Korean Classification Research Articles

Development of a Korean version of simple, intuitive descriptions for clinical use of the generic functioning domains in the ICD-11 Chapter V

Purpose To develop a Korean version of simple, intuitive descriptions (SIDs) for clinical use of the generic functioning domains in the International Classification of Disease 11th revision (ICD-11) Chapter V. Methods The initial Korean SID version proposal for the International Classification of Functioning, Disability, and Health (ICF) Rehabilitation set was translated following the Italian version. The remaining 17 codes were developed using original ICF descriptions; WHO Disability Assessment Schedule, Model Disability Survey, Korean Classification of Functioning, Disability, and Health; and previous studies. The final proposal for the Korean version of SIDs was selected through virtual conferences and three rounds of voting. Results This study developed SIDs for the 47 generic functioning domains in the Chapter V of ICD-11. However, the SID for 20 of the 47 codes was confirmed in vote A, for 23 codes in vote B and for the remaining 4 in the final vote. All experts agreed with the final SID proposal. Conclusions This is the first study in South Korea to attempt the development of SIDs for ICD-11 Chapter V. Therefore, the findings of this study could be used to evaluating of disability, functioning when ICD-11 is adopted for use in Korean clinical settings.

Incidence of Postoperative Rerupture of Achilles Tendon and Associated Risk Factors in South Korea: A National Population-Based Study

Category: Sports; Ankle Introduction/Purpose: Achilles tendon rerupture (ATRR) is a frequently occurring complication following the treatment of an Achilles tendon rupture (ATR) that can lead to disability; however, comprehensive risk factors for the development of postoperative ATRR remain unclear. We aimed to determine the incidence rate of postoperative ATRR and its associated risk factors, including comorbidities and medication, among the South Korean population. Methods: This study was performed based on Health Insurance Review and Assessment claims data, which covers 98% of the overall Korean population. Patients with ATR were identified according to the disease code S86.0 (Achilles tendon injury) of the Korean classification of disease between 2007 and 2020, and a washout period of 1 year was set. Instances of reoperation on the Achilles tendon between 42 and 365 days after the initial surgery, in the absence of infection or skin necrosis, were classified as cases of Achilles tendon rerupture (ATRR). Data on age, sex, comorbidities, and medications were collected and statistically analyzed. Results: Between 2009 and 2018, the incidence of surgical treatment for primary ATR was 9.91 per 100,000 person-years, showing a significant annual increase. The postoperative rerupture rate was 2.14% and did not show a significant increase. Male sex, young age, preexisting Achilles tendinopathy, osteoarthritis, and preoperative exposure to non-steroidal anti-inflammatory drugs and opioids were risk factors for postoperative ATRR. Conclusion: This information needs to be considered when determining the surgical treatment for patients with Achilles tendon rupture. The study results provoke further biological and clinical research on the risk factors for postoperative ATRR.

Incidence and prevalence of Spinal and bulbar muscular atrophy in South Korea: a nationwide population-based study.

Spinal and bulbar muscular atrophy (SBMA), or Kennedy's disease, is a rare X-linked neuromuscular disorder predominantly affecting males and caused by a mutation in the androgen receptor gene. The epidemiology and comorbidities associated with SBMA in different ethnicities remain poorly understood. This study investigated the prevalence, incidence, and comorbidities associated with SBMA in the South Korean population using the Health Insurance Review and Assessment Service (HIRA) database. We retrospectively reviewed diagnosed cases of SBMA (G12.25 code of the Korean Classification of Diseases-7th edition) registered from January 1, 2016, to December 31, 2019, to calculate incidence and prevalence rates and concomitant comorbidities. Additionally, we surveyed SBMA patients (questionnaire group) visiting our clinic in 2022 to compare comorbidities with the HIRA data. The mean incidence rate of SBMA in the Korean population was 0.36/100,000 males from 2018 to 2019, while the prevalence rate was approximately 0.46/100,000 males from 2016 to 2019. The most common comorbidities identified in HIRA were gastritis and duodenitis (99.7%), gastroesophageal reflux (90.5%), hyperlipidemia (88.4%), and liver disorders (75.2%), which showed similar results in the questionnaire group. Additionally, gastric cancer was the most common type of cancer reported in SBMA in South Korea; although indeterminate, age-related factors may contribute to the development of cancer in these patients. Our findings provide valuable insights into the epidemiology and associated comorbidities of SBMA within the Korean population, which could inform clinical practice and future clinical research.

