Patient medication safety has become a global priority in healthcare, and patients play an important role in promoting their own medication safety.

To develop a Self-assessment Scale for the Ability of Outpatients with Chronic Diseases to Participate in Medication Safety based on the Delphi method and provide objective criteria for assessing and promoting their abilities to participate in medication safety.

A literature review and semi-structured interviews were used to formulate the initial entries of scale for the ability of outpatients with chronic diseases to participate in medication safety. According to the study objectives, 28 experts from Beijing, Shanghai, Guangdong, Tianjin, Zhejiang, and Inner Mongolia participated in two rounds of correspondence using the Delphi method, and were asked to rate their familiarity and judgement basis of the dimensions, and the importance and feasibility of the items were rated using a five-point Likert scale. The first round of expert correspondence was conducted from 30 September to 12 October 2021, and the second round was conducted from 5 to 15 November 2021. Final items of the scale were determined through an expert panel discussion. The questionnaire recovery rate was calculated as a reflection of expert motivation; the degree of authority of the correspondence results was measured using the authority coefficient; the degree of coordination of expert opinions was evaluated using the coefficient of variation and the coordination coefficient Kendall's W. The arithmetic mean of importance and feasibility scores≥3.5 and coefficient of variation<0.25 were used as the initial reference for items selection, the adjustments of the items were decided after the thorough discussions among the members of research team and the expert panel combining with the opinions of experts.

In both rounds of correspondence, 28 questionnaires were sent out and 28 questionnaires were returned, with a positive coefficient of 100% and the expert authority coefficient of 0.877. The expert coordination coefficient Kendall's W of the importance and the feasibility of items in the second round of correspondence increased compared to the first round of correspondence. The mean importance scores of items in the two rounds of the consultation ranged from 3.964 to 4.964 and 4.321 to 5.000, with coefficients of variation from 0.038 to 0.211 and 0 to 0.168. The mean feasibility scores of the items in the two rounds of the consultation ranged from 3.964 to 4.821 and 4.036 to 4.893, with coefficients of variation from 0.081 to 0.265 and 0.064 to 0.186, respectively. The final Self-assessment Scale for the Ability of Outpatients with Chronic Diseases to Participate in Medication Safety was determined after two rounds of expert correspondence and an expert panel discussion, including 4 dimensions of medication knowledge, medication belief, participation in medication decision-making, and medication self-management, with 33 items.

A Self-assessment Scale for the Ability of Outpatients with Chronic Diseases to Participate in Medication Safety containing four dimensions of medication knowledge, medication belief, participation in medication decision-making, and medication self-management, with 33 items, was constructed in the study, which can assess the ability of outpatients with chronic diseases to participate in medication safety and provide a reference for developing appropriate measures to promote patient participation in the medication process and improve medication safety.