Background: Ensuring reference material (RM) commutability is crucial for evaluating measurement traceability in order to standardize laboratory tests. However, commutability assessment is not routinely performed. We assessed whether RMs prepared following CLSI C37-A guidelines could be used without assessing commutability by evaluating their commutability for four lipid measurements using the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) and CLSI EP14 protocols. Methods: We analyzed total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) in frozen sera from 20 individuals and 11 RMs, prepared by the Korea Disease Control and Prevention AgencyLaboratory Standardization Project (per CLSI C37-A), using six routine measurement procedures (MPs). Regression equations and 95% prediction intervals derived from single-donor sera were analyzed following CLSI EP14. The IFCC protocol was used to assess differences in inter-MP biases between RM and clinical samples. The effect of the TG concentration on commutability was evaluated by analyzing biases between MP results and reference procedure-assigned values. Results: RMs were commutable for most MP pairs for TC and TG. Commutability for HDL-C and LDL-C varied across RMs, with RM10 and RM11 showing higher TG levels (2.38 and 2.95 mmol/L, respectively) and lower commutability. Increased bias percentages from assigned values were observed for RMs with higher TG levels. Conclusions RMs prepared per CLSI C37-A were commutable with most MP pairs for TC and TG. Elevated TG levels affected HDL-C and LDL-C commutability, highlighting the need to consider TG concentrations during RM preparation and assess commutability to standardize laboratory tests.

Background: and Purpose In young patients (aged 18–60 years) with patent foramen ovale (PFO)- associated stroke, percutaneous closure has been found to be useful for preventing recurrent ischemic stroke or transient ischemic attack (TIA). However, it remains unknown whether PFO closure is also beneficial in older patients. Methods: Patients aged ≥60 years who had a cryptogenic stroke and PFO from ten hospitals in South Korea were included. The effect of PFO closure plus medical therapy over medical therapy alone was assessed by a propensity-score matching method in the overall cohort and in those with a high-risk PFO, characterized by the presence of an atrial septal aneurysm or a large shunt. Results: Out of the 437 patients (mean age, 68.1), 303 (69%) had a high-risk PFO and 161 (37%) patients underwent PFO closure. Over a median follow-up of 3.9 years, recurrent ischemic stroke or TIA developed in 64 (14.6%) patients. In the propensity score-matched cohort of the overall patients (130 pairs), PFO closure was associated with a significantly lower risk of a composite of ischemic stroke or TIA (hazard ratio [HR]: 0.45; 95% confidence interval [CI]: 0.24–0.84; P=0.012), but not for ischemic stroke. In a subgroup analysis of confined to the high-risk PFO patients (116 pairs), PFO closure was associated with significantly lower risks of both the composite of ischemic stroke or TIA (HR: 0.40; 95% CI: 0.21–0.77; P=0.006) and ischemic stroke (HR: 0.47; 95% CI: 0.23–0.95; P=0.035). Conclusion Elderly patients with cryptogenic stroke and PFO have a high recurrence rate of ischemic stroke or TIA, which may be significantly reduced by device closure.

Background: and Purpose Patients with cluster headache (CH) exhibit impaired health-related quality of life (HRQoL). However, there have been few studies related to the HRQoL of patients with CH from Asian backgrounds. This study aimed to determine the impact of CH on HRQoL and to identify the factors affecting HRQoL in patients with CH during cluster periods. Methods: This prospective study enrolled patients with CH from 17 headache clinics in South Korea between September 2016 and February 2021. The study aimed to determine HRQoL in patients with CH using the EuroQol 5 Dimensions (EQ-5D) index and the time trade-off (TTO) method. Age- and sex-matched headache-free participants were recruited as a control group. Results: The study included 423 patients with CH who experienced a cluster period at the time. EQ-5D scores were lower in patients with CH (0.88±0.43, mean±standard deviation) than in the controls (0.99±0.33, p<0.001). The TTO method indicated that 58 (13.6%) patients with CH exhibited moderate-to-severe HRQoL deterioration. The HRQoL states in patients with CH were associated with current smoking patterns, headache severity, frequency, and duration, and scores on the Generalized Anxiety Disorder 7-item scale (GAD-7), Patient Health Questionnaire 9-item scale (PHQ-9), 6-item Headache Impact Test, and 12-item Allodynia Symptom Checklist. Multivariable logistic regression analyses demonstrated that the HRQoL states in patients with CH were negatively correlated with the daily frequency of headaches, cluster period duration, and GAD-7 and PHQ-9 scores. Conclusions Patients with CH experienced a worse quality of life during cluster periods compared with the headache-free controls, but the degree of HRQoL deterioration varied among them. The daily frequency of headaches, cluster period duration, anxiety, and depression were factors associated with HRQoL deterioration severity in patients with CH.

