Methods used to attribute costs avoided from pharmacist interventions in acute care: A scoping review

Cost-avoidance studies are common in pharmacy practice literature. This scoping review summarizes, critiques, and identifies current limitations of the methods that have been used to determine cost avoidance associated with pharmacists' interventions in acute care settings.

An Embase and MEDLINE search was conducted to identify studies that estimated cost avoidance from pharmacist interventions in acute care settings. We included studies with human participants and articles published in English from July 2010 to January 2021, with the intent of summarizing the evidence most relevant to contemporary practice.

The database search retrieved 129 articles, of which 39 were included. Among these publications, less than half (18 of 39) mentioned whether the researchers assigned a probability for the occurrence of a harmful consequence in the absence of an intervention; thus, a 100% probability of a harmful consequence was assumed. Eleven of the 39 articles identified the specific harm that would occur in the absence of intervention. No clear methods of estimating cost avoidance could be identified for 7 studies. Among all 39 included articles, only 1 attributed both a probability to the potential harm and identified the cost specific to that harm.

Cost-avoidance studies of pharmacists' interventions in acute care settings over the last decade have common flaws and provide estimates that are likely to be inflated. There is a need for guidance on consistent methodology for such investigations for reporting of results and to confirm the validity of their economic implications.