Letters Section Editor: Stephen J. Lurie,
MD, PhD, Senior Editor.
To the Editor: Dr Gurwitz and colleagues1 reported that adverse drug events are common among
older persons in the ambulatory clinical setting, and that the more serious
adverse drug events also were more likely to be preventable. However, I am
concerned about their conclusion that most of these events were causally related
to drug effects. The authors indicated that this causality was based on "the
temporal relation between drug exposure and the event, as well as whether
the event reflected a known effect of the drug," and state that this method
"has been used in numerous prior studies." Nonetheless, this method is an
insufficient basis for determining a drug effect because it does not account
for the background rate of the events in patients not taking the drug.
Palmer RH. Adverse Drug Effects in Ambulatory Elderly Patients—Reply. JAMA. 2003;289(24):3238. doi:10.1001/jama.289.24.3238-a