New-onset atrial fibrillation in seropositive rheumatoid arthritis: association with disease-modifying anti-rheumatic drugs treatment.

OBJECTIVE: Atrial fibrillation (AF) is a potentially lethal complication that leads to increased hospitalization, disability and mortality. Furthermore, the risk of cardiovascular disease is increased in RA. We evaluated whether DMARD treatment is associated with incident AF in patients with seropositive RA (SPRA). METHODS: The South Korean Health Insurance Review and Assessment Service database was used to identify patients newly diagnosed with SPRA between 2010 and 2020. A nested case-control analysis was performed to match AF-affected patients to unaffected controls for age, sex, follow-up duration, and index year of SPRA diagnosis at a 1:4 ratio. Adjusted conditional logistic regression was used to identify the predictive factors for AF. RESULTS: Of the 108 085 patients with SPRA, 2,629 (2.4%) developed new-onset AF, and the proportion of females was ∼67%. In the matched population, pre-existing comorbidities of hypertension, chronic kidney disease, and heart failure were associated with increased risk of AF. Meanwhile, the use of methotrexate (MTX) decreased the risk of incident AF [adjusted odds ratio (aOR), 0.89], whereas the use of leflunomide (LEF) increased AF (aOR, 1.21). In a subgroup of patients aged ≥50 years, LEF and adalimumab increased the occurrence of AF, while MTX decreased AF in males and LEF increased this risk in females. CONCLUSION: Although the number of subjects developing new-onset AF was small, MTX decreased and LEF increased incident AF in patients with RA. Especially, a distinct pattern of AF risk with DMARDs usage was observed according to age and sex.

Incidence of systemic vasculitides after Mycobacterium tuberculosis infection: A population-based cohort study in Korea.

BACKGROUND: Tuberculosis (TB) is a highly prevalent disease associated with significant morbidity and mortality globally, and is reported to be associated with the onset of autoimmunity. This study investigated the association between TB and the incidence of systemic vasculitides (SV). METHODS: Data were obtained from the South Korean National Claims database to identify patients with TB and controls (who had undergone appendectomy). The overall occurrence of SV and disease subtypes during the observation period was compared between the two groups. Adjusted Cox proportional hazards regression and Kaplan-Meier analysis were performed to identify the relationship between TB and SV and to compare SV incidence. RESULTS: We identified 418 677 patients with TB and 160 289 controls. The overall SV incidence rate was 192/1,000 000 person-years during a mean follow-up of 7.5 years and was higher in patients with TB than controls. Cox regression revealed that the risk of SV was elevated in the TB group independently (adjusted hazard ratio [aHR]: 1.72, 95% confidence interval [CI]: 1.45-2.05). Furthermore, the risk of SV was significantly higher in extrapulmonary TB (aHR: 4.28, 95% CI: 3.52-5.21) when the TB group was categorized into pulmonary and extrapulmonary TB. The findings remained identical even after applying a stabilized inverse probability of treatment weighting analysis. CONCLUSIONS: Patients with TB have increased risk of SV, which is prominent in extrapulmonary TB. As well as confirming TB is associated with increased incidence of immune-related vasculitis, our findings highlight the need for clinical vigilance for early diagnosis and initiation of treatment.

Association between Mycobacterium tuberculosis infection and the risk of inflammatory arthritides.

