Korean National Health Claims Database Research Articles

Contemporary Patterns and Underlying Causes of Vitrectomy in Pediatric and Adolescent Patients: A Nationwide, Population-Based Analysis

PurposeWe determined the incidence, etiology, and longitudinal trends of vitreoretinal diseases necessitating pars plana vitrectomy (PPV) in the pediatric and adolescent population. DesignNationwide, population-based cohort study. MethodsThis study utilized data extracted from the Korean National Health Claims database spanning from 2009 to 2020. All pediatric and adolescent patients (under 20 years of age) who underwent PPV across the Korean population were included. The cumulative incidence of PPV was estimated from 2009 to 2020, with 2009 to 2011 as the washout period. The annual trends of PPV incidence, the proportion of each etiology, and comorbidity were estimated based on sex and specific age groups. Results: In total, 1,913 patients, including 93 infants, 746 pediatric patients, and 1,084 adolescents, were newly identified as having undergone PPV surgery. The cumulative incidence of PPV surgery per 100,000 individuals was 21.42 (95% CI, 21.41–21.43). The rate of PPV was 2.4 times higher for males than females, and the rate of trauma as a comorbidity was also higher for males than females (13.1% vs. 4.8%). Among males aged 5 years and older, the incidence of PPV nearly halved from 2011 to 2020. Among the primary etiologies, ROP had the highest rate (72%) in infants (under 1 year), while RD was most common (63%) in individuals aged 5–19 years. Myopia was present in 30.3% of patients, and atopic dermatitis was present in 31.8% of all patients. ConclusionThe primary etiologies underlying the need for PPV in the pediatric and adolescent populations vary by sex and age group. The incidence of PPV continues to decline in the adolescent population. Therefore, tailored patient education and age-specific etiological examination are recommended.

Risk of non-thyroidal autoimmune diseases in patients with Graves' disease: a nationwide retrospective cohort study.

Graves' disease (GD) is a major autoimmune thyroid disorder and associated with non-thyroidal autoimmune disease (NTAD). We aimed to investigate the risk of NTAD in patients with GD compared with age- and sex-matched controls and to evaluate whether the risk differs between individuals with or without Graves' ophthalmopathy (GO). This was a retrospective cohort study using data from the Korean National Health Claims database. We included 77 401 patients with GD (2,310 with GO) and 77 401 age- and sex-matched controls. Risk of NTAD were compared between the entire cohort and within the GD cohort. During a mean follow-up period of 9 years, NTAD developed in 12 341 (16.1%) patients in the GD cohort. Risk for systemic lupus erythematosus (SLE) [adjusted hazard ratio (aHR):1.15, 95% confidence interval (CI): 1.02-1.29], vitiligo (aHR: 1.24, 95% CI: 1.10-1.40), and alopecia areata (aHR: 1.11, 95% CI: 1.10-1.40) were higher in the GD cohort than in the control cohort. In the GD cohort, risk for SLE (aHR: 1.60, 95% CI: 1.11-2.33), Sjogren's syndrome (aHR: 1.89, 95% CI: 1.30-2.74), and ankylosing spondylitis (aHR: 1.53, 95% CI: 1.08-2.17) were higher in the GO group than in the non-GO group. This study demonstrated an increased risk of SLE, vitiligo and alopecia areata in patient with GD. In the GD cohort, patients with GO had an increased risk of SLE, Sjogren's syndrome and ankylosing spondylitis. These findings suggest that importance of implementing a strategy for early detection of NTAD based on the presence of GO.

Increased Risk of Optic Neuritis in Patients With Fibromyalgia: Nationwide Population-Based Cohort Study in South Korea

