Abstract
Background: :
While up to 80% of glaucoma patients do not use glaucoma medications as directed, published levels of non–compliance vary greatly. This raises the possibility of regional and practice–specific determinants.
Purpose: :
To estimate the prevalence of non–compliance and ineffective medication administration in the treatment of glaucoma and to investigate possible risk factors for non–compliance.
Methods: :
In the first stage of this planned multi–centered pan–Canadian clinical investigation, data were obtained from two tertiary glaucoma practices. Data concerning use of medications was obtained using a validated questionnaire. Non–compliance was defined as missing at least one drop per week or using incorrect medications or dosage. Medication instillation technique was assessed in all subjects by direct observation. A series of predictor variables were assessed for their impact on compliance and effective medication administration.
Results: :
80 subjects on chronic glaucoma therapy without recent surgery were enrolled in the study. 2.5% (95% CI: 0.3–9%) of subjects failed to deliver medication to the eye. However, 49% (95% CI: 37–60%) contaminated the bottle tip while administering medication. 24% (95% CI: 15–35%) of subjects had been shown how to administer drops by their pharmacist. Overall, 33% (95% CI: 21–46%) of subjects reported non–compliance. Univariate analysis showed that men were more likely to report non–compliance (OR=3.0; 95% CI: 1.1–8.0). This relationship remained significant in multivariate logistic regression. Of note, age, severity of visual field loss, disease stability and number of medications were not associated with non–compliance.
Conclusions: :
Almost half of the study patients contaminated their medication bottles during drop administration. This may be of special concern in eyes predisposed to serious infection such as those with filtering blebs. Only a minority of patients were ever shown how to use ophthalmic medications by their pharmacist suggesting that physicians should not rely upon this service. Finally, non–compliance was very common in the study population and is a valid concern for physicians treating patients with glaucoma.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence