Non-compliance with drug therapy of glaucoma: a review about intervening factors

Methodological quality of the review: Low confidence

Author: Vilela de Castro ANB, Mesquita WA

Geographical coverage: Not specified

Sector: Glaucoma

Sub-sector: Drug therapy non-compliance

Equity focus: None specified

Review type: Other review

Quantitative synthesis method: Narrative/thematic synthesis

Qualitative synthesis method: Not applicable

Background: Glaucoma – which may lead to irreversible blindness – was found in a high proportion of patients who are not compliant with the drug treatment.

Objectives: The objective of this study was to review literature data for the possible intervening factors for non-compliance to therapeutic regime, as well as to find estimated rates for non-compliance.

Main findings: In this review, 199 articles were initially identified. Based on the inclusion and exclusion criteria, 27 articles (25 originals and two reviews) were selected. The following intervening factors were found for non-compliance of glaucoma therapy: sex, age, race, adverse effect, number of instilled doses, number of used eye drops, treatment cost, educational level, inadequate between-dose intervals, co-existing illnesses, forgetfulness and loss of visual field.

In conclusion, this review showed that glaucomatous patients tended to not adequately fulfill their drug treatment. Rates of non-compliance varied from 4.6% to 59%. This variation may be due to the difficulty in defining non-compliance, and by the variance of methodologies used for the determination of the non-compliance rates. Forgetfulness and inadequate between-dose intervals were found to contribute positively to non-compliance to glaucoma therapy.

Other factors such as treatment cost and adverse effect – although having not significantly been associated with non-compliance – have been pointed out as possible barriers to drug adhesion. It was noticed that men tended to adhere less to treatment than women. The authors suggested that further studies for a better evaluation of possible intervening factors for non-compliance to glaucoma drug treatment were required.

Methodology: This systematic review was conducted between January and June 2006. Two databases – PUBMED and the Literature Latin American and Caribbean Health Sciences (LILACS) – were used. The following key words were used: glaucoma, compliance of the patient, noncompliance of the patient, treatment and eye drops. Articles written in English, French, Spanish and Portuguese were included. Articles published between June 1976 and June 2006 were raised.

The review included articles dealing with causes or intervening factors in the compliance to glaucoma drug treatment, and estimated rates of compliance and/or non-compliance to glaucoma drug treatment. Those excluded were: those using invasive methods for evaluation of the compliance; analysing compared anti-glaucomatous effects; approaching exclusively the persistence to glaucoma drug treatment; focusing on the improvement or increase of compliance to glaucoma drug treatment; and having no known authorship. The interest data was collected and presented as text and tables.

Applicability/external validity: Authors did not discuss the applicability/external validity of results.

Geographic focus: The authors did not restrict to the inclusion of studies to specific income settings. However, it’s not clear which specific countries were included in the review.

Summary of quality assessment: The systematic review has the following major limitations: language bias was not avoided as only articles written in English, French, Spanish and Portuguese were included. Reference lists in included articles were not reviewed and authors/experts were not contacted as part of the search strategy. It is not clear from the review how articles were identified, assessed for the quality and how data were extracted. Therefore, there is low confidence in the conclusions about the effects of this study.