Background and Objectives: Concerns remain that early aspirin cessation may be associated with potential harm in subsets at high risk of ischemic events. This study aimed to assess the effects of P2Y12 inhibitor monotherapy after 3-month dual antiplatelet therapy (DAPT) vs.prolonged DAPT (12-month or longer) based on the ischemic risk stratification, the CHADSP2A2RC, after percutaneous coronary intervention (PCI). Methods: This was a sub-study of the SMART-CHOICE trial. The effect of the randomized antiplatelet strategies was assessed across 3 CHADS-P2A2RC risk score categories. The primary outcome was a major adverse cardiac and cerebral event (MACCE), a composite of all-cause death, myocardial infarction, or stroke. Results: Up to 3 years, the high CHADS-P2A2RC risk score group had the highest incidence of MACCE (105 [12.1%], adjusted hazard ratio [HR], 2.927; 95% confidence interval [CI], 1.358–6.309; p=0.006) followed by moderate-risk (40 [1.4%], adjusted HR, 1.786; 95% CI, 0.868–3.674; p=0.115) and low-risk (9 [0.5%], reference). In secondary analyses, P2Y12 inhibitor monotherapy reduced the Bleeding Academic Research Consortium (BARC) types 2, 3, or 5 bleeding without increasing the risk of MACCE as compared with prolonged DAPT across the 3 CHADS-P2A2RC risk strata without significant interaction term (interaction p for MACCE=0.705 and interaction p for BARC types 2, 3, or 5 bleeding=0.055). Conclusions The CHADS-P2A2RC risk score is valuable in discriminating high-ischemicrisk patients. Even in such patients with a high risk of ischemic events, P2Y12 inhibitor monotherapy was associated with a lower incidence of bleeding without increased risk of ischemic events compared with prolonged DAPT.

Background: Although rhythm control could be the best for symptomatic atrial fibrillation (AF), some patients fail to achieve sinus rhythm (SR). This study aimed to identify clinical risk factors of failed electrical cardioversion (ECV). Methods: A total of 248 patients who received ECV for persistent AF or atrial flutter (AFL) were retrospectivelyreviewed. Patients were divided into three groups: Group 1 maintained SR for > 1 year, group 2 maintained SR ≤ 1 yearafter ECV, and group 3 failed ECV. SR maintenance was assessed using regular electrocardiography or Holter monitoring. Results: Patients were divided into group 1 (73, 29%), group 2 (146, 59%), and group 3 (29, 12%). The mean ageof patients was 60 ± 10 years, and 197 (79%) were male. Age, sex, and baseline characteristics were similar amonggroups. However, increased cardiac size, digoxin use, heart failure (HF), and decreased left ventricular ejection frac‑ tion (LVEF) were more common in group 3. Univariate analysis of clinical risk factors for failed ECV was increasedcardiac size [hazard ratio (HR) 2.14 (95% confidence interval [CI], 1.06–4.34, p = 0.030)], digoxin use [HR 2.66 (95% CI, 1.15–6.14), p = 0.027], HF [HR 2.60 (95% CI, 1.32–5.09), p = 0.005], LVEF < 40% [HR 3.45 (95% CI, 1.00–11.85), p = 0.038], and decreased LVEF [HR 2.49 (95% CI, 1.18–5.25), p = 0.012]. Among them, HF showed clinical significance only by multivariate analysis [HR 3.01 (95% CI, 1.13–7.99), p = 0.027]. Conclusions Increased cardiac size, digoxin use, HF, LVEF < 40%, and decreased LVEF were related to failed ECV for persistent AF or AFL. Among these, HF was the most important risk factor. Further multi-center studies including greater number of participants are planned.

Background/Aims: Our study aimed to evaluate the long-term outcomes and risk factors forrelapse after anti-tumor necrosis factor (TNF)-α cessation in inflammatory bowel disease (IBD) patients because they are not well established. Methods: A retrospective multicenter cohort study was conducted involving patients with Crohn’s disease (CD) or ulcerative colitis (UC) from 10 referral hospitals in Korea who discontinued firstline anti-TNF therapy after achieving clinical remission. Results: A total of 109 IBD patients (71 CD and 38 UC) with a median follow-up duration of 56months were analyzed. The cumulative relapse rates at 1, 3, and 5 years were 11.3%, 46.7%, and 62.5% for CD patients and 28.9%, 45.3%, and 60.9% for UC patients. Multivariable Coxanalysis revealed that discontinuation owing to the clinician’s decision was associated with lower risk of relapse (vs patient’s preference: hazard ratio [HR], 0.13; 95% confidence interval [CI], 0.04 to 0.48; p=0.002) and adalimumab use was associated with higher risk of relapse (vs infliximab: HR, 4.42; 95% CI, 1.24 to 17.74; p=0.022) in CD patients. Mucosal healing was associated with lower risk of relapse (vs nonmucosal healing: HR, 0.12; 95% CI, 0.02 to 0.83; p=0.031) in UC patients. Anti-TNF re-induction was provided to 52 patients, and a response was obtained in 50 patients. However, 25 of them discontinued retreatment owing to a loss of response (n=15), the patient’s preference (n=6), and other factors (n=4). Conclusions More than 60% of IBD patients in remission under anti-TNF therapy relapsed within 5 years of treatment cessation. Anti-TNF re-induction was effective. However, half of the patients discontinued anti-TNF therapy, and 50% of these patients discontinued treatment owing to loss of response.

