Patients’ knowledge of the indications for their medications – a scoping review

Background: Inadequate medication knowledge may contribute to inappropriate medication use and treatment harms. We aimed to map and synthesise the existing evidence on patients’ knowledge of the indications for their medications. Method: We searched MEDLINE, Embase, CINAHL, PsychInfo and the Cochrane Library for studies that assessed patients’ knowledge of the indications for their medications from inception to June 16, 2022. A pair of reviewers independently screened and extracted data on study characteristics, aims, and methods used to assess and report patients’ knowledge of the indications for their medications. Results: We included 99 studies conducted in 33 countries, published between 1979 and 2021, with 42,377 participants in total (median 126 participants [Interquartile range: 63–338]). Studies were observational (n = 77), experimental (n = 18), or qualitative interviews (n = 4). The exact question used to assess knowledge of the indications was reported in 27 studies and was phrased in 25 different ways. Knowledge of the indications was reported as a proportion of either 1) all participants (n = 65) or 2) the total number of medications used by all patients (n = 13). Sixteen studies used both reporting methods, while five only reported a proportion without specifying the denominator. Fourteen studies in various populations reported the number of participants with correct knowledge of all their medications, ranging from 19% (long-term psychiatric in-patients) to 87% (general practice patients). Conclusion: We did not identify any established scientific standard for assessing patients’ knowledge of the indications for their medications. The wide range of study methodologies and reporting styles observed call for a methodological consensus in this research field. Estimates of correct knowledge varied widely between studies, but whether this was due to differences in study populations or study methodology could not be determined. Furthermore, we did not identify any study investigating whether participants’ knowledge of the indications for their medications was associated with the quality, e.g. appropriateness, of their treatment.