Self-report adherence measures in chronic illness: retest reliability and predictive validity.

Area of Science:

• Health outcomes research
• Patient adherence studies
• Chronic disease management

Background:

• Patient self-report is a practical method for assessing medication adherence.
• Optimal use of self-report adherence measures requires further investigation.

Purpose of the Study:

• To evaluate the retest reliability and predictive validity of three distinct self-report adherence measures.
• To assess these measures in patients with common chronic illnesses.

Main Methods:

• Utilized correlation and regression analyses from a randomized controlled trial.
• Included 415 adult patients with chronic conditions like arthritis, asthma, diabetes, and depression.
• Employed self-report adherence measures including pills taken/prescribed (PT/PP) with 1-7 day recall and global adherence reports.

Main Results:

• Contemporaneous PT/PP measures with 1-7 day recall showed strong correlations (>=0.78).
• PT/PP measures correlated moderately with global adherence measures (0.11-0.54).
• PT/PP recall of 3-4 days predicted functional outcomes (HAQ) but not SF-36 scores at 6 months.

Conclusions:

• Self-reported PT/PP and general adherence measures capture different behavioral aspects.
• PT/PP adherence at a single time point may not reflect long-term adherence.
• A 3-4 day recall for PT/PP provides reliable and valid adherence estimates in chronically ill patients, predicting functional outcomes.