Overnight and postcall errors in medication orders

Objective: To compare the error rates in medication orders by physicians who were off call, on overnight call, and postcall. Methods: This was a retrospective review of inpatient medication orders, pharmacy records, and resident physician work schedules in a university-affiliated community teaching hospital with residency programs in emergency medicine, family practice, internal medicine, obstetrics, pediatrics, and surgery. The authors calculated error rates, odds ratios (ORs), and 95% confidence intervals (95% CIs) for physicians during April 2000. Results: In 8,195 medication orders, there were 177 errors (2.16% overall error rate). There was an increased error rate for overnight and postcall orders (2.71%, OR 1.44, 95% CI = 1.06 to 1.95) in comparison to orders written by off-call physicians (1.90%). Error rates were significantly higher on the medical/ surgical wards during the overnight (3.91%, OR 1.89, 95% CI = 1.22 to 2.92) and postcall (3.41%, OR 1.64, 95% CI = 1.10 to 2.43) periods compared with the off-call (2.11%) period, and postgraduate year 1 (PGY1) physicians had a higher overnight error rate (4.23%, OR 2.28, 95% CI = 1.44 to 3.61). Error rates were also higher on the medical/surgical wards compared with critical care units (2.62% vs. 1.22%, OR 2.17, 95% CI = 1.48 to 3.18). The PGY1 physicians had error rates similar to those of the PGY2-5 physicians when off call, but were significantly higher on overnight call (4.23% vs. 0.52%, OR 8.47, 95% CI = 2.00 to 35.82). Conclusions: Medication-ordering error rates were higher for overnight and postcall physicians, particularly on the general medical/ surgical wards, and in PGY1 physicians during the overnight period.