Doctors who used the system overprescribed certain medications only half as often as those who did not use it.

Studies have shown that this type of technology works to limit possible mistakes in a hospital setting, but this is the first to show that it is successful in an emergency department as well.

Although the study did not test whether reducing overprescribing had any effect on patient health, "renal adjustment is pretty crucial to at least some important medicines," Dr. Paul Dexter, the Chief Medical Information Officer at Wishard Health Services in Indianapolis and one of the study's authors, told Reuters Health. "It is useful to know that clinical decision support might be able to help reduce inappropriate ordering."

The computerized system, one of a type of decision-support system that is becoming more popular in U.S. hospitals, estimates a patient's creatinine clearance. Based on the level of kidney function, the system sets a threshold dose for a medication that emergency doctors would prescribe. If a doctor tries to prescribe more medication than is suggested, the system alerts the doctor, who can then accept or reject the system's recommendation.

In the study, published online in the Annals of Emergency Medicine, researchers randomly assigned 42 doctors at Wishard's emergency department to two groups: one that used the support system when prescribing certain frequently used medications and one that didn't.

Over two years, emergency doctors saw 6,015 patients with renal insufficiency. The computerized system had enough information about slightly less than half of them to determine their creatinine clearance. A total of 113 of those patients had creatinine clearance that showed doctors should adjust their medication dose.

Among the prescriptions written for those patients, doctors not using the technology prescribed more medication than was recommended 74% of the time. This was cut to 43%, a significant reduction, when doctors used the system.

Doctors were more likely to overprescribe less-used medications compared to common medications. They also overprescribed to patients 65 and older more frequently than to younger patients.

The 113 patients were only 4% of those whose creatinine clearance could be evaluated, suggesting it is not that common for patients to need a dosage adjustment. "It's not too surprising that since it comes up so infrequently, for those people where it's important it might be overlooked," Dr. Dexter said. For those rare events, "that's where the computer can be really handy."

The researchers could not be sure why many doctors who were alerted that they had prescribed too much medication did not change their prescriptions. Dr. Dexter said that some of those prescriptions may not have been inappropriate, for example if doctors decided they wanted a higher therapeutic blood level of a medication.

Ultimately, cost will determine whether this tool is feasible, Dr. William Galanter, the Medical Director of Clinical Information Systems at the University of Illinois at Chicago, told Reuters Health. Dr. Dexter estimates that implementing the system for outpatient care costs around $50,000 per doctor.

"If the hospital had a system already, to turn it on in the emergency department really isn't that expensive," Dr. Galanter said. "If you have a hospital that hasn't gone down this road, then it's very expensive."

But if hospitals and emergency departments can afford such systems -- which may be easier with government incentives -- the impact of this technology can go beyond what was shown in this study, said Dr. Galanter, who was not involved with the research.

"People might look at this and say it's not very robust," he said, acknowledging that the system didn't prevent that many errors. "But once it's on, it will continue to prevent errors. It's more robust than you might consider by looking at the results."

By Genevra Pittman

http:/dx.doi.org/10.1016/j.annemergmed.2010.03.025

Ann Emerg Med 2010.

Last Updated: 2010-06-04 10:41:24 -0400 (Reuters Health)

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