[Validity assessment of self-reported medication use in a pharmacoepidemiologic study by comparison with prescription...

Objectives　Although self-reported questionnaires are widely used to collect information on medication use in epidemiological studies, their validity for studies involving older adults has not been sufficiently assessed. This study evaluated the validity of self-reported medication use using questionnaires in comparison with drug notebooks.Methods　The study enrolled 370 older community dwellers who participated in an aging sub-study survey of the Tsuruoka Metabolomics Cohort Study between April 2019 and March 2021. Medication use was assessed by comparing self-reported questionnaire data with drug notebook records. We analyzed medications used for hypertension, dyslipidemia, myocardial infarction, angina, diabetes, rheumatism, osteoporosis/metabolic bone disease, constipation, anxiety/depression, dementia, asthma, allergy, thrombosis, and thyroid disease. Moreover, gastrointestinal (GI) medications, steroids, and antipyretic analgesics were assessed, and data on injectable medications for osteoporosis/metabolic bone disease was collected. Using drug notebook records, we identified regular medication users by assessing whether they had received oral medication prescriptions covering over 28 days and took the medication within the 90 days preceding the day of their survey. To define medication categories, we used Anatomical Therapeutic Chemical (ATC) classification codes. Sensitivity, specificity, and kappa statistics were calculated for each medication using drug notebooks as standards. Those who did not bring their drug notebooks on the day of the survey were defined as non-medication users.Results　The mean age (standard deviation) of the 370 participants (146 men and 224 women) was 73.3 (4.0) years. The sensitivity and specificity for each medication were as follows: hypertension (0.97, 0.97), dyslipidemia (0.93, 0.98), myocardial infarction (0.24, 0.99), diabetes (0.94, 1.00), rheumatism (1.00, 1.00), osteoporosis/metabolic bone disease (0.82, 0.99), constipation (0.71, 0.98), GI conditions (0.63, 0.97), anxiety/depression (0.36, 1.00), dementia (0.67, 1.00), asthma (0.67, 0.98), allergy (0.57, 0.99), thrombosis (0.88, 0.98), steroids (0.80, 0.99), thyroid disease (1.00, 1.00) and antipyretic analgesics (0.75, 0.96).Conclusions　Although sensitivity and specificity differed by medication categories, the results of our population-based cohort study suggested that self-reported questionnaires on medication use among older adults are valid, especially for medications with high sensitivity (≥ 0.8).