Noncompliance during ophthalmic therapy is a major concern in Palestine. This retrospective cohort study evaluated the compliance among patients with DR, RVO, and AMD, and demonstrated that gender, number of planned injections, cost problems, mobility problems, and physical assistance had an impact on compliance with anti-VEGF therapy. We noticed that the majority of compliant patients were females (58%) and the majority of non-compliant patients were males (56%). Regardless of insurance state, the cost problems affect both compliant and non-compliant patients, most compliant patients had no cost problems (67.4%) and most non-compliant patients had cost problems (56.3%). It was noticed that the majority of compliant patients had no mobility problems (72%) in reaching their care centers to take their injections, but regarding non-compliant patients, the mobility problems (46.9%) didn't affect them significantly. Physical assistance was significantly affecting compliant patients, the most of compliant patients had physical assistance (81.4%), but there was no significant association with non-compliant patients, this could be attributed to sociocultural value in our community. The results also demonstrated that the non-compliant rate increased significantly when the number of planned injections was more than three injections (45.3%) and the compliance rate decreased. In the previous study around (30%) of the patients discontinued the treatment after one or two injections (i.e. incomplete loading dose), which could have led to no improvement in vision and ultimately led to discontinuation or seeking treatment with another doctor (17). According to counseling and insurance state, it's surprising that the majority of non-compliance patients were counseled (82%), and about insurance state, (71.9%) of non-compliance were non-insured, however, the P-Values of these two variables were not significant, (P = 0.429, P = 0.140) respectively. That could be due to the increased efficiency of other variables on compliance. In addition to them, the variables that didn't affect compliance were found in age, education, name of injections, and comorbidities. In our study, the percentage of compliance was (40.2%) and (59.8%) was the percentage of non-compliance patients, a recent report from the United States, which included 2302 patients with proliferative diabetic retinopathy DR and 9007 patients with AMD, showed that around (22%) and (28%) of patients, respectively, were lost to follow-up (18). Another study from Germany, which included 708 patients with AMD, DME, and RVO, reported that (32%), (44%), and (25%) of patients respectively, were noncompliant (19). Similarly, a study from Germany showed that (46%) of patients with DR and (22%) of patients with AMD had at least one therapy break-off (20). A study from Turkey, which evaluated 314 patients, also reported around (40%) noncompliance (21). In contrast, our study non-compliance percentage (58.2%) was higher compared with previous studies. The variations in compliance rates among studies may be attributed to differences in the social and financial circumstances of the patient populations. These variations may be influenced by constraints within our country, particularly related to occupational policies, which affect regular follow-up.
Controlling angiogenesis with anti-VEGF therapy, which is now the standard treatment modality, prevents further deterioration by inhibiting the growth of new vessels and thus stabilizes vision. However, since the underlying pathology continues, anti-VEGF injections need to be continued repeatedly to control angiogenesis. Because clinical practice requires patients to continue attending monthly follow-ups, treatment compliance rates may vary depending on factors that push the limits of patients' compliance with treatment and patients' level of awareness in terms of the disease and its treatment. While anti-VEGF therapy is promising for these patients, the need for repeated intraocular injections makes it difficult to successfully implement. This affects the efficacy and outcomes of treatment.
We acknowledge the following limitations in our study. First, this was a retrospective study and may have a bias with no control over the treatment regimen, and patients may have also received other medications. Second, the reasons for the loss of follow-up were not available for all patients, and every effort was made to contact patients to find the reasons; however, for a few patients, whom we were not able to contact, either the number was changed or the patients did not respond to the call, was excluded from the study. Third, this was a single-center study, so our sample represents a small percent of total patients in Palestine who receive anti-VEGF injections monthly, hence we warrant the readers to carefully generalize these results. The main strength of this study is that it's almost the first study in Palestine about compliance with anti-VEGF. Finally, we recommend the need for more flexible treatment regimens that reduce the burden of treatment, in line with patients' ability and willingness to attend regular anti-VEGF appointments. Further understanding of the comorbidities that present a high risk of non-compliance to treatment is needed to accurately identify at-risk individuals; this emphasizes the need for future researchers to introduce subcategories to allow for more specific data collection regarding the relationship between specific comorbidities and non-adherence and non-persistence to therapy. This recommendation raises awareness about the need for sufficient resource allocation to prevent unnecessary treatment delays under a growing patient pool, and to prevent vision loss.