Introduction
Over the last two decades, intravitreal injections (IVIs) have become one of the most common procedures performed in medicine.1 2 This is in large part due to the advent of antivascular endothelial growth factor (VEGF) agents and the large number of exudative retinal pathophysiologies now recognised to be driven by upregulation of VEGF. Injection of these anti-VEGF drugs has become the cornerstone of therapy for a number of exudative retinal disorders, including neovascular age-related macular degeneration (nAMD),3 diabetic macular oedema (DME),4 diabetic retinopathy (DR)5 and retinal venous occlusive disease (RVO).6 Worldwide, the prevalence of each of these conditions ranges in the tens of millions.3 5 6 Accordingly, it is estimated that over 20 million IVIs are administered on an annual basis.1
Several randomised studies have demonstrated the efficacy of anti-VEGF agents for nAMD,7 8 DME,4 DR9–12 and RVO.13 To manage pathological neovascularisation and exudation in these disorders, treatment typically involves repeated anti-VEGF injections over an indefinite time course. Outcomes can thereby depend greatly on patient adherence, which can in turn be influenced by patient experiences and perceptions of satisfaction versus treatment burden. There is, therefore, great interest in optimising patient experiences, towards the goal of maximising adherence.
Studies of the experiences of patients undergoing repeated IVI14 have used long-standing tools such as the macular disease Treatment Satisfaction Questionnaire (MacTSQ),15 designed to examine satisfaction with IVI in the treatment of nAMD. Interestingly, others have reported that patients with high levels of satisfaction measured by MacTSQ continued to identify several burdensome aspects of treatment.14 In one single-centre retrospective study, the most frequent reason patients discontinued treatment was fear of injection.16 Thus, careful examination of the factors underlying patient burden could yield further insight into areas of improvement in the management of exudative retinal disease.
While multiple authors have highlighted the challenging aspects of patient experiences with IVI,17–22 no single quantitative model of patient treatment burden has emerged. In an effort to balance vision benefits against associated burdens of repeated IVI for exudative retinal diseases, the exact frequency of injections needed to maintain optimal clinical outcomes has been the subject of several investigations.4 5 11–13 18 19 23 24 To facilitate this effort, it would be useful for practitioners who manage exudative retinal diseases to understand the magnitude of patient treatment burden associated with repeated IVI.
The current study uses a patient survey to characterise burdensome aspects of repeated IVI and to develop a quantitative measure of patient burden. Herein, we describe the development and psychometric analysis of the Questionnaire to Assess Life Impact of Treatment by Intravitreal Injections (QUALITII). We establish a single score of treatment burden, the IVI Treatment Burden Score (TBS) from this survey. Measurements such as the TBS could inform approaches to optimise patient experiences and adherence for a broad range of retinopathies and/or for comparative analysis of retinal therapeutics.