How well does patient self-report predict asthma medication possession? Implications for medication reconciliation and adherence assessment.

Background: Self-report is the most commonly used method for collecting information regarding asthma medication possession and adherence in clinical practice.

Objective: To determine the agreement between self-report and pharmacy claims data for asthma medication possession.

Methods: This is a retrospective study that examined pharmacy claims data 12 months before and after participants completed a structured asthma survey. This study was performed in a sample of health care workers and dependents >17 years old in a large, self-insured Midwestern United States health care center. The main outcome measure was agreement (kappa calculation) between self-report and pharmacy claims data of asthma medication possession.

Results: Self-report of asthma medication use agreed moderately with pharmacy claims data for short-acting albuterol (κ=0.47 ± 0.03), salmeterol (κ=0.79 ± 0.04), and montelukast (κ=0.69 ± 0.03) but only slightly for inhaled corticosteroids (κ=0.18 ± 0.03) and prednisone (κ=0.10 ± 0.03) (n=1050 respondents). Both under self-reporting and over self-reporting were common with inhaled corticosteroids (14.4% and 23.1%, respectively) and varied significantly by specific drug type.

Conclusions: Self-report moderately agrees with asthma medication possession for most adult asthma patients, though the agreement differs considerably between and within asthma medication classes.