To estimate the risk of incidence of optic neuritis and identify the high-risk group among patients with fibromyalgia (FM). Population-based cohort study. A nationwide, population-based study was conducted using data from the Korean National Health Claims database from 2012 to 2021. This study included all the patients with FM from the entire South Korean population aged 20-79 years (FM group). Moreover, those with pain but not diagnosed with FM were considered as the non-FM group. A cohort was established by classifying it into the FM and non-FM groups during the recruitment period. A log-rank analysis was used to compare the risk of optic neuritis incidence between the FM group and non-FM group. Cox proportional hazards regression analysis was performed to calculate the adjusted hazard ratio (HR). The cohort was analyzed by stratifying according to age and sex. The FM and non-FM groups included 479,892 and 479,892 participants, respectively. The incidence rate of optic neuritis was 35.65/100,000 person-years in the FM group; the HR was significantly higher in the FM group than in the non-FM group (HR 2.11, 95% CI 1.84-2.41; P < .001). The mean interval between the onset of FM and incident optic neuritis was 2.4 ± 1.8 years. The risk increased significantly in men aged 60-79 years (HR 3.37, 95% CI 2.54-4.48) and in women aged 20-39 years (HR 2.07, 95% CI 1.38-3.22). We quantified the risk of optic neuritis through a long-term follow-up, which could contribute to understanding the pathophysiology and estimating the general health care burden associated with FM in a practical setting. Great attention should be paid to its risk in older men and younger women.

Nationwide-incidence and trends of fibromyalgia in South Korea: a population-based study.

Reports of the incidence of fibromyalgia (FM) in Asia are uncommon. Therefore, this study used nationwide representative data to investigate the age- and sex-specific incidence and annual trends of FM in South Korea. This nationwide population-based study used data from the Korean National Health Claims Database. From 2012 to 2021, patients with FM diagnosed according to the ACR 2010 criteria from the entire Korean population aged 20-70years were included in the enrolment database. Age- and sex-specific cumulative and annual incidences were analyzed and incident cases from 2014 to 2021 were included, considering the 2-year washout period. Among the total cohort of 42 million in the entire Korean population, 270,160 had FM during the study period. The incidence in the general population aged 20-70years was 751.25 (95% confidence interval [CI] 751.10-751.40) per 100,000 persons (men: 95% CI 608.45-608.98; women: 95% CI 898.02-898.69). The incidence of FM increased with advancing age, peaking at 50-54years both in men and women. The annual incidence was 88.07 (95% CI 88.02-88.13) in 2014; it increased from 2014 to 2019 and peaked in 2019 (109.20; 95% CI 101.65-101.76). The incidence of FM in South Korea was about twice the global average, with a gradual increase over the study period. These detailed estimates can help with proper planning within the healthcare system.

Increased risk of incident gout in patients with hyperthyroidism: a nationwide retrospective cohort study.

Previous studies have reported that thyroid dysfunction is associated with increased serum uric acid levels; however, the relationship between hyperthyroidism and incidence of clinical manifestations of gout has not been fully investigated. Therefore, this study aimed to longitudinally investigate the risk of gout in patients with hyperthyroidism. This nationwide retrospective cohort study used data from the Korean National Health Claims Database. We included 76,494 patients with hyperthyroidism and 76,542 age- and sex-matched controls. A Cox proportional hazard regression model was used to adjust for potential confounders and estimate the risk of incident gout in patients with hyperthyroidism. During a mean follow-up of 9years, incident gout developed in 3,655 (4.8%) patients with hyperthyroidism and 3251 (4.2%) controls. Hyperthyroidism was significantly associated with increased risk of incident gout [adjusted hazard ratio (HR), 1.12; 95% confidence interval (CI) 1.07-1.18], independent of baseline metabolic profiles. The median time from the diagnosis of hyperthyroidism to the development of gout was 6years. When stratified by age and sex, the risk of gout was still significant in the < 50-year age group (HR: 1.2, 95% CI 1.12-1.29) and males (HR: 1.21, 95% CI 1.12-1.30), but not in the older age group (> 50years) and females. Hyperthyroidism is an important risk factor for incident gout, particularly in younger age groups (< 50years) and males. Our results highlight the importance of continuous screening for gout in patients with hyperthyroidism.

Systemic evaluation of the risk of reoperations in pediatric populations with exotropia and esotropia: nested case–control study

The study aimed to assess the risk of reoperations for strabismus in the pediatric population and to identify high-risk groups. This was a nationwide population-based study that used data from the Korean National Health Claims Database from 2008 to 2020. Two major cohorts were established based on initial strabismus: age-, sex-, and recruitment year-matched controls were randomly selected. Patients aged ≤ 9 years who underwent initial strabismus surgery for exotropia and esotropia were included, resulting in a total of 24,816 patients included to this study. The cumulative incidence of reoperations was 843 per 10,000 persons for exotropia, 1559 per 10,000 persons for esotropia. To assess the significant exposure factors, conditional logistic regression was performed to obtain odds ratio (OR) in each cohort. In patients with exotropia, the OR of reoperations was 4.26 times higher when the initial surgery is performed at younger age (earlier than 3-year-old) and 6.49 times higher when only one eye underwent than two eye. Similarly, in patients with esotropia, younger age (6.57 times) and unilateral surgery (7.20 times) were identified as common factors that increase the risk of reoperations. Based on the findings, special attention is recommended for patients younger than 3 years, especially those performed unilateral surgery as initial intervention in practical settings.

