The effect of prostaglandin analogs on central corneal thickness of patients with glaucoma or ocular hypertension: a systematic review

Author: Lu Y, Zhong E, Wu J, Cao Y.

Geographical coverage: Ethiopia

Sector: Treatment

Sub-sector: Adherence

Equity focus: Not explicitly stated

Study population: Adult patients with glaucoma

Review type: Effectiveness review

Quantitative synthesis method: Meta-analysis

Qualitative synthesis method: Not applicable

Background:

Glaucoma, a progressive optic neuropathy, is one of the leading causes of preventable blindness. Intraocular pressure (IOP) is the only modifiable risk factor for the development and progression of glaucoma. Raised IOP could cause progressive visual field loss and blindness if left uncontrolled. Adherence to ocular hypotensive medications is vital to prevent optic nerve damage and its consequences.

Objectives:

To systematically summarise the magnitude of glaucoma medication adherence and factors influencing adherence to glaucoma medications among adult glaucoma patients in Ethiopia.

Main findings:

Overall, authors found that less than half of glaucoma patients (49.46%) adhered to the prescribed glaucoma medications. Place of residence, visual acuity, and payment means had statistically significant associations with glaucoma medication adherence.

The review included six studies with a total of 2101 participants for meta-analysis. The studies were published between 2015 and 2023 and included a sample size ranging from 200 to 410 individuals. The magnitude of adherence to glaucoma medication was found to be 49.46% (95% CI [41.27 to 57.66]). The pooled magnitude of adherence for studies that used a tool prepared by the author was found to be 51.13% (95% CI: 38.83 to 63.43) and for studies that used the Morisky medication adherence scale-8 (MMAS-8), it was found to be 46.08% (95% CI 39.32 to 52.85). Urban residents (odds ratio, OR=1.89, 95% CI: 1.29 to 2.49) and those with normal visual acuity (OR=2.82, 95% CI: 0.85 to 4.80) had higher odds of adherence to glaucoma medications. Patients who pay for the medications themselves (OR=0.22, 95% CI: 0.09 to 0.34) were found to have 78% lower odds of adherence than their counterparts.

Methodology:

Authors searched in PubMed, EMBASE, Cochrane, AJOL, SCOPUS, Google Scholar databases. This review included studies (cross-sectional, cohort, and case-control studies) that evaluated glaucoma medication adherence and/or factors influencing adherence to glaucoma medications among adult glaucoma patients in Ethiopia with no restriction on the year of publication of the study. Two reviewers independently searched databases and screened the potentially relevant articles against the eligibility criteria and extracted data of included studies. The study quality was assessed using the Newcastle-Ottawa scale (NOS) by three reviewers independently. Data was analysed using random-effects model meta-analysis. Heterogeneity was assessed using statistics, and meta-regression was conducted by the authors to identify potential sources of heterogeneity. Subgroup analysis was conducted based on the method of adherence ascertainment used by the studies, and publication bias was assessed using a funnel plot and Egger’s test.

Applicability/external validity:

The review authors noted that this study was subjected to recall and desirability biases due to self-reported adherence, which may have led to an overestimation of medication adherence. Additionally, the study represented only 4 out of 12 regions of Ethiopia, therefore, the findings of this review have limited generalisability to the entire country.

Geographic focus:

This study included studies conducted in Ethiopia.

Summary of quality assessment:

Overall, there is medium confidence in the conclusions about the effects of this study. The review authors did not report checking the reference lists of the included studies or contacting the authors/experts, as part of the search strategy.