Domain Word Extension Using Curriculum Learning.

Self-supervised learning models, such as BERT, have improved the performance of various tasks in natural language processing. Although the effect is reduced in the out-of-domain field and not the the trained domain thus representing a limitation, it is difficult to train a new language model for a specific domain since it is both time-consuming and requires large amounts of data. We propose a method to quickly and effectively apply the pre-trained language models trained in the general domain to a specific domain's vocabulary without re-training. An extended vocabulary list is obtained by extracting a meaningful wordpiece from the training data of the downstream task. We introduce curriculum learning, training the models with two successive updates, to adapt the embedding value of the new vocabulary. It is convenient to apply because all training of the models for downstream tasks are performed in one run. To confirm the effectiveness of the proposed method, we conducted experiments on AIDA-SC, AIDA-FC, and KLUE-TC, which are Korean classification tasks, and subsequently achieved stable performance improvement.

Development of the Korean Patient Safety Incidents Code Classification System.

Attempts to understand patient safety using administrative data in Korea have been rare. This study develops a Korean patient safety incident code classification system and identifies its characteristics to boost diagnosis code usage for assessing patient safety. Based on existing literature, we selected Korean Standard Classification of Diseases 7 codes for characterizing patient safety incidents using diagnosis codes. We conducted 2 rounds of review to evaluate the codes applicability to different patient safety incidents using the Delphi method. The verified diagnosis codes were then classified by incident type. Of the 54,259 Korean Standard Classification of Diseases 7 codes, 4509 were applicable for Korean patients, which were divided into 2435 code groups and 2074 candidate groups. The codes were classified into 6 categories (diagnosis, medication, patient care, operation or procedure, infection related, and other) and then further classified into 35 subcategories. The major categories of patient safety incidents, in the order of frequency, involved medication, fluid and blood related (1719, 38.1%), operation and procedure related (1339, 29.7%), and patient care related (991, 22.0%). Meanwhile, there were only 2 codes related to diagnosis. Our study provides a basis for estimating patient safety incidents using diagnosis codes. We suggest that gradually increasing the utilization and accuracy of the patient safety incident codes will help develop effective patient safety indicators in Korea similar to other countries. Moreover, clinicians are also needed to be aware of using the developed code classification system.

안경광학과 학과계열 분류의 타당성 분석

안경광학과 학과계열 분류의 타당성 분석

Individual Differences in the Association of Lifestyle with Cardiometabolic Risk in Middle-Aged Koreans Based on Traditional Korean Medicine.

Cardiometabolic (CM) risk differs in morbidity and disease progression depending on lifestyle and individual characteristics. This cross-sectional study aimed to analyze the association between CM risk and lifestyle and examine whether this association varies based on Sasang constitution (SC), a Korean medicine classification. Data were analyzed from 1996 individuals participating in the Korean Medicine Daejeon Citizen Cohort study. Individuals with CM risk had two to five CM risk factors. Lifestyle factors included physical activity, sleep duration, and eating index. SC types were Taeeum-in (TE) and non-TE. We estimated the odds ratio (OR) and 95% confidence interval for CM risk based on SC and lifestyle factors. Among the participants, 33.9% had a CM risk, and the TE and non-TE groups were 26.2% and 7.7%, respectively. In the TE group, CM risk was associated with low physical activity (OR, 1.63) and moderate eating index (OR, 1.41). In the non-TE group, CM risk was associated with ≥8 h of sleep (OR, 1.87) and marginally associated with ≤6 h of sleep. In the TE group alone, CM risk was significantly associated with lifestyle patterns that combined the three lifestyle factors and was approximately two-fold higher in patterns involving less physical activity. The effects of lifestyle on CM risk differed across SC types. To decrease the burden of cardiovascular diseases in middle-aged adults, we recommend an individualized management strategy of healthy lifestyle interventions for cardiovascular risks.

Association between atrial fibrillation and the risk of glaucoma development: a 12-year Nationwide cohort study.

