If appropriate, a systematic review may include a meta-analysis of the results of a number of different studies.
An individual review may include more than one indirect comparison of two interventions provided separate analyses were undertaken and presented.
Reviews may include trials with three or more arms.
Previous reviews may include more positive appraisals for several reasons.
A medication review may include medication reconciliation, i.e. to identify the most accurate list of medications for a patient.
Patient-level data accessibility was determined in a similar manner, and categorized as available (to external researchers directly or through application and review, may include usage fees); conditionally available (eg, via third party collaborators); or not available/unclear.
Patient-level data: +++Available to external researchers directly or through application and review, may include usage fee; ++Conditional access, eg, via third party collaborators; +Not available to external researchers or access process unclear.
Whereas other reviews may include prevalence estimates from varied populations such as homeless and incarcerated persons, our methods indicate that a thoughtful selection of studies can minimize the variability of some characteristics that typically affect prevalence estimates, improving our understanding of the burden of this disease in the general population.
Patient-level data were available to external researchers either directly or through application and review (which may include usage fees) for 13 registries (27.1%), and 10 (20.8%) had conditional data availability.
Public accessibility to annual reports, publications, or basic data was good for 17 registries and moderate for 22. Patient-level data were available to external researchers either directly or through application and review (which may include usage fees) for 13 of the 48 registries, and were inaccessible or accessibility was unknown for 25.
