# Long‐term adherence to glucose‐lowering medications in adults with diabetes: A data linkage study

## TL;DR

This study examines how well diabetes patients stick to their glucose-lowering medications over five years and finds that adherence drops after the first year, though some drug classes show better long-term adherence.

## Contribution

The study identifies medication adherence patterns and socio-demographic influences using longitudinal data from a large diabetes cohort.

## Key findings

- Adherence to glucose-lowering medications was highest in the first year and declined in the second year across all drug classes.
- GLP-1 receptor agonists and SGLT2 inhibitors showed improved adherence in prevalent and incident users over five years.
- No socio-demographic subgroup consistently showed higher or lower adherence over time.

## Abstract

To determine the adherence rate in users of each class of glucose‐lowering medication and identify the key socio‐demographic factors influencing adherence.

The 45 and Up Study is an ongoing cohort study of residents aged ≥45 years in New South Wales, Australia. We analysed Pharmaceutical Benefits Scheme records from 2013 to 2019 of the 21 341 study participants who self‐reported having diabetes. Medication adherence was estimated as the proportion of days covered for each 12‐month period for up to the fifth 12‐month period.

A consistent pattern was observed across all drug classes, where the percentage of adherent (proportion of days covered ≥0.8) users was highest in the first 12 months, followed by a drop in the second 12 months. For prevalent users on the same drug class for the full 5‐year period, higher percentages of adherent users compared to the first 12 months were observed for glucagon‐like peptide 1 receptor agonists (77.7% vs 74.2%). For incident users on the same drug class for the full 5‐year period, a higher percentage of adherent users compared to the first 12 months was observed for sodium‐glucose cotransporter 2 inhibitors (84.2% vs 78.4%). Moreover, no socio‐demographic subgroup was consistently more or less adherent to medications.

Initial adherence was good and remained relatively high over time in this cohort. Nevertheless, adherence was still a challenge in some individuals. Practitioners should recognize the possibility of non‐adherence and consider this at each consultation.