Adverse Drug Reaction Surveillance: Practical Methods for Developing a Successful Monitoring Program

Josephine A. Vitillo, PharmD, BCPS, CGP


December 18, 2000

In This Article

Literature Review

Leape and colleagues[2] reported 3.7% of hospitalized patients experience clinically significant adverse events, with drug complications reported as the most common single type of adverse event (19%). Antibiotics, antitumor agents, and anticoagulants were involved in 16.2%, 15.5%, and 11.2%, of drug-related adverse events, respectively, by medication class. The 3 most common types of drug-related complications included bone marrow suppression, bleeding, and central nervous system effects, occurring in 16.3%, 14.6%, and 14.6%, respectively.

Bates and colleagues[3,4] reported similar rates of ADEs and noted 28% of ADEs were preventable,[3] indicating an opportunity for improvement for healthcare professionals.

Classen and associates[5] evaluated ADEs in hospitalized patients to determine effect on length of stay, cost, and attributable mortality. The authors reported that the occurrence of an ADE was associated with an increased length of stay of 1.91 days and an increased cost of $2262 (P < .001). The increased risk of death among patients having an ADE was 1.88 (P < .001). The most costly ADEs were reported to be fever ($9022), bleeding ($6702), diarrhea ($4631), and cardiac arrhythmia ($4410); these resulted in excess length of stay of 5.49, 4.89, 4.40, and 3.93 days, respectively.

Lazarou and coworkers[6] conducted a meta-analysis of 39 prospective studies from US hospitals to determine the incidence of ADRs in hospitalized patients. Although the results have been criticized,[7,8] the authors reported that ADRs may be the fourth to sixth leading cause of death and that drug-related injuries occur in 6.7% of hospitalized patients, with fatal ADRs occurring in 0.32%.

Bates and colleagues[9] evaluated the costs of ADEs in hospitalized patients at Brigham and Women's Hospital and Massachusetts General Hospital over a 6-month period. Two hundred forty-seven ADEs occurred among 207 admissions, with 60 deemed as being preventable. The additional length of stay for an ADE was 2.2 days, and 4.6 days if the ADE was preventable. The increased cost to treat all ADEs and preventable ADEs was reported to be $2595 and $4685, respectively. If the results of this study represent the rate of ADEs occurring in hospitals across the nation, the IOM report estimates an increase in hospital costs due to preventable ADEs to be $2 billion.[1] The IOM acknowledges that this estimate is conservative, as healthcare is not confined to the hospital but has expanded beyond the institution's walls, thereby expanding the potential for ADEs into the ambulatory care setting.[1]

The findings of the IOM report suggest that 44,000 to 98,000 patients die each year as a result of medical error. More people die annually as a result of medical errors than from motor vehicle accidents (43,458), breast cancer (42,297), or AIDS (16,516).[1]

The IOM report estimates the total national costs, including lost income, lost household production, disability, and healthcare costs, due to preventable ADEs at $17 billion to $29 billion. Healthcare costs comprise over one half of this estimate.[1]

The significant impact ADEs have on morbidity, mortality, and costs cannot be overemphasized, nor should it be ignored. As many ADEs are preventable, resources including time, personnel, and finances, should focus on modification of systems to affect preventable ADEs. A successful ADR monitoring program is one mechanism to positively affect patient quality of care.