Patient Prefer Adherence. 2026 May 19;20:602433. doi: 10.2147/PPA.S602433. eCollection 2026.
ABSTRACT
INTRODUCTION: Existing instruments for assessing medication nonadherence lack sufficient insights into the specific barriers to Low-Middle-Income-Countries (LMICs), thus limiting their utility in developing tailored intervention approaches. This cross-sectional scale development and validation study therefore aimed to develop and validate a patient-centered, self-reported scale to identify patients’ medication adherence and barriers relevant to LMICs contexts among people with chronic diseases.
METHODS: This study had three-phases: (i) item development, (ii) content and face validity, and (iii) psychometric analysis. After item development, the items were refined through Item Content Validity Index (I-CVI) assessment and patient pre-testing. The third phase evaluated psychometric properties along with an assessment of agreement with objective clinical indicators (blood pressure and fasting blood glucose) and comparison with the validated scales Medication Adherence Report Scale-5 (MARS-5) and VAS Adherence using 419 patients. Statistical analyses included confirmatory factor analysis (CFA) to determine model fit. We also determined reliability and assessed test-retest reliability.
RESULTS: A final set of 15 items were selected, which were grouped into 4 dimensions: patient, medication, healthcare system, and socioeconomic related-barriers. The CFA showed that the data was fit for the model (χ2=179.477, P<0.001, RMSEA=0.052, CFI=0.961, GFI=0.947). The reliability test showed a good internal consistency (Cronbach’s-α=0.727 and McDonalds- Ω=0.812) and test-retest reliability (correlation coefficient 0.802). The new scale exhibited strong negative correlations with MARS-5 (r=-0.707) and VAS Adherence (r=-0.725), and a moderate negative correlation with clinical measurements (r=-0.632).
CONCLUSION: A psychometrically validated 15-item scale to assess medication adherence and its barriers in patients with chronic disease was developed, offering a reliable, contextually relevant tool that addresses information gaps and supports tailored interventions for improved patient outcomes in LMIC settings.
PMID:42200170 | PMC:PMC13199714 | DOI:10.2147/PPA.S602433
