A Systematic Analysis of Reviews Exploring the Scope, Validity, and Reporting of Patient-Reported Outcomes Measures of Medication Adherence in Type 2 Diabetes

Introduction: Non-adherence to medicines is estimated to cost billions to healthcare providers across the US and Europe each year. Addressing medication adherence (MA) can be challenging. Patient-reported outcome measures (PROMs) have been developed to collect self-reported data on MA, among other behaviours. Despite the myriad PROMs available and their widespread implementation in research, there is little commentary or standardization on the way they are reported, or their validity assessed. This review aims to provide a comprehensive analysis of systematic reviews (SRs) that report PROMs of MA with a focus on type 2 diabetes to explore PROM reporting and validity. Materials and Methods: A literature search was conducted using the following databases: PubMed, EMBASE, CINAHL, Cochrane, and Web of Science. SRs reporting on PROMs related to MA behaviour in patients living with type 2 diabetes were included. Any SR published in English prior to December 2021 was included. Abstract and title screening were performed prior to full-text review by two independent researchers with discrepancies managed by a third. Protocols and SRs reporting on paediatric populations were excluded. Results: A total of 19 eligible SRs that included 241 unique PROM studies were captured from the initial 2074 records that were identified. Data were captured across a 30-year scope, with roughly half (47.4%, n=9/19) of the SRs published in the last 5 years. In total, 104 unique PROMs were identified. Inclusion of non-validated PROMs was identified in 63.2% (n=12/19) of the included SRs, and reporting issues were identified in 47.3% of studies (n=114/241). A lower journal impact factor was significantly associated with a higher prevalence of validity issues (r=0.44, p=0.04). Conclusion: There are a broad range of available PROMs; however, they have been reported inconsistently in the literature, often lacking significant evidence with respect to validity criteria. Standardization of reporting and assessments of validity may help to address this.