Adverse Drug Reactions in Hospitalized Patients: A Critique of a Meta-analysis

Marion Kvasz, MD, MPH; I. Elaine Allen, PhD; Matthew J. Gordon, BA; Eric Y. Ro, BA; Rhonda Estok, RN; Ingram Olkin, PhD; and Susan D. Ross, MD, FRCPC

In This Article

Study Selection

To be included in the critique, studies had to meet all inclusion criteria reported in the published meta-analysis. These criteria included English language reports of any study reporting prospective monitoring of ADRs or adverse drug events (ADEs) in patients admitted to the hospital or in the hospital. ADEs were defined as "any injury resulting from administration of a drug" and do not necessarily exclude events that are preventable. Studies with retrospective monitoring of events were excluded, as were studies in which patients were selected for particular conditions or specific drug exposures. Following the original study selection criteria, we sought to also reject studies in which definite and probable ADRs could not be distinguished from possible ADRs. This distinction frequently was very difficult to make at the time of study screening; therefore, we kept such studies for closer examination at the time of data extraction.

All papers that were accepted in the meta-analysis were retrieved and reviewed, even if MetaWorks did not identify or reject some of the papers as a result of its search. Likewise, full papers were retrieved for studies rejected in the meta-analysis if the corresponding abstracts were not identified through our search or if MetaWorks would have accepted such papers on the basis of our review of abstracts.

Non-US studies were also included and retrieved by MetaWorks, if otherwise eligible, because in the published meta-analysis the authors did not initially exclude non-US studies. Since in the course of their analysis, the meta-analysis authors decided subsequently to exclude these studies, we too set them aside.

Two levels of study screening were used. Initially, abstracts of all citations were downloaded and printed at MetaWorks. All abstracts that did not show an obvious reason for rejection were retrieved for further screening. Final eligibility was independently determined by two investigators who resolved differences at a consensus conference.