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Drug-related hospitalizations: A preventable problem?
Reductions are possible with right strategy
Studies in the U.S. estimate that adverse drug events account for up to 28% of emergency department visits and 25% of ambulatory care encounters and that up to 70% of these visits are preventable. A Canadian study reported in Pharmacotherapy says that in addition to the morbidity and mortality associated with adverse drug events, the resulting costs contribute to the overall pressures on the healthcare system.1
In Canada, the report says, there has been limited research to characterize the impact of drug-related hospitalizations. There was a 2004 Canadian Adverse Events Study that evaluated adverse events in Canadian hospitals, but it was not designed to evaluate adverse drug events resulting in hospitalization. Also, most research has been retrospective and resulted in inherent methodologic limitations, such as possible underestimation of the problem.
"In this era of increased attention to improved patient safety coupled with continuing budget restraints, accurate characterization of drug-related hospitalization is an important step toward reducing the potentially significant burden such problems place on our healthcare system," the report said. "The purpose of this study was to prospectively evaluate the frequency, severity, preventability, and classification of adverse drug events resulting in hospitalization in an internal medicine service of a large tertiary care hospital, and to identify any patient, prescriber, drug, and system factors associated with these events."
Study author Peter Zed, PharmD., at Vancouver General Hospital in Vancouver, British Columbia, tells Drug Formulary Review that as patient safety has evolved, there have remained unanswered questions about drug-related epidemiology and it is important to have a clear picture of the impact of patients presenting with drug-related causes. He says the study clearly showed it is possible to have an impact in reducing drug adverse events. Adverse drug events are defined as unfavorable medical events related to drug therapy.
72% deemed preventable
The study looked at consecutive adult patients admitted to the Vancouver General Hospital internal medicine units during a pre-defined 12-week period from January 10 to April 4, 2005. Primary study outcomes were the frequency, severity, preventability, and classification of drug-related hospitalizations.
During the 12-week study period, 739 patients were admitted to the internal medicine service at Vancouver General Hospital and 565 patients were included in the final analysis. Drug-related hospitalizations occurred in 136 patients (24.1%), of which 98 (72.1%) were deemed preventable. Adverse drug reactions, improper drug selection, and non-compliance were the most common classifications of drug-related hospitalization.
Overall, a total of 167 drugs were implicated in the 136 drug-related hospitalizations. In 105 of the 136 hospitalizations, a single drug was associated with hospitalization, whereas in 31 hospitalizations, several drugs were implicated. The most common drug classes associated with drug-related hospitalization were cardiovascular agents (27.5%), antibiotics (23.4%), nonsteroidal anti-inflammatory drugs (13.2%), central nervous system agents (7.8%), anticoagulants (5.4%), and hypoglycemic agents (4.8%). The most common agents associated with drug-related hospitalizations were aspirin (14%), furosemide (7.4%), ciprofloxacin (7.4%), warfarin (6.6%), ramipril (6.6%), and spironolacatone (5.9%).
Zed says analysis shows the occurrence of drug-related hospitalization was independent of age, sex, number of prescription drugs prescribed, number of OTC drugs taken, use of complementary and alternative medicine, impaired renal function, use of a compliance aid, use of more than one pharmacy, use of a regular family physician, and use of more than one prescriber.
Although 83.8% of patient outcomes associated with drug-related hospitalization were moderate in severity, 7.4% were considered severe, and 0.7% resulted in death.
[Editor's note: For more information contact Mr. Zed at firstname.lastname@example.org.]