Association of physical activity with total and cause-specific mortality in patients with diabetes: A nationwide population-based cohort study

AimsPhysical inactivity is a modifiable risk factor for cardiovascular disease (CVD) in patients with type 2 diabetes mellitus (T2DM); however, little is known about its association with mortality due to other causes. Herein, we investigated the association between physical activity (PA) and cause-specific mortality in patients with T2DM. MethodsWe analyzed data from the Korean National Health Insurance Service and claims database of adults with T2DM aged >20 years at baseline (n = 2,651,214). Each participant’s PA volume was measured as the metabolic equivalent of tasks (METs)-min per week, and hazard ratios of all-cause and cause-specific mortality relative to PA levels were estimated. ResultsDuring the 7.8 years of follow-up, all-cause, CVD, respiratory, cancer, and other causes of mortality were lowest in patients engaged in vigorous PA. MET-min/week was inversely associated with mortality after adjusting for covariates. The reduction in total and cause-specific mortality was greater in patients aged ≥65 years than in those aged <65 years. ConclusionsIncreasing PA may facilitate a reduction in mortality from various causes, especially among older patients with T2DM. Clinicians should encourage such patients to increase their daily PA levels to reduce their risk of mortality.

Nationwide Incidence of Infantile Cataract Surgery and Risk of Secondary Glaucoma in a Population-based Birth Cohort

To determine the nationwide birth cohort incidence of infantile cataract (IC) surgery and the risk of secondary glaucoma in a Korean population. A population-based, retrospective cohort study. We accessed the Korean National Health Claims database to identify patients with IC who were diagnosed before 1 year of age and who underwent IC surgery among all Koreans born between 2008 and 2018 (n=9,593,003). We estimated IC surgery incidence in a birth cohort. The incidence rates of post-IC surgery glaucoma were estimated per 100 person-years, based on the Poisson distribution. The risk factors for post-IC surgery glaucoma, including ophthalmic and systemic comorbidities, were analyzed by multivariable logistic regression analysis. During the 11-year study period, 692 patients underwent IC surgery. The annual birth cohort incidence of IC surgery in the general population ranged from 5.10 to 9.29 cases per 100,000 individuals. Among patients who had been followed up for longer than 1 year (n=650), 92 (14.2%) developed glaucoma, and its incidence rate was 2.29 (95% confidence interval, 1.86-2.80) per 100 person-years. The mean time from IC surgery to glaucoma development was 4.7 ± 3.5 years. No factors were identified as being associated with post-IC surgery glaucoma risk other than primary or secondary intraocular lens implantation, which reduces the risk (all P < .05). In patients without primary intraocular lens implantation, the risk of glaucoma increased steeply during the first 2 years after IC surgery. This study identified the birth cohort incidence of IC surgery and secondary glaucoma risk in individuals of East Asian ethnicity. These estimates may help to better understand the epidemiologic features and clinical courses of patients with IC.

Surgical Risk Prediction for Nasolacrimal Duct Obstruction in Radioactive Iodine-Treated Thyroid Cancer: A Nationwide Cohort Study.

