Abstract
ObjectiveTo develop and validate a questionnaire for the investigation of non-adherence (NA) barriers in patients receiving intravitreal injection (IVT).DesignQuestionnaire development and cross-sectional patient survey combined with a retrospective medical chart review.ParticipantsGerman patients with neovascular age-related macular degeneration (nAMD) or diabetic macular edema (DME) receiving anti-vascular endothelial growth factor (anti-VEGF) treatment via IVT.MethodsThe previously validated (indications: atrial fibrillation, human immunodeficiency virus, chronic inflammatory lung disease) Adherence Barriers Questionnaire (ABQ) was revised according to specifications of IVT, within the framework of an expert panel. The ABQ-IVT, which initially consisted of 24 items formulated as statements (4-point-Likert-scale ranging from “strongly agree” to “strongly disagree”), was applied in a cross-sectional survey. Evaluation of the questionnaire included an assessment of internal consistency and factor analysis. The occurrence of potential barriers in the patient sample was evaluated using descriptive statistics. To identify patient subpopulations, hierarchical cluster analysis was performed using ABQ-IVT answers as predictors. Due to difficulties in capturing NA as an external criterion, the evaluation of the questionnaire was limited to its internal validity and reliability.Main outcome measuresPatients’ answers to the ABQ-IVT questionnaire and interviews.ResultsOf 253 patients, 234 (92%) were able to complete the ABQ-IVT questionnaire. Within the reliability analysis, the ABQ-IVT was reduced to 17 items. The condensed questionnaire demonstrated good internal consistency (Cronbach’s alpha = 0.78), and factor analysis showed no evidence for subscales of the questionnaire. Nearly half of the patients (49%) reported being affected by at least three different barriers. On average, a patient was affected by 3.1 barriers. The most frequently reported barriers were “Challenge due to time commitment of physician visits” (45% of the patients), “Depression” (29%) and “Travel and opportunity costs” (27%). Cluster analysis identified six patient subpopulations, each affected by different sets of barriers and differed regarding their patient characteristics.ConclusionsThe ABQ-IVT is a practical and reliable instrument for identifying patient-specific barriers to IVT treatment adherence. In practice, the questionnaire may be useful in assessing whether individual patients are at higher risk of NA due to specific adherence barriers. Aside from better awareness, this allows earlier interventions, though these still need to be validated. Patient subpopulations face different barriers and may, therefore, need distinct preventative care.
Highlights
Anti-vascular endothelial growth factor therapy currently represents the treatment standard for neovascular age-related macular degeneration and diabetic macular edema (DME) [1,2,3]
Many randomized controlled clinical trials have shown the beneficial effect of intravitreal anti-Vascular endothelial growth factor (VEGF) therapy (IVT) regarding the improvement and maintenance of visual acuity (VA) in patients affected by DME or neovascular age-related macular degeneration (nAMD) [4,5,6,7,8]
In view of the invasive character of intravitreal therapy, there is the peculiarity that the extent of non-adherence can be exactly determined, as it is usually known to the ophthalmologists how often the active substance was administered
Summary
Anti-vascular endothelial growth factor (anti-VEGF) therapy currently represents the treatment standard for neovascular age-related macular degeneration (nAMD) and diabetic macular edema (DME) [1,2,3]. Real-world studies generally fail to reproduce these results, reporting stabilization or slight improvement of VA maintained only for shorter periods of time [9,10,11]. In these studies, more frequent physician visits and intravitreal injections were associated with greater effectiveness of IVT. Therapy adherence can be distinguished from non-persistence, where the treatment or monitoring is stopped or omitted for a longer period of time. As adherence largely affects outcomes, and current methods for improving adherence of patients with chronic health problems are not effective enough to realize the full potential benefit of the respective therapies, ways to improve patients’ adherence are urgently needed [17]. There is no reliable measure that can detect barriers to IVT adherence in everyday clinical practice
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