Concordance of severity ratings provided in four drug interaction compendia.
OBJECTIVE
To evaluate the agreement among drug-drug interaction (DDI) compendia as to designation of interactions as having the greatest clinical importance ("major" DDIs).


METHODS
Cross-sectional, one-time evaluation.


METHODS
United States in fall 2001.


METHODS
Not applicable.


METHODS
Major DDIs involving prescription medications likely to be dispensed in the community and ambulatory pharmacy settings were identified as listed in four compendia that provide specific, detailed information about DDIs (Drug Interaction Facts, Drug Interactions: Analysis and Management, Evaluations of Drug Interactions, and the MicroMedex DRUG-REAX program).


METHODS
Level of agreement between DDI compendia as assessed by the intraclass correlation coefficient (ICC).


RESULTS
Overall, 406 major DDIs were listed in one or more of the four compendia. Only 9 (2.2%) of these major DDIs were listed in all four compendia; in fact, the majority of interactions were listed in only one compendium (291 DDIs, 71.7%), despite these interactions being considered of greatest clinical relevance by at least one compendium. The ICC among the compendia was -0.092, indicating low agreement on the classification of major DDIs.


CONCLUSIONS
Little agreement exists among commonly used drug interaction COMPENDIA for DDIs that were classified in fall 2001 as having the highest clinical relevance and importance. A concerted effort to identify DDIs of the highest clinical importance is needed to design effective strategies to avoid and manage them.
Abarca
Jacob
J
Center for Health Outcomes and PharmacoEconomic Research, College of Pharmacy, University of Arizona, Tucson 85721-0207, USA.
Malone
Daniel C
DC
Armstrong
Edward P
EP
Grizzle
Amy J
AJ
Hansten
Philip D
PD
Van Bergen
Robin C
RC
Lipton
Richard B
RB
D016907:Adverse Drug Reaction Reporting Systems; D016208:Databases, Factual; D004347:Drug Interactions; D017723:Drug Utilization Review; D006801:Humans; D012014:Reference Books, Medical; D012720:Severity of Illness Index; D013223:Statistics as Topic