Background: To estimate the incident risk of surgical intervention for nasolacrimal duct obstruction after radioactive iodine (RAI) treatment and elucidate the high-risk group of patients with thyroid cancer (TC). Methods: This is a nationwide, population-based cohort study using data from the Korean National Health Claims database. Among the entire South Korean population aged between 20 and 80 years from 2007 to 2019, all patients with TC were included. Among all TC patients, a cohort was established by classifying it into the RAI and non-RAI groups according to whether RAI treatment was performed during the recruitment period. A log-rank analysis was used to evaluate the risk of nasolacrimal duct obstruction surgery in the RAI group compared with that in the non-RAI group. The Cox proportional hazards regression analysis was performed to calculate the adjusted hazard ratio (HR). The analysis was performed stratified by the age group, sex, frequency of RAI treatment, and cumulative dose of 131I. Results: Among 55,371 TC patients, who received RAI treatment, 515 (0.93%) underwent nasolacrimal duct obstruction surgeries, and among 56,950 TC patients, who did not receive RAI treatment, 72 (0.13%) underwent the surgeries. The average timing of incident nasolacrimal duct obstruction surgery was 3.8 ± 2.1 years after the first exposure to RAI. The incidence rate of nasolacrimal duct obstruction surgery was 104.04/100,000 person-years in the RAI group. There was a significantly higher risk of nasolacrimal duct obstruction surgery (HR 7.50 [confidence interval, CI: 5.86-9.60], p < 0.001) in the RAI group than in the non-RAI group. The risks significantly increased in the high-dose group (HR 14.15 [CI: 10.88-18.39]) and those younger than 50 years (HR 15.54 [CI: 9.76-24.72]). Conclusion: We quantified the risk of RAI-induced nasolacrimal duct obstruction surgery through a long-term follow-up of 9 years, which may contribute to estimating the general health care burden related to RAI treatment for TC patients in a practical setting. Great attention should be paid to its risk in patients younger than 50 years, especially in those treated with high doses.

Increasing trend in rhegmatogenous retinal detachment in Korea from 2004 to 2015

BackgroundTo determine the 12-year incidence of and trends in rhegmatogenous retinal detachment (RRD) requiring surgery in Korea.MethodsThis was a nationwide, population-based, retrospective study. We identified 53,179 patients with incident RRD requiring surgery using the Korean National Health Claims Database from 2004 to 2015. We estimated the crude incidence rates and age- and sex-standardized incidence rates per 100,000 person-years in each year during the study period. A joinpoint regression analysis was performed to determine the trend.ResultsThe average annual incidence rate was 9.78 (95% CI: 9.70–9.86). Male patients showed an incidence rate (10.68 [95% CI: 10.57–10.80]) 1.20 times that of female patients (8.87 [95% CI: 8.76–8.98]). The incidence showed a bimodal distribution; the highest peak was in the 60–64 year age group (23.77 [95% CI: 23.18–24.35]) and the second peak was in the 20–24 year age group (7.68 [95% CI: 7.41–7.95]). An increasing trend of RRD incidence was observed in the total population throughout the study period using joinpoint analysis (annual percentage change [APC], 2.05; 95% CI: 0.7–3.4). The increasing trend was more prominent among individuals aged under 50 years (APC, 3.44; 95% CI: 2.3–4.6), while among those aged 50 years or above, the increasing incidence was observed only in male patients.ConclusionsIn Korea, the incidence of RRD has increased recently. People in the < 50 year age group accounted for the major part of this significant increase, which is related to the increasing incidence of myopia in the young generation in Asia.

Association of mental disorders and strabismus among South Korean children and adolescents: a nationwide population-based study.

The aim of this study is to determine the association between mental disorders and strabismus in South Korean children and adolescents. Using data from the Korean National Health Claims Database from 2011 to 2017, the prevalence rates of mental illnesses and odds ratio were calculated. Children and adolescents (1-19years) with strabismus and their randomly selected nonstrabismic age- and sex-matched controls (1:1) were enrolled. The odds ratios were adjusted for preterm birth, cerebral palsy, and mental retardation. Subgroup analysis was performed according to sex and the type of strabismus. A total of 327,076 subjects (male, 158,597; female, 168,479) identified as strabismus patients were enrolled. After adjusting for preterm birth, cerebral palsy, and mental retardation, the corrected odds ratio of overall mental illness was 1.10 (95% CI, 1.08-1.12) for the strabismus group compared to the controls: 1.7 (95% CI, 1.62-1.78) for developmental disorder, 1.36 (95% CI, 1.27-1.45) for pervasive developmental disorder (autism), 1.14 (95% CI, 1.10-1.17) for attention-deficit hyperactivity disorder (ADHD), 1.15 (95% CI, 1.05-1.27) for obsessive-compulsive disorder (OCD), 1.08 (95% CI, 1.05-1.11) for pediatric behavioral and emotional disorders, 0.93 (95% CI, 0.88-0.99) for post-traumatic stress disorder (PTSD), and 0.85 (95% CI, 0.82-0.89) for tic disorder. South Korean children and adolescents with strabismus had a higher relative risk for various types of mental disorders such as a developmental disorder, autism, ADHD, and OCD than the controls, whereas they had a relatively lower risk of tic disorder.

