A trial of automated safety alerts for inpatient digoxin use with computerized physician order entry

Abstract

Objective: Automated clinical decision support (CDS) has shown promise in improving safe medication use. The authors performed a trial of CDS, given both during computerized physician order entry (CPOE) and in response to new laboratory results, comparing the time courses of clinician behaviors related to digoxin use before and after implementation of the alerts.

Design: Alerts were implemented to notify of the potential risk from low electrolyte concentrations or unknown digoxin or electrolyte concentrations during CPOE. Alerts were also generated in response to newly reported hypokalemia and hypomagnesemia in patients given digoxin.

Measurements: Clinician responses to the alerts for six months were compared with responses to similar situations for six months prior to implementation.

Results: During CPOE, checking for unknown serum values increased after implementation compared with control at one hour: 19% vs. 6% for digoxin, 57% vs. 9% for potassium, and 40% vs. 12% for magnesium as well as at 24 hours (p < 0.01 for all comparisons). Electrolyte supplementation increased with newly reported hypokalemia and hypomagnesemia after implementation at one hour: 35% vs. 6% and 49% vs. 5% for potassium and magnesium, respectively, as well as at 24 hours (p < 0.01 for all comparisons). During CPOE, supplementation for hypokalemia was not improved, whereas supplementation for hypomagnesemia improved at one hour (p < 0.05).

Conclusion: Overall, the alerts improved the safe use of digoxin. During CPOE, alerts associated with missing levels were effective. For hypokalemia and hypomagnesemia, the alerts given during CPOE were not as effective as those given at the time of newly reported low electrolytes.

Figure 1.

Compliance curves for unknown digoxin, potassium (K⁺), and magnesium (Mg²⁺) levels. Proportions of patients with orders checking digoxin (○), K⁺ (□), and Mg²⁺ (▵) levels after digoxin was ordered with no recent levels recorded. The x-axis represents time to clinician order for the laboratory level. Clinician response for the control group is represented by the open symbols (○, □, ▵) and dashed lines, and the response for the study group is indicated by the solid symbols (•, ▪, ▴) and solid lines. Responses for the study group were significantly improved for all three alerts (p < 0.001 using the log-rank statistic). Arrows are included for easier identification of each pair of control/study curves.

Figure 2.

Compliance curves for synchronous alerts. Proportion of patients with orders for electrolyte supplementation after digoxin was ordered with a low potassium (K⁺) (□) or magnesium (Mg²⁺) (▵) levels. The x-axis represents time to clinician order for supplementation. Clinician response is indicated for the control groups with open symbols (□, ▵) and dotted lines and for the study group with solid symbols (▪, ▴) and solid lines. The respective control versus study group curves are not statistically different, but the supplementation of Mg²⁺ was higher at one hour using Fisher's exact test.

Figure 3.

Compliance curves for asynchronous alerts. Proportions of patients with orders for electrolyte supplementation after newly reported low potassium (K⁺) (□) or magnesium (Mg²⁺) (▵) levels. The x-axis represents time to clinician order for supplementation. Clinician response is indicated for the control groups with open symbols (□, ▵) and dotted lines and for the study group with solid symbols (▪, ▴) and solid lines. Clinician response significantly improved in both situations with p < 0.0001 using the log-rank statistic.