Personality Traits, Depression, and Objectively Measured Adherence to Once-daily Prostaglandin Analog Medication in Glaucoma

Purpose: To investigate the influence of personality traits, depression, and training on objectively measured adherence to once-daily prostaglandin analog medication. Methods: Adherence was measured with the Travalert Dosing Aid on 58 consecutive, regularly followed-LIP glaucoma patients already on self-administered travoprost. Before the 3-month data-collection period all patients received training on use of the device. Psychologic characteristics were measured using the State-Trait Anxiety Inventory, Eysenck Personality Questionnaire, and Beck Hopeless Scale and Depression Inventory. An adherent day was defined as travoprost instillation at 9 PM +/- 2 hours. Results: Adherence was 77% for the total period. Social desirability was higher than normal (U test, P < 0.0001). Seven patients (12.1%) showed mild-to-moderate depression, which was not significantly associated with decreased adherence (Kruskal-Wallis test, P = 0.071). Severity of glaucoma, number of ocular and systemic medications, satisfaction with the recording device, and socio-economic characteristics had no influence on adherence. Conclusions: Objectively measured adherence to once-daily prostaglandin analog medication was good, and not influenced by treatment characteristics or patient factors including mild-to-moderate depression. The elevated social desirability suggests that self-reported adherence is not a reliable measure of adherence in glaucoma.