Nationwide incidence of myotonic dystrophy type 1 and the status of multi-organ involvement.

This study aimed to investigate the incidence of myotonic dystrophy type 1 (DM1) and the status of multi-organ involvement. This was a nationwide, population-based, cohort study using data from the Korean National Health Claims database. All patients with DM1 from the entire population aged ≤ 80years were included. To identify possible systemic diseases along with DM1, we searched for concurrent codes for systemic diseases. To assess the recent status of systemic evaluation, concurrent codes for various diagnostic and treatment modalities were collected. Cumulative incidence during 2016-2019 was first evaluated then systemic evaluation for those patients was assessed during 2010-2019. A total of 387 patients (47.8% men) during the recent 4-year study period (2016-2019) were diagnosed with DM1. The cumulative incidence in the general population was 0.77 (95% confidence interval: 0.76-0.77) per 100,000 persons. In newly developed incidental cases, cardiac involvement developed in 51.2%, pneumonia in 30.7%, diabetes in 26.9%, brain involvement in 18.1%, cataract in 13.7%, and cancers in 5.4% of total patients. Electrocardiography was performed in 93.8%, Holter in 33.9%, and echocardiography in 31.3% of the total patients for cardiac evaluation. The incidence estimates of DM1 in the Asian population were lower than those of Caucasians. This study provides the real situation of screening and treatment for systemic diseases related to DM1. These detailed estimates could promote an understanding of the current disease status and allow for appropriate planning within the healthcare system.

Pregnancy rates and perinatal outcomes in women with systemic lupus erythematosus: data from the Korean national health claims database.

The pregnancy rate in systemic lupus erythematosus (SLE) is not fully understood and comparisons of adverse pregnancy outcomes (APOs) with SLE versus the general population are limited. This study aimed to estimate the pregnancy rate and APOs in Korean SLE compared to those without SLE. Pregnant women were identified using the ICD-10 codes for delivery and abortion in the Korean national health claims database (2013-2015). APOs were classified as fetal loss, intrauterine growth retardation (IUGR), pre-eclampsia/eclampsia, and gestational diabetes. Annual incidence rates (IRs) of pregnancy and APOs were calculated in women with SLE and the general population without SLE and the two groups were compared using age-adjusted incidence rate ratios (IRRs). Age-stratified IRRs were further analyzed. The annual IRs of pregnancy in SLE were 29.54-30.70 per 1000 persons. The IRRs were lower in women with SLE than in the general population: 0.68 (0.61-0.76), 0.66 (0.60-0.74), and 0.74 (0.66-0.82) in each respective year. The IRRs of fetal loss, IUGR, and pre-eclampsia/eclampsia were 1.30 (1.14-1.49), 4.65 (3.55-6.09), and 3.43 (2.70-4.36), respectively. However, the IRR of gestational diabetes in SLE did not significantly differ from that of women without SLE. Among the APOs, fetal loss, IUGR, and pre-eclampsia/eclampsia showed decreasing tendencies as age increased. Pregnancy rates in SLE were approximately 30% lower than those in the general population. Except for gestational diabetes, fetal loss, IUGR, and pre-eclampsia/eclampsia were higher in SLE and showed a decreasing tendency with age. Key Points • This population-based cohort study showed that pregnancy rates in SLE were approximately 30% lower than those in the general population. • SLE had a 1.3-fold higher rate of fetal loss, more than 4-fold higher IUGR rate, and more than 3-fold pre-eclampsia or eclampsia rate compared with the general population. • Adverse pregnancy outcomes in SLE showed a decreasing tendency with age.

Nationwide population-based incidence and etiologies of pediatric and adult Horner syndrome.