OBJECTIVES: Tuberculosis is a highly contagious disease that has a significant impact on global health. Emerging evidence suggests that tuberculosis can lead to an altered immune response. We investigated the association between tuberculosis and the onset of inflammatory arthritides (IA). METHODS: Patients with incident tuberculosis in the South Korean National Claims database from 2010 to 2021 were included, and those who had undergone appendectomy during 2010-2011 served as controls. The onset of IA (including seropositive rheumatoid arthritis [SPRA], ankylosing spondylitis [AS], and psoriatic arthritis [PsA]) after tuberculosis was compared between patients with tuberculosis and the control group. Sensitivity analysis was performed using stabilised inverse probability of treatment weighting (sIPTW). RESULTS: A total of 408,685 patients with tuberculosis and 159,675 controls were included. During the mean follow-up of 7.5 years, a total of 1,957 (0.3%) were diagnosed with IA (SPRA, 1,397; AS, 481; and PsA, 79). Multivariable Cox hazard analysis indicated that the overall risk of IA was elevated in the tuberculosis group (hazard ratio [HR], 1.71; 95% confidence interval [CI], 1.51-1.93) compared with controls. This increased incidence in patients with tuberculosis was identical among IA subgroups even after adjustment (SPRA [HR, 1.72; 95% CI, 1.49-2.00], AS [HR, 1.64; 95% CI, 1.30-2.06], and PsA [HR, 2.59; 95% CI, 1.32-5.07]) and was replicated in the sIPTW. CONCLUSIONS: The increased overall risk of developing IA after tuberculosis corroborates the hypothesis that tuberculosis can trigger dysregulated immunity. This necessitates an increased awareness of autoimmunity in this patient group.

Effect of Corticosteroid Use on the Occurrence and Progression of Osteonecrosis of the Femoral Head: A Nationwide Nested Case-Control Study.

BACKGROUND: Although it is very well known that corticosteroids cause osteonecrosis of the femoral head (ONFH), it is unclear as to which patients develop ONFH. Additionally, there are no studies on the association between corticosteroid use and femoral head collapse in ONFH patients. We aimed to investigate the association between corticosteroid use and the risk of ONFH among the general population and what factors affect ONFH occurrence. Additionally, we aimed to demonstrate which factors affect femoral head collapse and total hip arthroplasty (THA) after ONFH occurrence. METHODS: A nationwide, nested case-control study was conducted with data from the National Health Insurance Service Physical Health Examination Cohort (2002 to 2019) in the Republic of Korea. We defined ONFH (N = 3,500) using diagnosis and treatment codes. Patients who had ONFH were matched 1:5 to form a control group based on the variables of birth year, sex, and follow-up duration. Additionally, in patients who have ONFH, we looked for risk factors for progression to THA. RESULTS: Compared with the control group, ONFH patients had a low household income and had more diabetes, hypertension, dyslipidemia, and heavy alcohol use (drinking more than 3 to 7 drinks per week). Systemic corticosteroid use (≥1,800 mg) was significantly associated with an increased risk of ONFH incidence. However, lipid profiles, corticosteroid prescription, and cumulative doses of corticosteroid did not affect the progression to THA. CONCLUSIONS: The ONFH risk increased rapidly when cumulative prednisolone use was ≥1,800 mg. However, oral or high-dose intravenous corticosteroid use and cumulative dose did not affect the prognosis of ONFH. Since the occurrence and prognosis of ONFH are complex and multifactorial processes, further study is needed.

A decrease in the incidence of encephalitis in South Korea during the COVID-19 pandemic: A nationwide study between 2010 and 2021.

Limited data are available on the impact of the coronavirus disease (COVID-19) pandemic on encephalitis. Therefore, we evaluated trends in encephalitis in South Korea between 2010 and 2021 using data from the National Health Insurance Service. During the pandemic (February 2020 to 2021), the monthly incidence of encephalitis declined by 0.027 per 100 000 population (95% confidence interval [CI]: -0.055 to 0.001, p = 0.062) compared to that before the pandemic. In subgroup analysis, the estimated coefficient for level change during the pandemic in the 0-4 and 5-9 years age groups were -2.050 (95% CI: -2.972 to -1.128, p < 0.001) and -0.813 (95% CI: -1.399 to -0.227, p = 0.008), respectively. The annual incidence of encephalitis during the pandemic period significantly decreased in the 0-4 and 5-9 years age groups (incidence rate ratio: 0.34 [p = 0.007] and 0.28 [p = 0.024], respectively). The intensive care unit admission rate (39.1% vs. 58.9%, p < 0.001) and cases of death (8.9% vs. 11.1%, p < 0.001) decreased significantly during the pandemic compared to the prepandemic. During the pandemic, the incidence of encephalitis decreased markedly in South Korea, particularly in children aged ≤9 years. In addition, there were changes in the clinical outcome of encephalitis during the COVID-19 pandemic.

