Self-reported medication nonadherence predicts cholesterol levels over time

Area of Science:

• Clinical Pharmacy
• Health Outcomes Research
• Psychometrics

Background:

• Self-report measures for medication nonadherence are often used across different patient groups without validation.
• Previous validation of a nonadherence measure was in hypertensive patients.

Purpose of the Study:

• To evaluate the predictive validity of a medication nonadherence measure in patients using cholesterol-reducing medications.
• To assess if self-reported nonadherence predicts cholesterol levels.

Main Methods:

• Secondary analysis of data from a randomized trial (n=236) at the Durham Veterans Affairs Medical Center.
• Used cross-lagged panel models and growth curve analysis to examine predictive utility.
• Measured serum cholesterol and self-reported nonadherence at baseline, 6, and 12 months.

Main Results:

• The 3-item nonadherence measure demonstrated reliable scores and fit a single-factor model.
• Medication nonadherence and changes in nonadherence moderately predicted future cholesterol levels (7/9 associations significant).
• Evidence for reverse causation (cholesterol predicting nonadherence) was weaker (3/9 associations significant).

Conclusions:

• The findings support the predictive validity of the self-report medication nonadherence measure.
• The measure is a valid tool for assessing nonadherence in patients taking cholesterol-reducing medications.
• This study provides evidence for adapting nonadherence measures across different clinical populations.