Alerts to reduce prescribing errors
Two recent interrupted time-series analyses in May 2006 issues of the Archives of Internal Medicine highlight the potential signification contribution of electronic decision support systems to reducing inappropriate or contraindicated prescriptions.
A study by Smith et al focused on reducing contraindicated prescriptions in an elderly outpatient population by introducing alerts in the electronic medical record system; these alerts appeared at the time of prescription entry and were associated with a 22% relative decrease in "nonpreferred" medication orders, particularly with regard to tertiary tricyclic prescriptions.
A study by Feldstein et al examined the utility of EMR-based alerts with or without group academic detailing to reduce the coprescription of selected interacting agents (acetaminophen, nonsteroidal anti-inflammatory medications, fluconazole, metronidazole, and sulfamethoxazole) with warfarin in 15 primary care clinics. The analysis revealed an approximately 15% decrease in coprescription of these agents at 12 months after implementation of the alerts. Authors note that the addition of detailing practices did not affect alert effectiveness.
Though not a medical example, this brief definition of time series analysis from the North Central Regional Educational Laboratory may be useful: "Interrupted time series design: One limitation of pre-post design is that it does not take into account that students were on a particular learning trajectory before the treatment. One way researchers may try to improve on pre-test/post-test design is to determine pre-intervention trends in performance. Researchers may collect information on student or school performance for the several semesters or years prior to the arrival of the intervention. These pre-intervention trends are then compared to the trends in outcomes following the introduction of the technology program. Any differences observed in the trends may be associated with the effectiveness of the intervention." Source