Group-Based Trajectory Models to Evaluate the Association of Lipid Testing and Statin Adherence

Area of Science:

• Cardiovascular Medicine
• Pharmacoeconomics
• Health Services Research

Background:

• Lipid testing post-statin initiation is crucial for monitoring treatment efficacy.
• Inadequate statin response may signal non-adherence, increasing cardiovascular event risk and costs.
• Group-based trajectory modeling identifies distinct medication-taking behaviors.

Purpose of the Study:

• To investigate the association between lipid testing and statin adherence trajectories.
• To analyze adherence patterns in Medicare fee-for-service beneficiaries initiating statin therapy.

Main Methods:

• Retrospective cohort study using Medicare claims data (2006-2015).
• Identified statin use and lipid testing via claims.
• Calculated proportion of days covered to model adherence trajectories.

Main Results:

• Four statin adherence trajectories identified in 138,101 patients: rapid decline (21.53%), gradual decline (10.25%), decline then improve (26.47%), and high adherence (41.75%).
• Lipid testing within 360 days of statin initiation was associated with a lower likelihood of belonging to "rapid decline", "gradual decline", and "decline first then improve later" groups compared to "high adherence".

Conclusions:

• Lipid testing demonstrates a positive association with sustained statin medication use.
• This suggests lipid testing may play a role in promoting adherence to statin therapy.