Association between health literacy and medication comprehension; attitudes toward reporting adverse events in adults using over-the-counter medicines

BACKGROUND: Self-medication using over-the-counter (OTC) medicines is one of the effective self-care measures in dealing with daily health problems. Health literacy (HL) is critical to ensuring the appropriate use of OTC medicines. The purpose of this study was to evaluate the association between HL and comprehension of medication package inserts among adults who use OTC medicines. METHODS: We conducted a cross-sectional study using a self-administered questionnaire and interviews at 14 drugstores in the Kanto region in Japan from January to February 2020. The study participants were adults aged 20 years or older who purchased OTC medicines. HL was measured using the 14-item HL scale for Japanese adults (Japanese version of HLS-14), and comprehension of medication package inserts was evaluated using an interview survey (label comprehension study [LCS] form). The association between HL and LCS correct response rate and that between HL and attitude toward reporting adverse drug events (ADEs) were assessed using multiple linear regression and logistic regression analyses, respectively. RESULTS: The analysis included the data of 140 adults, 50 men (35.7%) and 90 women (64.3%), with an average age of 55.2 years. The average HLS-14 score was 51.6, and the overall correct answer rate for reading comprehension was 57.5%. Multiple linear regression analysis revealed that a higher HLS-14 score was associated a higher LCS correct response rate (β = 1.01, p = 0.001). In addition, logistic regression analysis revealed that higher HL was associated with positive attitude towards reporting ADEs to health professionals (adjusted odds ratio = 1.06, p = 0.031). CONCLUSIONS: Adults with higher HL had higher comprehension of OTC package inserts, and higher HL was associated with positive attitude toward reporting ADEs to healthcare professionals. These results indicate that optimal self-medication with OTC medicines requires improving HL among the general public through health education and effective health information provision from pharmacists and registered sales clerks at drug stores. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40545-023-00596-3.