Adherence of patients with diabetic macular oedema to intravitreal injections: a systematic review

Authors: Rose MA, Vukicevic M, Koklanis K.

Geographical coverage: Jordan, Egypt, Europe, the USA

Sector: Diabetic retinopathy, biomedical

Sub-sector: Diabetic macular edema , treatment adherence

Equity focus: Not reported

Study population: Patients with type 1 or type 2 diabetes and diabetic macular oedema in one or both eyes

Review type: Other review

Quantitative synthesis method: Narrative synthesis

Qualitative synthesis method: Not applicable

Background:

Diabetic macular oedema (DMO), a complication of diabetes mellitus, is a common cause of vision impairment that significantly affects individuals’ everyday lives. Treatment options of DMO include vascular endothelial growth factor (VEGF) antagonists and intravitreal injections of corticosteroids. Real-world data evaluating the use of intravitreal anti-VEGF agents shows that DMO patients receive fewer injections than in clinical trials and that DMO patients are more likely than age-related macular degeneration (AMD) patients to cancel/not attend appointments for intravitreal injections. This study explored non-adherence of intravitreal treatment in patients with DMO because poor treatment adherence is associated with increased psychosocial complications, reduced quality of life and reduced treatment effectiveness.

Objectives:

The objective of the review is to study adherence rates of intravitreal treatment for DMO in real-world settings and to identify factors associated with non-adherence to DMO treatment.

Main findings:

The search identified 1,528 citations, of which seven were included in this review (five retrospective cohort studies, one cross-sectional study and one qualitative study). Studies covered patients from European countries, Jordan, Egypt and the USA. The included studies were comprised of treatment naïve patients who were followed for at least 12 months. Six of the seven included studies had low risk of bias, while one was of high risk of bias.

Attendance rates in the studies ranged from 35% to 85%. The rate of missed or delayed attendance varied between 14% and 51%, and at 12-months, 25% of patients were lost to follow-up. Barriers to adherence included patient-related reasons, demographic characteristics and clinical factors, while facilitators to adherence included patient understanding of the disease and treatment. Anti-VEGF treatment adherence in DMO patients was found to be lower than AMD patient adherence to these treatments due to the chronicity of diabetes, the younger age of DMO patients and more specialist appointments for DMO patients which led to less treatment adherence. The authors proposed additional prospective research in this field to enhance our comprehension of adherence in these patients and improve overall patient outcomes. In addition, the authors proposed to standardise the definition of adherence.

Methodology:

The search was conducted in Medline, EMBASE, PsycInfo and CINAHL electronic databases from inception to May 2020 to identify studies conducted on patients with DMO of any stage in one or both eyes. The studies were required to include intravitreal injections for DMO patients, including anti-VEGF, corticosteroids or combination of both, or with intravitreal dexamethasone implant, and report attendance rate to appointments for DMO treatment and/or the factors associated with adherence. Intravitreal implants alone for treatment of DMO were excluded from the study. In addition, clinical trials were excluded and only studies undertaken in real-world settings were included given the known differences between patient utilisation of intravitreal therapy in clinical practice versus clinical trials. No grey literature sources were searched. Two researchers independently checked the search results relevance, extracted the relevant data and assessed the study quality using a modified Critical Appraisal Skills Programme (CASP) checklist. The results were synthesised narratively.

Applicability/external validity:

The authors recognise that the findings related to adherence rates and associated factors exhibit considerable variation. This diversity is likely due to differences in study designs, definitions of key outcomes, treatment plans and patient demographics. Additionally, the lack of a standardised definition for adherence further contributes to this variation. These factors limit the applicability of the study’s findings to other patient populations, clinical settings and countries.

Geographic focus:

Included studies were conducted in Jordan, Egypt, Europe and the USA.

Summary of quality assessment:

Overall, there is low confidence in the conclusions about the effects of this study, as the literature searches were not comprehensive enough to ensure that all potentially relevant studies were included in the review, including those written in languages other than English. Additionally, the authors did not report the results by risk of bias status.