Incidence of septic arthritis in patients with ankylosing spondylitis and seropositive rheumatoid arthritis following TNF inhibitor therapy.

OBJECTIVES: Septic arthritis (SA) is a serious complication occurring in the joints, and its risk increases with immunosuppressive therapy. This study investigated whether TNF inhibitors increase the risk of SA in patients with AS and seropositive RA (SPRA). METHODS: We searched the South Korean Health Insurance Review and Assessment Service database for incident cases of AS and SPRA between 2010 and 2020. SA was defined using the diagnostic code M00 and hospital admission. Cox-proportional hazards analysis was conducted to compare the incidence of SA according to TNF inhibitor (infliximab, etanercept, adalimumab/golimumab) use during follow-up. RESULTS: Of the 145 129 patients analysed, 1170 (0.8%) developed SA during the follow-up period. Older age; male sex; SPRA diagnosis; comorbidities of hypertension (HTN), diabetes mellitus (DM) and chronic pulmonary disease (CPD); and infliximab and etanercept use increased the incidence of SA in the overall population. However, in patients with AS, only age and renal disease were predictors of SA, and TNF inhibitors did not increase the incidence of SA. Meanwhile, patients with SPRA treated with TNF inhibitors were prone to SA regardless of TNF inhibitor type, and age, HTN, DM and CPD were associated with SA. The incidence of SA was prominent after the first year of commencing TNF inhibitor therapy, for both AS and SPRA. CONCLUSION: TNF inhibitors increase the incidence of SA, specifically in patients with SPRA, but not AS. Importantly, age, comorbidities and the early time period after starting TNF inhibitors were associated with SA, which should be considered simultaneously when initiating TNF inhibitor therapy.

Cancers and cardiovascular diseases in patients with seropositive rheumatoid arthritis treated with JAK inhibitors, biologics and conventional synthetic DMARDs.

OBJECTIVES: Janus kinase inhibitors and biologics (JAKi/biologics) are cornerstone treatments for rheumatoid arthritis (RA). We evaluated the risks of cancers and cardiovascular diseases (CVDs) in patients with seropositive RA (SPRA) treated with JAKi/biologics. METHODS: Patients with new-onset SPRA during 2010-2020 in the national healthcare database were identified. Events of overall and site-specific cancers, as well as CVD outcomes, including deep vein thrombosis, pulmonary embolism, and composite cardiovascular events, were investigated. The relative risk of cancers and CVDs compared to conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) users was compared by evaluating the incidence rate ratios (IRRs). Time-dependent Cox analyses were performed to evaluate the relationship between JAKi/biologics usage and patient outcomes. RESULTS: A total of 101,816 and 96,220 patients with SPRA were analysed for cancers and CVD outcomes, respectively. Compared with patients treated only with csDMARDs, the IRRs of overall cancers and CVDs in patients administered JAKi/biologics were 0.88 (95% confidence interval [CI] 0.86-0.89) and 0.91 (95% CI 0.90-0.92), respectively. Site-specific lung, liver, prostate, and skin cancers were more frequent in JAKi/biologics users; JAKi did not confer a greater risk of overall CVDs and cancers compared with other biologics and csDMARDs. JAKi/biologics usage was not accounted for overall cancers and CVDs in adjusted Cox analyses. CONCLUSIONS: The incidence of overall cancer and CVD were not increased in patients with SPRA treated with JAKi/biologics and was relatively lower than csDMARD only users, underscoring optimal disease control for risk mitigation. The higher incidence of several site-specific cancers requires further investigation.

Aortic valve surgery in patients with Takayasu's arteritis: a nationwide analysis of 1,197 patients during a 9-year period.

