Adherence to Intravitreal Anti-Vascular Endothelial Growth Factor (Anti-VEGF) Drugs in Diabetic Macular Edema in an Egyptian Population: A Health Belief Model.

Purpose: To determine the factors that influence the adherence to follow-up and injections in patients with diabetic macular edema (DME) utilizing a health belief model (HBM) as a theoretical framework, and using demographic variables and knowledge about DME as factors that influence individual perceptions.

Material And Methods: A structured questionnaire was developed utilizing the six domains of HBM and using knowledge and other demographics as modifying variables. The questionnaire was checked for validity and reliability, and then used to collect data from patients with DME who were candidates for intravitreal injections according to pro-re-nata regimen, and completed one year after the first injection. Univariate and multivariable analysis was performed to identify factors associated with poor adherence.

Results: Of all 343 included patients (168 women and 175 men; mean [SD] age, 58[10] years, 71 (20.7 %) patients dropped visits and/or injections during the first year of treatment. Mean number of dropped injections was 1.32 ± 0.65 (range 1-5 injections). Factors associated with non-adherence were unilaterality of the injection (p < 0.001), absence of funding (p = 0.002), higher perceived barriers (p = 0.011), lower perceived benefits (p = 0.015), lower self-efficacy (p = 0.023), and lower perceived susceptibility (p = 0.029). In multivariable logistic regression model, the final goodness of fit with the data of the model was high (χ/df = 1.81, p < 0.001).

Conclusions: Funding and psychological burden are the main controllable factors for compliance to anti-VEGF therapy in DME. Identifying reasons for non-adherence could contribute to a better outcome.