Understanding reasons and factors for participation and non-participation to a medication adherence program for patients with diabetic kidney disease in Switzerland: a mixed methods study

Background An interprofessional medication adherence intervention led by pharmacists, combining motivational interviews and feedback with electronic monitor (EM) drug assessment, was offered to all consecutive patients with diabetic kidney disease (DKD) (estimated glomerular filtration rate < 60 mL/min/1.73 m(2)) visiting their nephrologist or endocrinologist. Approximately 73% (202/275) of eligible patients declined to participate, and the factors and reasons for refusal were investigated. Methods Sociodemographic and clinical data of included patients and those who refused were collected retrospectively for those who had previously signed the general consent form. Multivariate logistic regression analysis was performed to identify independent variables associated with non-participation. Patients who refused or accepted the adherence study were invited to participate in semi-structured interviews. Verbatim transcription, thematic analysis, and inductive coding were performed. Results Patients who refused to participate were older (n = 123, mean age 67.7 years, SD:10.4) than those who accepted (n = 57, mean age 64.0 years, SD:10.0, p = 0.027) and the proportion of women was higher among them than among patients who accepted it (30.9% vs 12.3%, p = 0.007). The time from diabetes diagnosis was longer in patients who refused than in those who accepted (median 14.2 years IQR 6.9-22.7 vs. 8.6 years, IQR 4.5-15.9, p = 0.003). Factors associated with an increased risk of non-participation were female sex (OR 3.8, 95% CI 1.4-10.0, p = 0.007) and the time from diabetes diagnosis (OR 1.05, 95% CI 1.01-1.09, p = 0.019). The included patients who were interviewed (n = 14) found the interprofessional intervention useful to improve their medication management, support medication literacy, and motivation. Patients who refused to participate and who were interviewed (n = 16) explained no perceived need, did not agree to use EM, and perceived the study as a burden and shared that the study would have been beneficial if introduced earlier in their therapeutic journey. Other barriers emerged as difficult relationships with healthcare providers, lack of awareness of the pharmacist's role, and negative perception of clinical research. Conclusions Investigating the factors and reasons for participation and non-participation in a study helps tailor intervention designs to the needs of polypharmacy patients. Patients who refused the adherence intervention may not be aware of the benefits of medication management and medication literacy. There is an urgent need to advocate for interprofessional outpatient collaborations to support medication adherence in patients with DKD. Trial registration Clinicaltrials.gov NCT04190251_PANDIA IRIS.