The association of a critical care electronic prescribing system with the quality of patient care provided by clinical pharmacists - a prospective, observational cohort study

•This study used a novel contemporaneous, longitudinal, controlled design.•Contributions with PBP were initially high level and decreased in severity over time.•EP contributions had lower clinical significance and this remained stable over time.•EP improved prescribing quality as measured by pharmacists’ clinical contributions.•EP - Electronic Prescribing; PBP - Paper-Based Prescribing. Despite the strong face validity of electronic prescribing (EP), the empiric data in support of improved patient safety is sparse. The objective of this study was to compare the clinical significance of pharmacist contributions between an established EP and paper-based prescribing (PBP) system in the intensive care unit (ICU) to understand the EP impact on the quality of patient care. We conducted a prospective longitudinal study in two 18-bed ICUs; one with EP and the other, PBP. Pharmacist contributions were analysed over three months. Demographic, clinical and adjunctive intervention data were also collected. A multilevel ordinal logistic regression model was used and patients were followed up for 28 days. The primary outcome was the distribution of clinical significance levels of pharmacist contributions. There were 303 patients admitted to the ICU between April 1st and June 30th 2018. EP was used in 171 patients and PBP in 132 patients. 1658 contributions were analysed. There were 14.9% highly clinically significant contributions with EP compared to 44.6% with PBP. The EP group had lower odds (OR 0.05, 95% CI 0.02–0.12) for a higher clinical significance contribution compared to the PBP group, but this changed over the admission and differed between groups, with decreasing odds of a higher-level clinical contribution for each additional admission day with PBP (OR 0.57, 95%CI 0.42–0.78). This study showed a significant difference in the distribution of pharmacist contributions made over time, with clinical significance levels remaining stable in the EP group at low severity, as opposed to PBP which were initially high and then gradually decreased in severity over time. This contemporaneous controlled study found that the EP system required less significant input both in the severity and frequency of pharmacist contributions to maintain patient safety.