According to data from the HIRA’s Health and Medical Big Data Open Portal, 92,124 patients (178.1 patients per 100,000 persons) underwent IVI in 2023, compared to 26,005 patients (51.2 patients per 100,000 persons) in 2014. From 2014 to 2023, the number of patients undergoing IVI demonstrated a steady increase (Table 1). The total number of IVI was 54,026 in 2014, rising significantly to 291,784 in 2023, reflecting a steep upward trend over this period (Table 2). In all observed years, both the number of male patients receiving IVI and the total number of procedures performed in male patients were higher than those in female patients (Figs. 1, 2).

In terms of healthcare expenditure trends, total medical costs associated with IVI was 44,507,625 PPP dollars in 2023, compared with 5,426,462 PPP dollars in 2014. The overall medical expenses of IVI have consistently increased since 2014 (Table 3 and Fig. 3).

Analysis by 10-year age intervals revealed that patients in their 70s underwent the most IVI procedures, followed by those in their 60s (Table 1 and Fig. 4). An increasing trend was observed in the number of patients undergoing IVI per 100,000 persons with advancing age, particularly from the 40s to the 70s (Table 1).

From 2014 to 2019, tertiary healthcare facilities recorded the highest number of IVI each year. Secondary healthcare facilities had the next highest numbers and recorded the highest number of IVI performed from 2019 to 2022. The number of IVI performed at primary healthcare facilities steadily increased from 2014, with primary healthcare facilities recording the second highest numbers since 2022 (Fig. 5). The percentage of total IVIs performed at primary healthcare facilities increased from 20% in 2014 to 33% in 2023.

In this study, we examined the trends in the number of patients undergoing IVI and the distribution across different types of healthcare institutions in Korea from 2014 to 2023. During this period, both the number of patients receiving IVI and the total number of IVI gradually increased, especially at primary healthcare facilities.

This may be primarily attributed to the growing prevalence of diseases requiring IVI, such as AMD, DME, and RVO [6-8]. In conditions requiring IVI, treatment typically necessitates regular, ongoing injections rather than achieving complete remission, leading to a cumulative increase in the number of patients [9,10]. Moreover, the development of novel therapeutics such as brolucizumab and faricimab has expanded the range of available treatment options, leading to an increase in the number of IVIs [11,12].

The growing number of approved biosimilars may have also played a role in this increasing trend. ranibizumab biosimilars such as SB-11 (Amelivu, Samsung Bioepis) and CKD-701 (LucenBS, Chong Kun Dang Pharmaceutical) have been approved by the Korean Ministry of Food and Drug Safety (MFDS) and have been in clinical use since 2022. Additionally, aflibercept biosimilars, such as SB-15 (Afilivu, Celltrion) and CT-P42 (Eydenzelt, Celltrion), received MFDS approval in 2024 and is currently available in the South Korean market [13]. The introduction of these biosimilar agents is expected to reduce the economic burden on patients, which may potentially lead to an increase in the overall number of IVIs in the future.

This trend can be also explained by changes in healthcare policy. In the case of AMD, the number of reimbursable anti-VEGF injections was limited to 10 in January 2013 but was increased to 14 in November 2014. By December 2017, the restriction on the number of IVI was removed entirely, and this change may have led to the increase in IVI [14]. Additionally, the approval of treat-and-extend protocols under insurance coverage has allowed for a further increase in the frequency of injections. As the number of patients receiving IVI and the total number of IVI gradually increased, the overall healthcare expenditures are also on the rise (Fig. 3).

Male patients had a higher incidence of IVI, both in terms of the number of individuals receiving the procedure and the total number of injections performed, compared to female patients in all observed years. This may be attributed to the positive association between AMD and men [7]. Furthermore, Arthur et al. [15] reported that the pathological changes in diabetic macular edema result in greater retinal thickening in men than in women, which aligns with our study’s finding that IVI procedure was more frequently administered in male patients.

The age group with the highest number of patients undergoing IVI was those in their 70s, followed by those in their 60s. This trend is likely because conditions that require IVI, such as AMD and RVO, are prevalent in these age groups [6,8]. Considering the demographics of these conditions, it is logical that the number of examinations is highest among older age groups.

Regarding the distribution of healthcare facilities performing IVI, we observed an increasing number of patients undergoing this procedure in primary care facilities over the years. This trend is likely due to the simplicity of performing IVI in local clinics and increased accessibility of diagnostic equipment, such as optical coherence tomography and fluorescein angiography in local clinics [16]. Recently, the availability of biosimilars such as ranibizumab and aflibercept has expanded treatment options at a more affordable cost. Consequently, IVIs are now more commonly administered in local clinics.

The major limitation of this study is the absence of specific diagnostic information for which IVI was performed, due to the lack of clinical data in the dataset. Therefore, disease-specific analyses were not available due to this limitation. Further studies that include diagnostic codes and information on specific anti-VEGF agents may provide more clinically meaningful results. Secondly, since bevacizumab is not a reimbursed medication in South Korea, its procedure code was not included in claims data, resulting in an underestimation of the actual number of injections administered. However, a retrospective study from a secondary healthcare institution in Korea reported that, over a 6-month period, 2,929 intravitreal anti-VEGF injections were administered, of which 693 (23.7%) were bevacizumab [17]. Considering that reimbursement criteria in South Korea differ by disease and are dependent on factors such as visual acuity or optical coherence tomography findings, it is likely that bevacizumab was administered in cases not meeting the reimbursement criteria. As tertiary hospitals may utilize a greater proportion of reimbursed agents such as ranibizumab or aflibercept, it can be inferred that bevacizumab accounts for approximately 20% to 30% of all IVIs in clinical practice. Despite these limitations, this study holds clinical significance as it utilizes objective and reliable big data and is the first comprehensive analysis of trends in IVI practices in South Korea.

In conclusion, over the past decade in Korea, there has been a gradual increase in both the number of patients undergoing IVI and number of procedures performed. The highest number of IVI were conducted on patients in their 70s, and healthcare costs have increased annually. Moreover, an increasing number of IVIs performed in primary healthcare facilities was observed. To the best of our knowledge, this is the first nationwide study to analyze annual trends in IVI procedures in South Korea. The results of this study offer meaningful insights by identifying distinct patterns in IVI utilization, which may reflect broader demographic and institutional changes. Furthermore, by analyzing the increase in total medical expenditure related to IVIs, this study provides important foundational data to inform future discussions on healthcare policy, insurance coverage, and infrastructure planning for retinal disease management. These results may serve as valuable evidence for the efficient allocation of medical resources, and policy- driven strategies will be required to address the rising patient demand and associated financial burden.