To investigate the risk of glaucoma development in patients with atrial fibrillation (A-fib) using Korean National Health Insurance Service data. The present study used a National Sample Cohort consisting of approximately one million random subjects who were tracked from 2002 to 2013 (12 years). Newly diagnosed glaucoma and A-fib were included based on the Korean Classification of Disease codes. The A-fib group consisted of patients who received an initial A-fib diagnosis between January 2003 and December 2007 as an index period (n = 8765). The control group (n = 43,352) was selected using a 1:5 propensity-score matching for social and demographic factors. Each subject was followed up until 2013. Multivariate Cox proportional hazard regression analysis was performed to compare the risk of glaucoma development between the A-fib group and the control group. The rate of glaucoma development was 3.54% in the A-fib group and 2.96% in the control group (P < 0.0001). A-fib increased the risk of glaucoma development [hazard ratio = 1.31; 95% confidence interval (CI): 1.15 to 1.48] after adjusting for age, sex, comorbidities, residence, household income, and year of enrollment. In multivariable Cox regression analysis, patients with comorbidity of diabetes mellitus and chronic renal failure and those aged ≥50 years showed significantly higher risk of glaucoma development (all P < 0.001). A-fib was significantly associated with the development of glaucoma after adjusting for potential confounding factors. Physicians may need to monitor patients with A-fib carefully for possible glaucoma development.

Effectiveness of the Use of Standardized Vocabularies on Epilepsy Patient Cohort Generation.

ObjectivesThis study investigated the effectiveness of using standardized vocabularies to generate epilepsy patient cohorts with local medical codes, SNOMED Clinical Terms (SNOMED CT), and International Classification of Diseases tenth revision (ICD-10)/Korean Classification of Diseases-7 (KCD-7).MethodsWe compared the granularity between SNOMED CT and ICD-10 for epilepsy by counting the number of SNOMED CT concepts mapped to one ICD-10 code. Next, we created epilepsy patient cohorts by selecting all patients who had at least one code included in the concept sets defined using each vocabulary. We set patient cohorts generated by local codes as the reference to evaluate the patient cohorts generated using SNOMED CT and ICD-10/KCD-7. We compared the number of patients, the prevalence of epilepsy, and the age distribution between patient cohorts by year.ResultsIn terms of the cohort size, the match rate with the reference cohort was approximately 99.2% for SNOMED CT and 94.0% for ICD-10/KDC7. From 2010 to 2019, the mean prevalence of epilepsy defined using the local codes, SNOMED CT, and ICD-10/KCD-7 was 0.889%, 0.891% and 0.923%, respectively. The age distribution of epilepsy patients showed no significant difference between the cohorts defined using local codes or SNOMED CT, but the ICD-9/KCD-7-generated cohort showed a substantial gap in the age distribution of patients with epilepsy compared to the cohort generated using the local codes.ConclusionsThe number and age distribution of patients were substantially different from the reference when we used ICD-10/KCD-7 codes, but not when we used SNOMED CT concepts. Therefore, SNOMED CT is more suitable for representing clinical ideas and conducting clinical studies than ICD-10/KCD-7.

Impact of the ICD-11 on the accuracy of clinical coding in Korea.

Background: ICD-11 was officially released at the World Health Assembly on 25 May 2019. Objective: To find effective ways to increase the accuracy of coding for diagnostic terms in Korea for a stable transition from Korean modification of ICD-10 (7th Revision of Korean Classification of Disease, KCD-7) to ICD-11. Method: A total of 27 skilled Korean health information managers performed KCD-7 and ICD-11 coding simultaneously (line coding [56]; case coding [17]). Accuracy rates and percentage agreements were calculated, and granularity and difficulty of the ICD-11 were rated by participants. Results: The average accuracy rate of line coding was 71.6 % in ICD-11 and 80.2% in KCD-7, which was similar to results in other studies. The mean percentage agreements for ICD-11 and KCD-7 for line coding were 64.2% and 72.1%, respectively; while for case coding it was 15.3% and 26.6%. Selection criteria for the case scenarios may have influenced the low agreements in case coding. Cluster coding, changes of terms in ICD-11 and removal of codes used in ICD-10 contributed to low agreement in ICD-11 (46.6% of participants reported that granularity of ICD-11 was similar to ICD-10, while 36.9% reported that ICD-11 had finer granularity). In terms of difficulty, 15.3% of participants found line coding difficult and 10.9% found case coding difficult. Conclusion: Provision of more detailed reference guidelines and efficient training for coding professionals by the World Health Organization would enable ICD-11 to be an excellent tool for gathering relevant information about diseases in Korea.

Incidence, Disability, and Mortality in Patients With Guillain-Barré Syndrome in Korea: A Nationwide Population-Based Study.

