Telephoning the patient's pharmacy to assess adherence with asthma medications by measuring refill rate for...

To determine whether a prescription refill history obtained by telephoning patients' pharmacies identifies poor adherence with asthma medications more frequently than physician assessment.

The study population consisted of 116 children with persistent asthma who were Medicaid recipients; patients who received medication samples were excluded. During a clinic visit pulmonologists interviewed patients, caretakers, or both and estimated adherence on a checklist. A nurse asked the caretakers where they obtained medications and telephoned 66 identified pharmacies for refill histories. The maximum possible adherence was calculated as the number of doses refilled/number of doses prescribed x 100 for a mean duration of 163 days (range, 63 to 365 days). The accuracy of the refill information was determined from Medicaid reimbursement records.

Information provided by pharmacies was 92% accurate. The mean (95% CI) of maximum potential adherence was 72% (65%,77%) for theophylline, 61% (55%,68%) for inhaled corticosteroids, and 38% (23%,53%) for cromolyn; only cromolyn and theophylline were significantly different. Physicians were able to identify 21 (49%) of 43 patients who refilled

Physicians often were unable to identify patients with very poor adherence. Checking prescription refills is an accurate and practical method of identifying such patients.