Methods

Design
This was a prospective, open, controlled, four period comparative study, with and without CDSS (EES support), performed in the spring of 2019 in one community pharmacy in southern Sweden.
Patients, settings and pharmacists
All patients with at least five prescribed medications dispensed at the Hjärtat Pharmacy in the city of Eslöv were offered an opportunity to participate. The three pharmacists involved all had an MSc in Pharmacy and 25, 15 and 0.5 years of experience.
Intervention and control activities
The study was performed during four weeks in February- March 2019. Study week 1 and 3 were intervention periods, and 2 and 4 controls. In the intervention periods, the pharmacist used the EES support to detect potential DRPs after consent from the patient. All additional prescription dispense support information could be used by the pharmacist during both intervention and control periods to detect potential DRPs. After dispensing a drug in the control group, the patients were offered EES support in the next dispensing.
Documentation template
A separate documentation template was developed and evaluated by the research group, tested in two patients, and was used for documentation in both periods where an actual DRP was identified and documented to be acted upon (appendix 1). The template included basic demographic information, and focused on the type of identified actual DRPs, suggested actions, results of presented/not presented (reason should be given) suggested actions (to patient or prescriber), and also if the DRP was solved or not. Note that only identified potential DRPs that needed action according to the pharmacist were considered an actual patient DRP and documented, as a DRP in the template. No information on patient identity or responsible pharmacist was collected and each patient template only had a reference number. The DRPs were classified as high dose, C/D-interactions, drug duplications, medication inappropriate in children or in the elderly and other. For details on use and evaluation of the form see appendix 1.
Analyses and Statistics
All data were written in MS Excel 2016 (Microsoft Corp, USA). Chi-2 tests were used for all comparisons. We assumed the proportion of patients with at least one DRP to be 50% in the control group and that this would increase to 70% in the EES support group. With a 5%-significance level and power of 80%, we needed 190 patients in total, so we included 100 in each group [16].
Ethical consideration.
This study required no specific ethical approval according to the Malmö University guidelines since the patients were not exposed to any kind of danger and no personal data were collected. The EES is normally used voluntarily by the pharmacists and the patients not receiving the EES support were informed on the possibility to be used, in the next dispensing.