OBJECTIVES: Takayasu's arteritis (TAK) is associated with an elevated risk of valvular heart disease, especially in the aortic valve. This study aimed to evaluate the rate and risk factors of aortic valve surgery (AVS) in patients with TAK. METHODS: The clinical data of 1,197 patients were identified in the Korean National Health Insurance Claims database between 2010 and 2018. Case ascertainment was done by using the ICD-10 code of TAK and inclusion in the Rare Intractable Diseases registry. The incidence rate/1,000 person-years was calculated to compare the age- and sex- adjusted incidence rate ratio (IRR) of AVS according to the time period between TAK diagnosis and AVS: <1 year, 1-2 years, 2-3 years, and 3 years. Evaluation of factors associated with AVS was performed using a time-dependent Cox regression analysis. RESULTS: Forty-five patients (3.8%) underwent AVS during the follow-up. The mean follow-up duration of patients with AVS was 1.2 years, and two-thirds of the patients (66.7%) underwent AVS within 1 year. The adjusted IRR was significantly higher among patients who underwent AVS <1 year after the diagnosis of TA than among those who underwent AVS ≥3 years after diagnosis (adjusted IRR: 10.31; 95% confidence interval [CI]: 4.29-24.81). A history of hypertension before the diagnosis of TAK was an independent risk factor for AVS (adjusted hazard ratio: 2.18; 95% CI: 1.12-4.24). CONCLUSIONS: Approximately 4% of patients with TAK undergo AVS, usually within the first year of TAK diagnosis. Previous history of hypertension is a risk factor for AVS.

Impact of Dyslipidemia on the Risk of Second Cancer in Thyroid Cancer Patients: A Korean National Cohort Study.

BACKGROUND: Studies have shown that radioactive iodine therapy (RAIT) affects the development of second cancer in thyroid cancer patients. The impact of other factors, such as dyslipidemia are not clear. METHODS: A retrospective analysis of thyroid cancer patients with a 1,251,913 person-year follow-up was conducted using data from the Health Insurance Review and Assessment database in South Korea from January 2008 to December 2018. We investigated factors related to second cancer development using a nested case-control analysis to avoid length bias. RESULTS: The overall risk of developing second cancer was higher in thyroid cancer patients than in the general population [standardized incidence ratio, 3.34; 95% confidence interval (CI) 3.30-3.39]. Second cancer incidence was higher in patients who received RAIT than in those who did not [odds ratio (OR) 1.130; 95% CI 1.094-1.169]. Moreover, the risk of second cancer was higher in patients with dyslipidemia than in those without dyslipidemia (OR 1.265; 95% CI 1.223-1.309). After adjustment for RAIT, the incidence of a second cancer was higher in patients with dyslipidemia than in those without dyslipidemia (OR 1.262; 95% CI 1.221-1.306). CONCLUSIONS: The risk of second cancer development in patients with thyroid cancer appears to be high. Dyslipidemia may be associated with an increased risk of several types of second cancers.

Markedly increased risk of malignancies in women with endometriosis.

OBJECTIVE: To assess the cancer risk in a cohort of women with newly diagnosed endometriosis. METHODS: This retrospective, nationwide, population-based cohort study utilized data from the 10-year claims database of the Korean National Health Insurance from January 2008 to December 2018. Patients diagnosed with endometriosis between 2010 and 2013 were included; those who underwent appendectomy but were not diagnosed with endometriosis during the study period served as controls. No participant was diagnosed with cancer before enrollment. Cancer diagnoses according to the International Classification of Diseases, 10th revision, were compared between the two groups. Cancer occurrence in both groups was identified according to the diagnostic codes for different organ sites. RESULTS: Altogether, 179,865 patients with endometriosis and 87,408 controls were analyzed, and the incidence rates of cancer were 644.3 and 543.8 per 100,000 person-years, respectively. Patients with endometriosis had a significantly increased overall cancer risk (hazard ratio [HR], 1.34; 95% confidence interval [CI], 1.28-1.40; p < 0.001) than controls after adjusting for age, insurance type, and comorbidities. They had significantly increased uterine (HR, 4.59; 95% CI, 3.56-5.91; p < 0.001), ovarian (HR, 2.51; 95% CI, 1.99-3.16; p < 0.001), cervical (HR, 1.84; 95% CI, 1.49-2.28; p < 0.001), breast (HR, 1.44; 95% CI, 1.31-1.58; p < 0.001), and thyroid cancer (HR, 1.34; 95% CI, 1.24-1.45; p < 0.001) risk. Median age at diagnosis was <50 years for all cancer types. CONCLUSIONS: Endometriosis was associated with an increased cancer risk, specifically uterine, ovarian, cervical, breast, and thyroid cancers, suggesting that effective cancer screening for early detection of malignancies in women should be implemented in those with endometriosis.

