Prescriber and pharmacy variation in patient adherence to five medication classes measured using implementation...

Area of Science:

• Health Services Research
• Pharmaceutical Sciences
• Clinical Pharmacy

Background:

• Medication adherence is crucial for managing chronic conditions and achieving desired therapeutic outcomes.
• Understanding the sources of variance in medication adherence is essential for developing effective interventions.
• Previous research has primarily focused on patient-level factors, with less attention paid to prescriber and pharmacy contributions.

Purpose of the Study:

• To quantify the proportion of variance in patient-level medication adherence attributable to prescribers and pharmacies.
• To analyze these contributions across five distinct drug classes: ACE inhibitors, antihyperglycemics, drugs for prostatic hyperplasia, statins, and levothyroxine.

Main Methods:

• Utilized prescription drug claims data from a national pharmacy benefits manager (January 2010-July 2011).
• Included patients and their prescribers covered by Blue Cross Blue Shield of Rhode Island in Massachusetts and Rhode Island.
• Employed mixed-effects models with random intercepts for drug, patient, prescriber, and pharmacy to calculate intraclass correlations and determine variance fractions.

Main Results:

• Overall medication implementation rates ranged from 87% to 91%.
• Prescribers accounted for 12.6% to 16.4% of the explained variance in adherence across the studied drug classes.
• Pharmacies accounted for 9.4% to 20.4% of the explained variance in adherence across the studied drug classes.

Conclusions:

• Both prescriber and pharmacy factors significantly contribute to the explained variance in medication adherence.
• Intervention strategies for chronic conditions should consider targeting prescribers and pharmacies, in addition to patients, for enhanced effectiveness and efficiency.