Adding value through pharmacy validation: a safety and cost perspective

Prescribing errors (PE) are frequent, cause significant harm to patients and prove costly. Few studies demonstrate the impact of pharmacist interventions. The objectives of this study were to characterize the severity and cost of the potential outcome of PE that pharmacists can prevent and to develop an economic analysis.

We performed a non-randomized, prospective, observational study of all prescriptions made to adult patients admitted to a 1300-bed tertiary teaching hospital in Madrid (Spain) by means of a computerized physician order entry tool combined with a clinical decision support system. We analysed PE intercepted through the pharmacist validation process between January and June 2013. An independent team determined the severity of the potential adverse drug event (ADE) and the probability of causing an ADE (PAE). We estimated the cost avoidance and performed an economic analysis. A kappa statistic was used to verify inter-observer agreement.

484 PE were intercepted: 36.2% of PE were classified as being of minor severity, 59.1% as moderate and 4.7% as serious. The most common type of moderate-serious PE found was excessive dose (30%, 94/309), followed by insufficient dose (20%, 62/309), and omission (19%, 58/309). The most frequent families of drugs involved in moderate-serious PE were antineoplastic agents (22.3%, 69/309) and antimicrobials (17.2%, 53/309). The PAE was higher than 40% in 49% of PE. We estimated a cost avoidance of €291,422 and a return on investment of €1.7 for each €1 spent on a pharmacist's salary. The overall inter-rater agreement for the participants was moderate for severity (κ = 0.57; P <0.005) and strong for the PAE (κ = 0.77; P <0.005).

Pharmacists add important value in preventing PE, and their interventions are financially beneficial for the institution.