To determine age- and sex-specific incidence and possible etiologies of pediatric and adult Horner syndrome in South Korea. A nationwide, population-based, cohort study using data from the Korean National Health Claims database from 2007 to 2018. All patients with Horner syndrome from the entire Korean population (n = 51,629,512) were included. To find possible causes of Horner syndrome, we searched concurrent codes for systemic diseases, trauma, or surgical procedures. A total of 139 pediatric patients (59.7% male) and 1331 adults (51.0% male) were newly diagnosed as having Horner syndrome. The cumulative incidence was 2.12 (95% CI 2.08-2.17) per 100,000 pediatric population and 2.95 (2.94-2.96) per 100,000 adults. The peak incidence occurred at 0-4years of age in the pediatric population, and at 50-54years in the adult population. A total of 835 (56.8%) patients had underlying conditions or related surgical procedures associated with Horner syndrome. The underlying causes were recognized in 695 (83.2%) patients before the diagnosis of Horner syndrome, in 75 (9.0%) patients at the same time as the Horner syndrome diagnosis, and in 65 (7.8%) patients after the diagnosis of Horner syndrome. There were four cases of Horner syndrome that preceded neuroblastoma diagnosis. The most common tumor related with Horner syndrome was that of the thyroid in the adult population. This study determined the estimated incidence and possible causes of pediatric and adult Horner syndrome. As Horner syndrome with unknown etiologies may harbor serious malignancy, extensive evaluations are required, especially in children.

Twelve-year incidence of retinal vein occlusion and its trend in Korea.

To estimate the 12-year incidence and trends of clinically diagnosed retinal vein occlusion (RVO) in Korea. This is a nationwide population-based retrospective study using the Korean national health claims database from 2002 to 2015. The study consisted of the entire Korean population based on the 2015 Census of Population. We identified patients with incident RVO in 2004-2015. We estimated the crude incidence rates and age- and sex-standardized incidence rates in each 12-year study period. To determine the trend, we also performed joinpoint regression analyses. We identified 240,495 incident RVO cases. The average incidence rate was 48.09 (95% confidence interval [CI], 47.92-48.27). Women showed a 1.24 times higher incidence rate (53.18 [95% CI, 52.92-53.44]) compared with men (42.78 [95% CI, 42.55-43.02]), while, among patients aged less than 50years and those aged 80years or over, men showed higher incidence rates than did women. The highest incidence of 193.56 (95% CI, 191.06-196.06) was observed in the age group of 75 to 79years. The joinpoint analysis showed an increasing trend of RVO incidence among patients at the age of 70years and older (annual percentage change, 2.1; 95% CI, 0.2-4.0; p < 0.01). RVO is a disease of the elderly that peaks in the late 70s and occurs more in women than in men. In Korea, RVO incidence increased from 2004 to 2015 among the population aged 70years or older, while among those aged less than 70years, no trend was observed in RVO incidence rates.

Population-based Incidence of Pediatric and Adult Optic Neuritis and the Risk of Multiple Sclerosis

To determine the age- and sex-specific prevalence and incidence of demyelinating optic neuritis and the risk of multiple sclerosis (MS) in pediatric and adult populations in South Korea. A nationwide, population-based, retrospective study using data from the Korean National Health Claims database from 2010 to2016. The entire South Korean population aged 65 years of age or younger (n= 44 700 564). All patients with optic neuritis from the entire Korean population were included. Patients aged 14 years of age or younger were classified as pediatric patients, and those aged 15 to 65 years were classified as adults. Each group was analyzed separately. Patients with optic neuritis had a subsequent diagnosis, including idiopathic, MS, neuromyelitis optica (NMO), and acute disseminated encephalomyelitis. Prevalence and incidence, conversion rate to MS, and treatment modalities (steroids, plasmapheresis, interferon-β, and immunosuppressants) were estimated. Prevalence and incidence of optic neuritis, and conversion rate to MS. Among 44 700 564 individuals, 531 pediatric patients (50.7% female) and 7183 adults (53.3% female) were identified as having optic neuritis. Annual incidence was 1.04 (95% confidence interval [CI], 1.01-1.07) per 100 000 pediatric individuals and 3.29 (95% CI, 3.28-3.30) per 100 000 adults. Peak incidence was observed at 10 to 14 years in the pediatric population and at 30 to 34 years and 50 to 54 years in the adult population. Conversion rate to MS was 13.8% in the pediatric population and 11.4% in the adult population. Fourteen percent of all patients were treated with chronic immunosuppressants, 38% of patients with NMO underwent plasmapheresis, and 50% of patients with MS were treated with interferon-β. This is a nationwide epidemiologic study of optic neuritis in individuals of all ages in South Korea. The incidence of optic neuritis and subsequent risk of MS in the pediatric population are comparable to those reported in western countries but are lower in the adult population than in western countries. The incidence rate in adults was 3.2-fold higher than in the pediatric population, and the overall MS conversion rate in the entire Korean population was estimated to be 10.6%.

