairment Clinical Trials

In Alzheimer's disease (AD) clinical trials, including trials enrolling patients with mild cognitive impairment (MCI), participants must enroll with a study partner (SP). SPs ensure compliance and are a source of study data, including assessments of …

A review of current practice in the design and analysis of extremely small stepped-wedge cluster randomized trials

Background/Aims - Stepped-wedge cluster randomized trials tend to require fewer clusters than standard parallel-arm designs due to the switches between control and intervention conditions, but there are no recommendations for the minimum number of …

Power calculation for cross-sectional stepped wedge cluster randomized trials with a time-to-event endpoint

A popular design choice in public health and implementation science research, stepped wedge cluster randomized trials (SW-CRTs) are a form of randomized trial whereby clusters are progressively transitioned from control to intervention, and the …

Group sequential two-stage preference designs

The two-stage preference design (TSPD) enables inference for treatment efficacy while allowing for incorporation of patient preference to treatment. It can provide unbiased estimates for selection and preference effects, where a selection effect …

Adherence to key recommendations for design and analysis of stepped-wedge cluster randomized trials - A review of trials published 2016–2022

Background/Aims - The stepped-wedge cluster randomized trial (SW-CRT), in which clusters are randomized to a time at which they will transition to the intervention condition – rather than a trial arm – is a relatively new design. SW-CRTs have …

ORTH.Ord - An R package for analyzing correlated ordinal outcomes using alternating logistic regressions with orthogonalized residuals

Background and objectives - Marginal models with generalized estimating equations (GEE) are usually recommended for analyzing correlated ordinal outcomes which are commonly seen in a longitudinal study or clustered randomized trial (CRT). …

Maximin optimal cluster randomized designs for assessing treatment effect heterogeneity

Cluster randomized trials (CRTs) are studies where treatment is randomized at the cluster level but outcomes are typically collected at the individual level. When CRTs are employed in pragmatic settings, baseline population characteristics may …

A scoping review described diversity in methods of randomization and reporting of baseline balance in stepped-wedge cluster randomized trials

Objectives - In stepped-wedge cluster randomized trials (SW-CRTs), clusters are randomized not to treatment and control arms but to sequences dictating the times of crossing from control to intervention conditions. Randomization is an essential …

Sequential Sampling in Prospective Observational Studies

Many factors must be taken into account when designing an observational study. Unlike controlled studies, observational studies cannot mitigate the effects of confounding through randomization and such factors should be incorporated into both the …

Reasons for undergoing amyloid imaging among cognitively unimpaired older adults

Preclinical Alzheimer's disease (AD) clinical trials screen cognitively unimpaired older adults for biomarker criteria and disclose their results. We examined whether participants in the Anti-Amyloid Treatment in Asymptomatic Alzheimer’s disease …