A nationwide nested case-control study of new-onset obsessive-compulsive disorder following antipsychotics use in schizophrenia.

OBJECTIVE: A substantial proportion of patients with schizophrenia suffer from comorbid obsessive-compulsive disorder (OCD) possibly associated with antipsychotics. However, little is known about the comparative risks of the antipsychotics. The present study aimed to investigate the risk of new-onset OCD following the initiation of different antipsychotic medications for schizophrenia relative to haloperidol. METHODS: Using the Korean national claims data, patients aged 15-60 years newly diagnosed with schizophrenia between 2010 and 2018 were identified. Of the 47,808 patients with schizophrenia treated with nine commonly prescribed antipsychotics, 775 new-onset OCD patients were matched to 3,100 patients without OCD using nested case-control design with 1:4 case-control matching based on the sex, age of index date, date of schizophrenia diagnosis, observation period, locations of medical institutions, and level of medical facilities. Using multivariable conditional logistic regression analysis, odd ratios (ORs) for new-onset OCD comparing each antipsychotic agent relative to haloperidol were computed. RESULTS: The risk for new-onset OCD during treatment with clozapine was significantly higher than that with haloperidol (adjusted OR 2.86; 95% confidence interval [1.63-5.03]). The risks for new-onset OCD with other antipsychotics were not significantly different from that with haloperidol. In subgroup analysis, the early and intermediate, but not late-onset schizophrenia group showed significant risk for OCD associated with clozapine use. CONCLUSION: The present findings, based on real-world national representative data, provide reliable evidence for the risk of new-onset OCD in patients with schizophrenia receiving clozapine at a population level.

Revised Korean Antiviral Guideline Reduces the Hepatitis B-related Hepatocellular Carcinoma Risk in Cirrhotic Patients.

BACKGROUND: Since September 2015, the initiation of antiviral therapy (AVT) for patients with chronic hepatitis B (CHB)-related cirrhosis has been reimbursed according to the revised Korean Association for the Study of Liver (KASL) guideline, if the patient had hepatitis B virus DNA level ≥ 2,000 IU/L, regardless of aminotransferase or alanine aminotransferase levels. This study investigated whether the KASL guideline implementation reduced the risk of CHB-related hepatocellular carcinoma (HCC) in patients with cirrhosis in South Korea. METHODS: A total of 429 patients with CHB-related cirrhosis who initiated AVT between 2014 and 2016 were recruited. The risk of HCC development was compared between patients who initiated AVT before and after September 2015 (pre-guideline [n = 196, 45.7%] vs. post-guideline implementation [n = 233, 54.3%]). RESULTS: Univariate analysis showed that AVT initiation before guideline implementation, older age, male gender, and diabetes significantly predicted increased risk of HCC development (all P < 0.05). Subsequent multivariate analysis showed that AVT initiation before guideline implementation (HR = 1.941), older age (HR = 5.762), male gender (HR = 2.555), and diabetes (HR = 1.568) independently predicted increased risk of HCC development (all P < 0.05). Additionally, multivariate analysis showed that AVT initiation before guideline implementation (HR = 2.309), male gender (HR = 3.058), and lower platelet count (HR = 0.989) independently predicted mortality (P < 0.05). The cumulative incidences of HCC and mortality were significantly higher in patients who initiated AVT before guideline implementation than in those who initiated AVT after guideline implementation (all P < 0.05, log-rank test). CONCLUSION: The prognosis of patients with CHB-related cirrhosis who initiated AVT improved after guideline implementation according to the revised KASL guideline.