Five-year nationwide incidence of macular hole requiring surgery in Korea

Background/aimsTo estimate the incidence and demographics of macular hole (MH) requiring surgery in Korea.MethodsPatients who underwent surgery for MH in Korea from 2011 to 2015 with the diagnostic code for...

Risk of Ischemic Kidney Injury in Patients With Nonarteritic Anterior Ischemic Optic Neuropathy: A Nationwide Population-based Study

To investigate the risk of acute tubular necrosis (ATN) in patients with nonarteritic anterior ischemic optic neuropathy (NAION). Population-based cohort study. This is a nationwide, population-based, retrospective study using data from the Korean national health claims database from 2011 through 2015. Patients with NAION and randomly selected control subjects from the entire population of South Korea were enrolled. A log-rank analysis was used to evaluate a risk of ATN in the group of patients with NAION (study group) compared to an age-, sex-, and comorbidities-matched control group. Comorbidities included diabetes, chronic lung disease, congestive heart failure, ischemic stroke, anemia, septic shock, and antibiotic use. A Cox proportional hazards regression analysis with cluster effect was performed to calculate the adjusted hazard ratio (aHR) of ATN. A total of 22 498 patients were included in the study group and 31 475 in the control group. Twenty-six cases of ATN were observed in the NAION group and 11 in the control group. The study group was more likely to have ATN (aHR= 2.55, 95% confidence interval: 1.50-5.91, P= .029) than the control group. Among the 26 newly developed cases of ATN, 13 (50%) occurred in the 0-6months before/after NAION. We demonstrated that subjects with NAION are at increased risk of ATN and suggested a possible common mechanistic link between the 2 diseases. These results provide significant evidence that proper patient education and further systemic evaluation of the possibility of ATN development are required in patients with NAION.

Prevalence and incidence of non-arteritic anterior ischaemic optic neuropathy in South Korea: a nationwide population-based study

AimsTo determine the age and sex-specific prevalence and incidence of non-arteritic anterior ischaemic optic neuropathy (NAION) in South Korea.MethodsThis is a nationwide population-based study using data from the Korean national...

Prevalence and Incidence of Exudative Age-Related Macular Degeneration in South Korea: A Nationwide Population-Based Study

To determine the prevalence and incidence of exudative age-related macular degeneration (AMD) in South Korea. Nationwide population-based retrospective study using data from the Korean national health claims database from 2008 through 2012. Entire South Korean population 40 years of age or older (n = 22,376,510). We accessed the national health claims database to identify exudative AMD patients using the registration program database for rare intractable diseases, which included ophthalmologist-confirmed exudative AMD, for copayment reduction. Prevalence and incidence rates of exudative AMD. During the 5-year study period, 81 513 patients had exudative AMD (48.2% men) and were included in the prevalence estimates. The prevalence in the general population 40 years of age or older was 36.43 (95% confidence interval [CI], 36.18-36.68) per 10,000 people, that in men was 37.01 (95% CI, 36.65-37.38) per 10,000 people, and that in women was 35.90 (95% CI, 35.56-36.24) per 10,000 people. After excluding prevalent cases during the initial 2-year washout period, 20,196 cases were identified with incident exudative AMD during the final 3-year study period (2010-2012). The incidence in the general population 40 years of age or older was 3.02 (95% CI, 2.98-3.06) per 10,000 person-years, that in men was 3.76 (95% CI, 3.69-3.83) per 10,000 person-years, and that in women was 2.34 (95% CI, 2.29-2.39) per 10,000 person-years. The prevalence and incidence increased with advancing age and peaked at approximately 80 years of age. Both the prevalence and incidence were higher in men than in women in all age groups. These detailed estimates of the nationwide, population-based prevalence and incidence of exudative AMD in an Asian population may help to understand the disease pathophysiology and to plan accordingly within the healthcare system.