Measurement of treatment compliance using a medical device for glaucoma patients associated with intraocular pressure control: a survey

OBJECTIVE To identify and characterize treatment compliance profiles of glaucoma patients and evaluate the association with intraocular pressure (IOP). METHODS A computerized device (Travalert((R))) that recorded daily instillation times and eye-drop counts was given for 3 months. Patients were declared compliant when at least 2 drops were instilled per day. Compliance rates were calculated for weekdays and weekends, separately, over 8 consecutive weeks. A principal components analysis (PCA) was followed by an ascendant hierarchical classification (AHC) to identify compliance groups. RESULTS 140 patients were recruited (mean age 65.5 years; 51.8% female) of whom 83.6% had primary open-angle glaucoma with mean IOP 23.9 mmHg before Travalert((R)) use. 60.7% were treated with DuoTrav((R)) (travoprost timolol fixed combination) and 39.3% with travoprost. The PCA identified two axes (compliance and treatment weeks). The AHC identified 3 compliance groups: 'high' (56.6%, approx. 80% compliance), 'medium' (21.2%, approx. 50% compliance), and 'low' (22.1%, approx. 20% compliance). Demographics and glaucoma parameters did not predict low compliance. Final mean IOP was 16.1 mmHg, but higher in the low compliance group (17.7 mmHg, P = 0.02). CONCLUSIONS Compliance measurement by a medical device showed compliance rates <80% by 50% (approx.) of patients, significantly impacting IOP control. No demographic or glaucoma variable was associated with low compliance.