Trends of self-reported non-adherence among type 2 diabetes medication users in the United States across three years using the self-reported Medication Adherence Reasons Scale

•The high prevalence of T2D makes it important to know the rates and the reasons for non-adherence with T2D medications.•The data for this study was from the 2017 to 2019 national panels of US adults.•Medication Adherence Reasons Scale was used to measure the medication non-adherence.•The medication non-adherence rate was 25% in 2017, 21% in 2018, and 27% in 2019.•The most common reason for non-adherence across all three years was simply missing the medicine.•The topmost reason for missing medicine for more days in the past week was not knowing how to take medicine.