Purpose
Adherence to glaucoma medications is often poor and has many potential barriers. We identified 11 barriers to adherence that have been repeatedly cited in the literature. We hypothesized that each glaucoma patient would have a unique set of barriers to overcome to achieve optimal adherence. We administered a questionnaire to determine which barriers were most common.
Methods
We surveyed a convenience sample of 185 glaucoma patients. Subjects rated 11 barriers’ importance on a 20-point response scale anchored with “very important” to “not important.” We measured patient reported adherence using a validated instrument, the Morisky Adherence Scale. We assessed socio-demographic characteristics. We conducted descriptive analyses and principal component analysis to identify the structure of the relationships among the adherence variables. Logistic regression was used to predict the association of the principal components with medication adherence.
Results
Each of the eleven barriers was cited as significant by 30%-52% of subjects, who had glaucoma for a mean of 11.5±10.8 years. 26.5% of subjects were non-adherent by self-report. The principal component analysis revealed two factors. The first factor included all of the barriers and had a 48% increased odds of non-adherence, OR=1.48 [95% CI 1.03-2.12, p=0.04], meaning that the more barriers a person reported, the more likely they were to be non-adherent. The second factor revealed that those who had good adherence reported that a poor doctor-patient relationship along with beliefs and knowledge about their disease and medications were important barriers to medication adherence, OR=0.50 [95% CI 0.32-0.80, p = 0.004]. Those who were non-adherent reported that difficulties with their medication schedule, forgetfulness, a lack of confidence, too much other stress, medication side effects, cost and lack of ability to instill the drops were important barriers to taking their medications.
Conclusions
No single barrier to adherence emerged as most important to all glaucoma patients, though barriers did differ for those patients who were and were not adherent. Since poor adherence is associated with disease progression, it is imperative to develop individualized interventions to help glaucoma patients improve their self-management.
Keywords: 464 clinical (human) or epidemiologic studies: risk factor assessment •
462 clinical (human) or epidemiologic studies: outcomes/complications •
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