The Association of Calcium and Vitamin D Use With Implant Survival of Total Knee Arthroplasty: A Nationwide Population-Based Cohort Study.

BACKGROUND: Calcium and vitamin D have been regarded as beneficial nutrients for bone metabolism that may affect survival of arthroplasties. However, the relationship between their use and revision rate of knee arthroplasty has not been evaluated. Thus, we investigated an association between calcium and vitamin D use and the revision rate after primary total knee arthroplasty. METHODS: A nationwide population-based cohort study was conducted using the Korean National Health Insurance database. We included patients diagnosed with knee osteoarthritis and underwent primary total knee arthroplasty between 2009 and 2018. Risk for arthroplasty revision was estimated using a Cox proportional hazards model with time-dependent covariates. Log-rank test was used to assess survival of knee arthroplasty. RESULTS: Out of 142,147 subjects, 28,403 were calcium and vitamin D users and 113,744 were never users. Calcium and vitamin D significantly reduced the revision risk with a 6-month drug use lag period (adjusted hazard ratio [aHR] 0.56, 95% confidence interval [CI] 0.45-0.70). Calcium and vitamin D combination use for more than 1 year was associated with reduced revision risks in both patients with periprosthetic joint infection (aHR 0.63, 95% CI 0.42-0.95) and patients without infection (aHR 0.70, 95% CI 0.54-0.91). Implant survival was significantly improved in calcium and vitamin D combination users for more than 1 year compared with never users (log-rank P < .001). CONCLUSION: Combination use of calcium and vitamin D with a dose of 800 IU or greater for more than 1 year was associated with the greatest reduction in the risks for revision surgery after total knee arthroplasty.

Biologic Use Patterns and Predictors for Non-persistence and Switching of Biologics in Patients with Inflammatory Bowel Disease: A Nationwide Population-Based Study.

BACKGROUND: Data on real-life patterns of biologic use for inflammatory bowel disease (IBD) are scarce. AIMS: We aimed to examine the patterns of biologic use and the factors associated with non-persistence and switching of biologics in Korean IBD patients. METHODS: Using National Health Insurance claims, we collected data on patients who were diagnosed with IBD and exposed to biologics between 2010 and 2016. RESULTS: Among 1838 patients with Crohn's disease (CD), 1237 and 601 started with infliximab and adalimumab, respectively. Among 1125 patients with ulcerative colitis (UC), 774, 294, and 57 initiated infliximab, adalimumab, and golimumab, respectively. Rates of non-persistence and switching were higher in UC than in CD. One- and 3-year non-persistence rates were 14.2% and 26.5% in CD and 35.4% and 53.4% in UC, respectively. One- and 3-year switching rates were 3.7% and 10.1% in CD and 15.6% and 22.0% in UC, respectively. In both CD and UC, infliximab and adalimumab initiators showed similar persistence rates, whereas adalimumab initiators had a higher risk of switching than infliximab initiators. In UC, golimumab initiators had a higher risk of non-persistence and switching than infliximab initiators. Steroid use at biologic initiation was associated with an increased risk of non-persistence and switching in both CD and UC. UC patients who started biologic treatment at tertiary hospitals were more likely to continue treatment than those who started at general hospitals/community hospitals/clinics. CONCLUSIONS: In real-world clinical practice settings, discontinuation of biologics occurred frequently in IBD patients, and switching of biologics was common in UC patients.

Long-term Effects of Cumulative Average PM2.5 Exposure on the Risk of Hemorrhagic Stroke.

