Agreement Between Patient Self-report and a Veterans Affairs National Pharmacy Database for Identifying Recent Exposures to Antibiotics

Purpose: The dramatic rise in antibiotic drug resistance among community pathogens has stimulated interest in the epidemiological relationship between antibiotic exposure and drug resistance. In assessing the strength of this relationship, studies are hampered by the lack of data on the accuracy of subject self-report of antibiotic exposure. The authors compared self-report with pharmacy dispensing data to determine the accuracy of self-reported antibiotic exposure.

Methods: The study design was a cross-sectional survey of veterans seen at the Philadelphia Veterans Affairs (VA) Medical Center in 1999 and 2000. Subjects reported exposures to antibiotics, antihypertensive drugs and nonsteroidal anti-inflammatory drugs through a structured telephone interview. The instrument included open-ended questions, condition-specific prompts and drug-specific prompts. Subject responses were linked to a national VA pharmacy database that served as the reference standard for evaluating self-reported exposures.

Results: The authors found that the sensitivity of self-report of antibiotic exposure increased with increasing use of prompts. A comprehensive assessment of antibiotic exposure identified 73% of antibiotic exposures, compared to 73% of antihypertensive drug exposures and 92% of nonsteroidal anti-inflammatory drug exposures.

Conclusions: Assessment of antibiotic exposure appears to be comparable to assessment of other chronic and episodic drugs. Multistep assessment of exposure improves the sensitivity of assessment.