Background and PurposeThis study aimed to identify the epidemiological features of Guillain-Barré syndrome (GBS) in the Korean population.MethodsPatients with GBS were defined as those who were hospitalized with a primary diagnostic code of G61.0 on the Korean Classification of Disease in a department of neurology, rehabilitation medicine, or pediatrics. We evaluated the incidence and prevalence of GBS as well as physical disability, mortality, and cause of death in patients with GBS from 2002 to 2018 in the Korean population using the Korean National Health Insurance Service database.ResultsWe identified 11,146 patients with GBS. The ratio of males to females was 1.48. The age-adjusted incidence rate per 100,000 persons increased steadily from 0.84 in 2002 to 1.68 in 2018, as did the age-adjusted prevalence rate per 100,000 persons, from 0.77 to 15.62. The incidence and prevalence of GBS increased with age, peaking at 70–79 years. Among 10,114 patients without physical disability at the time of GBS being diagnosed, 502 (5.0%) patients had moderate disability and 526 (5.2%) had severe disability by the end of the study period. A total of 1,221 (11.0%) patients with GBS died during the mean follow-up period of 17 years (2002–2019). There were 144 (1.3%) in-hospital deaths.ConclusionsThis was the first nationwide epidemiological study of patients with GBS covering the entire population including patients of all ages in the Republic of Korea. We have revealed the seasonality of admissions, disability, and long-term mortality rates in patients with GBS.

Association Between Chronic Renal Disease and the Risk of Glaucoma Development: A 12-year Nationwide Cohort Study

PurposeThe purpose of this study was to present the results of our investigation into the risk of glaucoma development in patients with chronic renal disease (CRD).MethodsThe present retrospective cohort study used the Korean National Health Insurance Service data, which consisted of 1,025,340 random subjects who were tracked from 2002 to 2013. Newly diagnosed glaucoma and CRD were included on the basis of the Korean Classification of Disease codes. The CRD group consisted of patients who received an initial CRD diagnosis between January 2003 and December 2007 as an index period (n = 3640). The control group (n = 17,971) was selected using 1:5 propensity-score matching using social and demographic factors, along with the year of enrollment. Each group subject was followed until 2013. We used multivariate Cox proportional hazard regression analysis to compare the risk of glaucoma development between the two groups.ResultsGlaucoma consecutively developed in 4.3% in the CRD group and 2.8% in the control group (P < 0.0001). CRD increased the risk of glaucoma development (hazard ratio [HR] = 1.63, 95% confidence interval [CI] = 1.34–1.98] after adjusting for age, sex, comorbidities, residence, household income, and the year of enrollment. In multivariate Cox regression analysis, patients with comorbidity of hypertension, diabetes mellitus, or aged ≥ 50 years showed a significantly higher risk of glaucoma development (all P < 0.008).ConclusionsA significant association between CRD and following development of glaucoma was revealed after adjusting the potential confounding factors.

Korean Erroneous Sentence Classification With Integrated Eojeol Embedding

This paper attempts to analyze the Korean sentence classification system. Sentence classification is the task of classifying an input sentence based on predefined categories. However, spelling or space error contained in the input sentence causes problems in morphological analysis and tokenization. This paper proposes a novel approach of Integrated Eojeol (Korean syntactic word separated by space) Embedding to reduce the effect of poorly analyzed morphemes on sentence classification. The paper also proposes two noise insertion methods that further improve classification performance. Our evaluation results indicate that by applying the proposed methods on the existing sentence classifiers, the sentence classification accuracy on erroneous sentences is increased by 8% to 15%.

Quantification of Drainage Classes of Korean Soils as Morphological Characteristics

Morphological characteristics provide a variety of important information for soils. Drainage class is also deternmined by the morphological characteristics such as soil color, which indicates the redox state of the soil. Soil color is usually measured with the Munsell color chart, which may not allow perfect conformity of results between surveyers. Quantitative approach, therefore, became more important to determine drainage class. In the quantification of the drainage class, we suggetsted following three factors as key points:ⅰ) earth color (hue, value, chroma), color due to rocks, and color due to redox are important factors, ⅱ) If there is a main color and mottles (color by reduction), the amount and degree of color by redox are important, ⅲ) When there is a groundwater level, the depth and the amount of the mottles (color by oxidation) are important determinants. Furthermore, not only the drainage class but also other characteristics should be quantified to create an Korean own classification system suitable for the characteristics of Korea. Criteria for determining the drainage class.

Cancer frequency among the patients with myotonic dystrophy in the South Korean population using the national health insurance database

Cancer frequency among the patients with myotonic dystrophy in the South Korean population using the national health insurance database

Epidemiological Characterization of a Directed and Weighted Disease Network Using Data From a Cohort of One Million Patients: Network Analysis.

