Adherence to Topical Medications for Chronic Rhinosinusitis: Medication Posession Ratio and Description of Adherence Barriers

Rationale: Topical medication is a cornerstone of therapy for chronic rhinosinusitis (CRS) and adherence to these medication regimens is not well described in the literature. Understanding topical medication adherence will help guide further efforts at medical management of CRS.

Methods: Patients with physician-diagnosed CRS on topical medications other than saline alone were recruited from an Allergy Clinic. Claims data were obtained from patient pharmacies for the 6 months prior to enrollment and medication possession ratio (MPR) was calculated. A telephone survey was conducted to assess barriers to adherence using an adaptation of the Brief Medication Questionnaire (BMQ). Patients were defined as non-adherent if they self-reported missed doses for one or more days in the week prior to survey.

Results: Thirteen patients, age 35 to 77, were enrolled. Based on data obtained from the BMQ, 61.5% were non-adherent to their medications in the past week. The mean 6-month MPR; however, based on pharmacy refill data, was 81.5%. Three of the thirteen patients were unsure whether the medication was effective indicating a belief barrier. Approximately half of patients were positive for recall barrier; most patients with recall barriers reported the medication as inconvenient to use or time-intensive to prepare. Access barriers were present in five patients with reasons including expense and inability of the preferred pharmacy to provide the specific medication.

Conclusions: Adherence to topical medications for CRS is low. Attempting to identify and decrease belief, recall, and access barriers is crucial for management of CRS.