BACKGROUND: Epidemiological studies have revealed associations between the fine particle (PM2.5; aerodynamic diameter <2.5 µm) exposure and cardiovascular disease. Researchers have also recently begun investigating the association between PM2.5 exposure and hemorrhagic stroke (HS) and identifying subpopulations vulnerable to PM2.5 exposure. Long-term cumulative average PM2.5 exposure may affect the risk of HS, and these effects may be modified by risk factors. METHODS: This retrospective study evaluated the effects of PM2.5 on the time-to-first-diagnosis of HS among 62,676 Seoul metropolitan city residents with 670,431 total person-years of follow-up; this cohort is a subset from a nationally representative cohort of 1,025,340 individuals from the Korean National Health Insurance Service database (2002-2013). A time-dependent Cox proportional hazards model was used to adjust for age, sex, household income, insurance type, body mass index, smoking status, medical history, and family history. The annual mean PM2.5 concentrations for 25 districts were used as the time-dependent variable. Subgroup analyses of the traditional risk factors of HS were performed to evaluate potential effect modifications. RESULTS: Each 10-µg/m increment in cumulative average PM2.5 exposure was noticeably associated with HS (hazard ratio [HR] = 1.43; 95% confidence interval [CI]: 1.09-1.88). The adverse effects of PM2.5 exposure were modified by ≥65 years of age (HR = 2.00; 95% CI = 1.32, 3.02) and obesity (body mass index ≥25 kg/m; HR = 1.91; 95% CI = 1.28, 2.84). CONCLUSIONS: Cumulative average PM2.5 exposure might increase the risk of HS. Elderly (≥65 years) and obese individuals may be more vulnerable to the effects of PM2.5 exposure.

Regional variations in the use of biologics and immunomodulators among Korean patients with inflammatory bowel diseases.

BACKGROUND AND AIM: Variation in medical care can be an obstacle to improving quality and outcome of treatment. We conducted a nationwide, population-based study to identify regional variations in medication prescription rates in Korean patients with inflammatory bowel diseases (IBDs). METHODS: Using the National Health Insurance claims, we collected data on patients diagnosed with IBD (8974 cases of Crohn's disease [CD] and 17 167 cases of ulcerative colitis [UC]) between 2010 and 2016. RESULTS: Overall rates of biologics (infliximab or adalimumab) use in CD and UC were 19.6% and 6.1%, respectively, and those of immunomodulator (azathioprine or 6-mercaptopurine) use were 66.9% and 20.4%, respectively. The average periods from diagnosis to first biologics use for CD and UC were 1.6 and 1.8 years, respectively, and those of immunomodulators were 0.6 and 1.3 years, respectively. In Seoul, Daegu, and Busan, three major cities in Korea, biologics prescription rates for CD were 20.7%, 22.9%, and 14.6%, respectively, and those for UC were 7.3%, 6.7%, and 4.5%, respectively. In the top 7 regions with the highest number of patients in Seoul, there were 3.6-fold and 3.2-fold variations between regions with the highest and lowest frequency of biologics use in CD and UC, respectively. In addition, there were 1.6-fold and 2.8-fold variations between regions with the highest and lowest frequency of immunomodulator use for CD and UC, respectively. CONCLUSIONS: Regional variation exists in medication prescription rates within a single city as well as nationwide, suggesting that standardization of IBD treatment is necessary in Korea.

Evaluation of the directional relationship between handgrip strength and cognitive function: the Korean Longitudinal Study of Ageing.

