Demographics, health behaviors, and past drug use as predictors of recall accuracy for previous prescription medication use

Drug data for pharmacoepidemiologic studies are often ascertained by self-report, but little research has addressed the factors influencing its accuracy. Stratified random sampling was used to select individuals for a study comparing interview data on past prescription drug use with dispensation information from the Group Health Cooperative of Puget Sound pharmacy database. The strata included age, gender, and recency of use. Recall accuracy and its determinants were evaluated for repetitively used non steroidal anti-inflammatory drugs (NSAIDs), short-term NSAIDs (only a single dispensation), and post-menopausal estrogens. We investigated whether recall accuracy was influenced by education, marital status, race, smoking, alcohol consumption, cumulative drug history, the number of different NSAIDs or estrogens dispensed (both by name and dosage), and the number of dispensations of the drug in question. For repetitively used NSAIDs, recall accuracy was positively associated with the number of NSAID dispensations (the odds of recall were 1.7 [95% confidence interval {CL}: 1.3-2.2] times greater for each additional four dispensations of the NSAID), the total number of drugs dispensed, and the number of different NSAIDs dispensed. For estrogen and short-term NSAID use, only higher educational attainment improved recall accuracy: the odds of recall were 4.1 (95% CI: 1.4-11.7) and 2.1 (95% CI: 1.0-4.7) times greater for those with some college compared with those with only a high school degree, respectively. This study demonstrates that predictors of recall accuracy for previous medication use differ by the type of drug and the repetitiveness of its use. (C) 1997 Elsevier Science Inc.