BackgroundIn the past 20 years, various methods have been introduced to construct disease networks. However, established disease networks have not been clinically useful to date because of differences among demographic factors, as well as the temporal order and intensity among disease-disease associations.ObjectiveThis study sought to investigate the overall patterns of the associations among diseases; network properties, such as clustering, degree, and strength; and the relationship between the structure of disease networks and demographic factors.MethodsWe used National Health Insurance Service-National Sample Cohort (NHIS-NSC) data from the Republic of Korea, which included the time series insurance information of 1 million out of 50 million Korean (approximately 2%) patients obtained between 2002 and 2013. After setting the observation and outcome periods, we selected only 520 common Korean Classification of Disease, sixth revision codes that were the most prevalent diagnoses, making up approximately 80% of the cases, for statistical validity. Using these data, we constructed a directional and weighted temporal network that considered both demographic factors and network properties.ResultsOur disease network contained 294 nodes and 3085 edges, a relative risk value of more than 4, and a false discovery rate-adjusted P value of <.001. Interestingly, our network presented four large clusters. Analysis of the network topology revealed a stronger correlation between in-strength and out-strength than between in-degree and out-degree. Further, the mean age of each disease population was related to the position along the regression line of the out/in-strength plot. Conversely, clustering analysis suggested that our network boasted four large clusters with different sex, age, and disease categories.ConclusionsWe constructed a directional and weighted disease network visualizing demographic factors. Our proposed disease network model is expected to be a valuable tool for use by early clinical researchers seeking to explore the relationships among diseases in the future.

Improved oral hygiene is associated with decreased risk of new-onset diabetes: a nationwide population-based cohort study.

Inflammation plays an important role in the development of diabetes, a major global health problem. Periodontal disease is also common in the general population. Because periodontal disease and poor oral hygiene can provoke transient bacteraemia and systemic inflammation, we hypothesised that periodontal disease and oral hygiene indicators would be associated with the occurrence of new-onset diabetes. In this study we analysed data collected between 2003 and 2006 on 188,013 subjects from the National Health Insurance System-Health Screening Cohort (NHIS-HEALS) in Korea who had no missing data for demographics, past medical history, oral hygiene indicators or laboratory findings. The presence of periodontal disease was defined on the basis of a modified version of ICD-10 codes (Korean Classification of Disease, sixth edition), if claims for treatment for acute periodontitis (K052), chronic periodontitis (K053) and periodontosis (K054) were made more than two times by a dentist, or if, according to medical records, subjects received treatment by a dentist for periodontal disease with ICD-10 codes K052, K053 or K054. Oral hygiene behaviours (number of tooth brushings, a dental visit for any reason and professional dental cleaning) were collected as self-reported data of dental health check-ups. Number of missing teeth was ascertained by dentists during oral health examination. The incidence of new-onset diabetes was defined according to ICD-10 codes E10-E14. The criterial included at least one claim per year for both visiting an outpatient clinic and admission accompanying prescription records for any glucose-lowering agent, or was based on a fasting plasma glucose ≥7mmol/l from NHIS-HEALS. Of the included subjects, 17.5% had periodontal disease. After a median follow-up of 10.0years, diabetes developed in 31,545 (event rate: 16.1%, 95% CI 15.9%, 16.3%) subjects. In multivariable models, after adjusting for demographics, regular exercise, alcohol consumption, smoking status, vascular risk factors, history of malignancy and laboratory findings, the presence of periodontal disease (HR 1.09, 95% CI 1.07, 1.12, p < 0.001) and number of missing teeth (≥15 teeth) remained positively associated with occurrence of new-onset diabetes (HR 1.21, 95% CI 1.09, 1.33, p < 0.001, p for trend <0.001). Frequent tooth brushing (≥3 times/day) was negatively associated with occurrence of new-onset diabetes (HR 0.92, 95% CI 0.89, 0.95, p < 0.001, p for trend <0.001). Frequent tooth brushing may be an attenuating factor and the presence of periodontal disease and an increased number of missing teeth may be augmenting factors for the occurrence of new-onset diabetes. Improving oral hygiene may be associated with a decreased risk of occurrence of new-onset diabetes.

