A cluster randomized trial evaluating electronic prescribing in an ambulatory care setting

This study was designed as a 65-week, cluster randomized, parallel study.The trial was conducted within ambulatory outpatient clinics in an academic tertiary care centre in Ontario, Canada. The electronic prescribing software for the study is a Canadian electronic prescribing software package which provides physician prescription entry with decision support at the point of care. Using a handheld computer (PDA) the physician selects medications using an error minimising menu-based pick list from a comprehensive drug database, create specific prescription instructions and then transmit the prescription directly and electronically to a participating pharmacy via facsimile or to the physician's printer using local area wireless technology. The unit of allocation and randomization is by 'week', i.e. the system is "on" or "off" according to the randomization scheme and the unit of analysis is the prescription, with adjustment for clustering of patients within practitioners.This paper describes the protocol for a pragmatic cluster randomized trial of point-of-care electronic prescribing, which was specifically designed to overcome the limitations associated with traditional study design.This trial has been registered with clinicaltrials.gov (ID: NCT00252395)A medication error, as defined by the National Coordinating Council for Medication Error Reporting and Prevention (NCCMERP), is a preventable event that may cause or lead to inappropriate medication use or patient harm. Such events may be related to practice, products, procedures, and systems, including prescribing, order communication, product labelling, packaging, nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use [1].Medication errors, adverse drug events (ADEs), and potential adverse drug events impose substantial harms and costs on patients and the health system. The largest study [2] of the prevalence of ADEs and potential ADEs suggests rates of 6.5 ADEs and 5.5 pot