Prevalence and predictors of inadequate patient medication knowledge

To assess medication knowledge in adult patients and to explore its determinants.

Cross-sectional study. Medication knowledge was the primary outcome and was assessed using a previously validated questionnaire. A multivariate logistic regression analysis was performed to explore the association between medication knowledge and the factors included in the model.

Seven thousand two hundred seventy-eight patients participated in the study. 71.9% (n = 5234) (95% CI: 70.9%-73.0%) of the surveyed patients had an inadequate knowledge of the medication they were taking. The dimensions obtaining the highest level of knowledge were the 'medication use process' and 'therapeutic objective of medication'. The items 'frequency' (75.4%), 'dosage' (74.5%) and 'indication' (70.5%) had the highest percentage of knowledge. Conversely, 'medication safety' represented the dimension with the lowest scores, ranging from 12.6% in the item "contraindications" to 15.3% in the item 'side effects'. The odds ratio (OR) of having an inadequate medication knowledge increased for unskilled workers (OR: 1.33; 85% CI:1.00-1.78; P = 0.050), caregivers (OR:1.46; 95% CI:1.18-1.81; P < 0.001), patients using more than one medication (OR: 1.14; 95% CI: 1.00-1.31; P = 0.050) and patients who did not know the name of the medication they were taking (OR: 2.14, 95% CI: 1.71-2.68 P < 0.001).

Nearly three quarters of the analysed patients had inadequate knowledge regarding the medicines they were taking. Unskilled workers and caregivers were at a higher risk of lacking of medication knowledge. Other factors that correlated with inadequate medication knowledge were the use of more than one drug and not knowing the name of the medication dispensed.