BACKGROUND: recent studies suggest that handgrip strength is linked with cognitive impairment at older ages. However, it remains unclear as to whether muscular strength influences subsequent cognitive performance, or whether lower levels of cognitive function increase the likelihood of muscle strength decline. OBJECTIVE: to investigate the directional relationship between handgrip strength and cognitive impairment using longitudinal data among older adults. METHODS: repeated measures of handgrip strength and cognitive function were collected in a sample of 5,995 participants of the Korean Longitudinal Study of Aging (KLoSA) over a period of 8 years. Time-lagged general estimating equations, while accounting for correlation among repeated measures, was used to assess the temporal effect of handgrip strength on cognitive impairment and vice versa with adjustment for other confounding factors. RESULTS: after adjustment, greater handgrip strength was related to subsequent reduction in the risk of cognitive impairment, such that participants in the highest quartile presented approximately 50% decrease in their risk of cognitive impairment [adjusted odds ratio (OR) = 0.499 (95% CI 0.422 to 0.589] compared to the lowest quartile after controlling for potential confounding factors. Conversely, cognitive impairment was a significant predictor of reduced muscular strength [ß regression coefficient -0.804, 95% CI, -1.168 to -0.439, for participants with dementia compared with those with normal cognitive function]. CONCLUSIONS: in conclusion, a significant bi-directional relationship was found between muscular strength and cognitive function, suggesting that these may have shared common pathways that are worthy of being further elucidated in future studies.

Update on the prevalence and incidence of rheumatoid arthritis in Korea and an analysis of medical care and drug utilization.

The objectives of this study are to identify the prevalence and incidence of rheumatoid arthritis (RA) and to investigate the patterns of medical care and drug utilization by RA patients in Korea. Korean National Health Insurance claims data were used for analysis. RA patients were defined as those having an RA code from 2009 to 2012 and using disease-modifying anti-rheumatic drugs (DMARDs) within 1 year after the code. RA patients identified in 2010 with a disease-free period for 12 months before the index date, and those who received continuous treatment in 2011-2013 were defined as incident cases. Patterns of medical care and drug utilization were compared among subgroups. The prevalence of RA increased yearly from 0.28% in 2009 to 0.32% in 2012. The incidence of RA in 2010 was 28.5 per 100,000 person-years. The use of biologic DMARDs (bDMARDs) increased from 2.31% in 2009 to 4.05% in 2012. Hydroxychloroquine (57.53-62.45%) was the most commonly used the conventional DMARDs, followed by methotrexate (49.99-51.87%). The use of bDMARDs (1.39 vs. 2.43%) was less frequent in EORA patients than YORA patients. Hydroxychloroquine (74.96 vs. 72.11%) was more frequently used, but methotrexate (55.24 vs. 59.25%) and sulfasalazine (27.96 vs. 32.72%) were used less frequently in EORA patients than in YORA patients. The prevalence of RA has increased in Korea. EORA patients used fewer bDMARDs, methotrexate, and sulfasalazine but more hydroxychloroquine than YORA patients.

Incidence and Clinical Outcomes of Inflammatory Bowel Disease in South Korea, 2011-2014: A Nationwide Population-Based Study.

BACKGROUND: The incidence of inflammatory bowel disease (IBD) is increasing in East Asia; however, population-based data from this region are lacking. AIM: We conducted a nationwide, population-based study to examine the incidence and disease course of IBD in South Korea. METHODS: Using the National Health Insurance claims data, we collected data on patients diagnosed with IBD [10,049 with ulcerative colitis (UC) and 5595 with Crohn's disease (CD)] from 2011 to 2014. RESULTS: During the study period, the average annual incidence of UC was 5.0 per 105, while that of CD was 2.8 per 105. Among patients with UC, the cumulative rates of surgery 1 and 4 years after diagnosis were 1.0 and 2.0%; those among patients with CD were 9.0 and 13.9%, respectively. The 1- and 4-year cumulative rates of moderate- to high-dose corticosteroid use were, respectively, 26.6 and 45.2% among patients with UC, and 29.9 and 50.8% among those with CD. Similarly, the 1- and 4-year cumulative rates of immunomodulator use were 14.1 and 26.4% among patients with UC, and 58.3 and 76.1% among those with CD, respectively. With regard to biologic use, the 1- and 4-year cumulative rates were 3.0 and 9.0% among patients with UC, and 11.1 and 31.7% among those with CD, respectively. CONCLUSIONS: The recent incidence of IBD in South Korea has been the highest in East Asia. Patients who had been diagnosed recently with IBD showed lower rates of surgery and higher rates of immunomodulator and biologic use compared to those reported ever in South Korea.