Pulmonary alveolar proteinosis in Korea: analysis of prevalence and incidence via a nationwide population-based study

BackgroundPulmonary alveolar proteinosis (PAP) is a very rare lung disease and its prevalence and incidence remain unclear. The prevalence and incidence of PAP were investigated by using nationwide claims data from the Korean Health Insurance Review and Assessment service.MethodsData were extracted for adults who visited any secondary or tertiary medical institute between 2010 and 2016 with the PAP-related Korean Classification of Disease, 7th edition code J84.0 and the Rare Intractable Disease exempted calculation code V222. To robust case definition, a narrow case definition was made when all following factors were met: 1) more than two PAP-coded visits within 1 year of the first claim, and 2) more than one claim for both chest computed tomography and diagnostic procedures (bronchoscopy or surgical lung biopsy) within 90 days before or after the first claim.ResultsA total of 182 patients (narrow, n = 82) with PAP-related codes were identified from 2010 to 2016 and 89 new patients (narrow, n = 66) visited medical institutes between 2012 and 2015. The prevalence of PAP was 4.44 (narrow: 2.27) per 106 population, with a peak age of 60–69 years. The incidence of PAP was 0.56 (narrow: 0.41) per 106 population at risk, with a peak age of 50–59 years. Among incident cases, the male-to-female ratio was 1.52 and about two-thirds had comorbidities, dyslipidaemia being the most common.ConclusionsThe prevalence and incidence of PAP in Korea are low, similar to those in other countries; however, Korean patients with PAP are characterized by older diagnostic age and a lower male-to-female ratio.

Mass balance of mercury in a pilot scale mercury recovery plant using thermal roasting technology

A pilot scale mercury recovery plant was developed to treat Hg waste by thermal treatment. The capacity of the system was 60 kg/batch and consisted of four units carrying out thermal treatment, dust separation, condensation, and flue gas treatment. The mass balances of Hg from five different wastes in three categories were calculated from Hg recovery data. From the following selected five wastes, Hg-added product, Hg-contaminated soil, byproduct of fluorescent lamp treatment process, and waste sludge from non-ferrous metal industrial process, we recovered 97.5%, 83.61%, 93.07%, 70.25%, and 29.36% of elemental mercury, respectively. Dust interfered during the condensation process, as volatilized Hg vapor was condensed with dust. Hg concentrations in leaching extract of treatment residues from the Hg-added product, Hg-contaminated soil, and the byproduct of fluorescent lamp treatment process were 0.003 mg-Hg/L, 0.0045 mg-Hg/L, and 0.002 mg-Hg/L, respectively, which are below the Korean classification standard of hazardous waste for mercury (0.005 mg-Hg/L). Hg concentration in flue gas was lower than 15 μg-Hg/m3 after passing through the activated carbon trap. Byproducts of the pilot scale system, such as activated carbon and dust can be further treated and converted to Hg free waste.

Epidemiology of Antiphospholipid Syndrome in Korea: a Nationwide Population-based Study.

BackgroundAntiphospholipid syndrome (APS) is a systemic autoimmune disorder characterized by arterial and venous thrombosis or pregnancy morbidity in patients with persistent antiphospholipid antibodies. However, nationwide population-based epidemiology studies regarding APS are still unavailable.MethodsWe analyzed claims data extracted from the Korean Health Insurance and Review Agency (HIRA) covering more than 52 million Koreans, between January 1, 2008, and December 31, 2017. Patients diagnosed with APS, as determined by the Korean Classification of Disease, 7th edition (D68.6), and a rare intractable disease program (V253), were identified in HIRA.ResultsA total of 3,088 newly diagnosed incident cases of 1,215 men and 1,873 women were identified during 2009–2016. The mean age was 44.6 ± 16.6 (men, 47.4 ± 16.3; women, 42.8 ± 16.6) years. The incidence was 0.75 per 105 person-year (95% confidence interval, 0.73–0.78). The prevalence in 2016 was 6.19 per 105 people. For incident cases, women showed incidence peak at ages of 30–39 years and 70–79 years, whereas for men, it was highest at ages of 70–79 years only. Of all patients, 1,766 (57%, 810 men and 956 women) had primary APS, 1,322 (43%, 405 men and 917 women) had secondary APS, and 845 (27%, 216 men and 629 women) were associated with systemic lupus erythematosus (SLE).ConclusionThe incidence of APS differs according to age groups and gender. The incidence of primary APS was higher than that of secondary APS in both gender. Furthermore, as already reported, secondary APS is highly associated with SLE; however, we observed that rheumatoid arthritis is also highly related.