Background and importance Improving patient’s medication knowledge and consequently medication use is essential for optimal treatment outcomes. As patient knowledge about medication is currently suboptimal, interventions to optimise medication knowledge are necessary. We hypothesise that patient’s own medication (POM) use will improve patient’s medication knowledge.

Aim and objectives To assess the impact of POM use on self-reported medication knowledge of hospitalised patients compared with standard care. Patient’s sense of medication safety, attitude to the provision of information and to inpatient medication use were studied in both standard care and during POM use.

Material and methods In this nationwide intervention study, perceived medication knowledge was assessed with a questionnaire pre and post implementing POM use. The questionnaire assessed perceived medication knowledge (on how to and why to use medication) at admission and discharge, medication safety during hospitalisation, the provision of information during hospitalisation and at discharge, and inpatient medication use. Patients’ answers were categorised into positive and negative/neutral. The proportion of patients with adequate medication knowledge, in the standard care and POM use groups at hospital admission and discharge, were calculated and compared with correction of potential confounders.

Results Among the 731 patients (80.2%) who completed the questionnaire, POM use seemed to be positively associated with self-reported knowledge on how to use medication at discharge (adjusted OR 3.22 (95% CI 2.01 to 5.16)). However, for the knowledge related statement on why medication was used, POM use was not associated. Medication knowledge at admission was the most important predictor of perceived medication knowledge at discharge. The majority perceived POM use safer (52.9% of standard care patients vs 74.0% of POM users; p<0.01), POM users knew better which medicines they still used during hospitalisation (85.8% vs 92.3% respectively; p=0.01) and most patients preferred POM use regardless of having experienced it (68.2% vs 82.2% respectively; p<0.01).

Conclusion and relevance POM use has the ability to positively influence patient’s medication knowledge about how to use medication. Furthermore, it enhances the perception of medication safety, more patients have a positive attitude towards the provision of information and most patients prefer it. Therefore, POM use seems a valuable intervention and more research towards POM use (in combination with self-administration) is recommended.

Conflict of interest Corporate sponsored research or other substantive relationships:

Funding from the Dutch Ministry of Health, Welfare and Sport, the Hague.