Difference Between Subjective and Objective Drug Adherence in Glaucoma Patients With Relevance to Personality Traits

Abstract

Purpose: : To compare subjective adherence (SA) and objective adherence (OA) in patients using topical anti-glaucoma medication and to discern the pattern of adherence with relevance to personality traits determined by Meier-Briggs type indicator (MBTI).

Methods: : Prospective, cross-sectional, comparative study. An electronic monitoring device (Travalert TM) was employed to objectively determine topical drug adherence. Travoprost (Alcon, Fort Worth, Texas) was prescribed daily for one month to 71 newly confirmed glaucoma patients. SA was asked by questionnaire while OA was assessed by electronic monitoring device. Both were assessed on a five point scale with 5 being the best adherence. Before medication, personality traits were investigated by MBTI. Any difference between SA and OA was determined. Patterns of drug adherence and relevance to personality traits were assessed.

Results: : There was significant correlation between SA and OA (R² = 0.1796). While 42.4% of patients answered to 5 points to subjective questionnaire, only 10.2% showed 5 points on objective findings. Most patients (40.2%) showed 2 points, missing almost one half of their dosing schedule per week. By electronic monitoring, patients with Sensing dichotomy by MBTI were more likely to deviate from SA (p <0.05).OA pattern was analyzed and 43.2% of patients showed high OA in the beginning, which gradually decreased until a week before the next clinic visit when it rose once more. Pattern of drug adherence did not show any differences for any personality dichotomy except for Sensing (p=0.02).Regardless of OA, there was no difference in intraocular pressure (IOP) reduction after the month of study.

Conclusions: : Sensing dichotomy are those that like hard, cold, concrete evidence. This group was more likely to deviate from subjective adherence and also showed improved drug adherence towards the end of the month.Although this study shows no relationship between better drug adherence and better IOP control, this may be a misconception since those on an intensive schedule a few days from their clinic appointment may show masked low IOP which may have been higher during most of the follow up period.Drug adherence is more likely a factor of how we gather information for decision making.

Clinical Trial: : www.clinicaltrials.gov NCT00481494

Keywords: intraocular pressure • clinical (human) or epidemiologic studies: outcomes/complications • quality of life