Background: and Purpose Epidemiologic data suggest that cluster headache (CH) is significantly associated with cigarette smoking. The aim of this study was to determine differences in features between patients with a smoking history and those who are never-smokers, using data from a prospective multicenter registry. Methods: Data used in this study were obtained from the Korean Cluster Headache Registry that collected data from consecutive patients diagnosed with CH. We compared clinical and demographic features between ever-smokers (current or former smokers) and never-smokers. Results: This study enrolled 250 patients who were diagnosed with CH, of which 152 (60.8%) were ever-smokers and 98 (39.2%) were never-smokers. The age at CH onset was significantly lower in the never-smoker group than in the ever-smoker group [27.1±12.9 years vs. 30.6± 10.9 years (mean±standard deviation), p=0.024]. Seasonal rhythmicity (58.1% vs. 44.7%, p= 0.038) and triptan responsiveness (100% vs. 85.1%, p=0.001) were higher in never-smokers, while other clinical features such as pain severity, duration, attack frequency, and associated autonomic symptoms did not differ significantly between the groups. The male-to-female ratio was markedly higher in ever-smokers (29.4:1) than in never-smokers (1.7:1). Conclusions Most of the clinical features did not differ significantly between patients with a smoking history and never-smokers. However, the age at CH onset, sex ratio, and seasonal rhythmicity were significantly associated with smoking history.

This report provides a detailed description of the methodology for ophthalmic examinations according to the Korea National Health and Nutrition Examination Survey (KNHANES) VII and VIII (from 2017 to 2021). The KNHANES is a nationwide survey which has been performed since 1998 in representatives of whole Korean population. During the KNHANES VII and VIII, in addition to the ophthalmic questionnaire, intraocular pressure measurement, visual field test, auto refractometry, axial length and optical coherence tomography measurements were included. This new survey will provide not only provide normative and pathologic ophthalmic data including intraocular pressure, refractive error, axial length, visual field and precise measurement of anterior segment, macula and optic nerve with optical coherence tomography, but also a more accurate diagnosis for major adult blindness diseases, including age-related macular degeneration, diabetic retinopathy, glaucoma, and other ocular diseases, for the national Korean population.

This report provides a detailed description of the methodology for ophthalmic examinations according to the Korea National Health and Nutrition Examination Survey (KNHANES) VII and VIII (from 2017 to 2021). The KNHANES is a nationwide survey which has been performed since 1998 in representatives of whole Korean population. During the KNHANES VII and VIII, in addition to the ophthalmic questionnaire, intraocular pressure measurement, visual field test, auto refractometry, axial length and optical coherence tomography measurements were included. This new survey will provide not only provide normative and pathologic ophthalmic data including intraocular pressure, refractive error, axial length, visual field and precise measurement of anterior segment, macula and optic nerve with optical coherence tomography, but also a more accurate diagnosis for major adult blindness diseases, including age-related macular degeneration, diabetic retinopathy, glaucoma, and other ocular diseases, for the national Korean population.

Background/Aims: Our study aimed to evaluate the long-term outcomes and risk factors forrelapse after anti-tumor necrosis factor (TNF)-α cessation in inflammatory bowel disease (IBD) patients because they are not well established. Methods: A retrospective multicenter cohort study was conducted involving patients with Crohn’s disease (CD) or ulcerative colitis (UC) from 10 referral hospitals in Korea who discontinued firstline anti-TNF therapy after achieving clinical remission. Results: A total of 109 IBD patients (71 CD and 38 UC) with a median follow-up duration of 56months were analyzed. The cumulative relapse rates at 1, 3, and 5 years were 11.3%, 46.7%, and 62.5% for CD patients and 28.9%, 45.3%, and 60.9% for UC patients. Multivariable Coxanalysis revealed that discontinuation owing to the clinician’s decision was associated with lower risk of relapse (vs patient’s preference: hazard ratio [HR], 0.13; 95% confidence interval [CI], 0.04 to 0.48; p=0.002) and adalimumab use was associated with higher risk of relapse (vs infliximab: HR, 4.42; 95% CI, 1.24 to 17.74; p=0.022) in CD patients. Mucosal healing was associated with lower risk of relapse (vs nonmucosal healing: HR, 0.12; 95% CI, 0.02 to 0.83; p=0.031) in UC patients. Anti-TNF re-induction was provided to 52 patients, and a response was obtained in 50 patients. However, 25 of them discontinued retreatment owing to a loss of response (n=15), the patient’s preference (n=6), and other factors (n=4). Conclusions More than 60% of IBD patients in remission under anti-TNF therapy relapsed within 5 years of treatment cessation. Anti-TNF re-induction was effective. However, half of the patients discontinued anti-TNF therapy, and 50% of these patients discontinued treatment owing to loss of response.