Evaluation of a questionnaire to assess compliance with anti-asthma medications

Compliance with anti-asthma medication is essential in controlling symptoms and exacerbations in patients with asthma. Unfortunately, not all patients adhere to their treatment regimen, and it is difficult for clinicians to estimate a patient's compliance, since there is no simple and accurate method currently available to assist in its assessment. The objective of this study was to assess the validity and accuracy of utilizing clinical information regarding a patient's prescription refill frequency, inhaler emptying rate, reported forgetfulness, and short-acting bronchodilator usage to predict daily, anti-inflammatory intake. A questionnaire based on the clinical information described above was administered verbally to asthma patients with varying disease severities. Patient responses were compared to the patient's own pharmacy records. Questions that correlated significantly with pharmacy records were subsequently fit into a multiple regression model. Out of 147 eligible participants, 70 completed the questionnaire and had comprehensive pharmacy data available. There was a significant correlation between daily anti-inflammatory intake as estimated by pharmacy records and daily anti-inflammatory intake as determined by inhaler emptying rate (p<0.05), reported forgetfulness (p<0.05), and short-acting bronchodilator usage (p<0.05). These items were fit into a multiple regression model, which was predictive of daily anti-inflammatory intake as determined by pharmacy records. The sensitivity and specificity of our regression model in detecting non-compliance was 44% and 86%, respectively. We conclude that by inquiring into a patient's inhaler emptying rate, reported forgetfulness, and short-acting bronchodilator usage, a clinician may be able to more accurately estimate a patient's daily intake of anti-inflammatory medication.