Erratum: Correction of Author's Affiliation in the Article "Changing Patterns of Medical Visits and Factors Associated With No-show in Patients With Rheumatoid Arthritis During COVID-19 Pandemic".

This corrects the article on p. e423 in vol. 35, PMID: 33316859.

Modifying surface charge density of thermoplastic nanofluidic biosensors by multivalent cations within the slip plane of the electric double layer.

Thermoplastic nanofluidic devices are promising platforms for sensing single biomolecules due to their mass fabrication capability. When the molecules are driven electrokinetically through nanofluidic networks, surface charges play a significant role in the molecular capture and transportation, especially when the thickness of the electrical double layer is close to the dimensions of the nanostructures in the device. Here, we used multivalent cations to alter the surface charge density of thermoplastic nanofluidic devices. The surface charge alteration was done by filling the device with a multivalent ionic solution, followed by withdrawal of the solution and replacing it with KCl for conductance measurement. A systematic study was performed using ionic solutions containing Mg2+ and Al3+ for nanochannels made of three polymers: poly(ethylene glycol) diacrylate (PEGDA), poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC). Overall, multivalent cations within the slip plane decreased the effective surface charge density of the device surface and the reduction rate increased with the cation valency, cation concentration and the surface charge density of thermoplastic substrates. We demonstrated that a 10-nm diameter in-plane nanopore formed in COC allowed translocation of λ-DNA molecules after Al3+ modification, which is attributed to the deceased viscous drag force in the nanopore by the decreased surface charge density. This work provides a general method to manipulate surface charge density of nanofluidic devices for biomolecule resistive pulse sensing. Additionally, the experimental results support ion-ion correlations as the origin of charge inversion over specific chemical adsorption.

Maternal and paternal effects on hyperuricaemia: a cross-sectional study from the seventh Korean National Health and Nutrition Examination Survey.

OBJECTIVE: As the heritability of hyperuricaemia remains largely unexplained, we analysed the association between parental and offspring hyperuricaemia at the phenotype level. METHODS: This cross-sectional study included data on 2373 offspring and both-parent pairs from the seventh Korean National Health and Nutrition Examination Survey. Logistic regression and generalised estimating equation analysis were used to evaluate the association between offspring and parental hyperuricaemia adjusting for metabolic risk factors and alcohol intake. RESULTS: Both maternal and paternal hyperuricaemia were associated with offspring hyperuricaemia among teenagers, but from the age of 20 years, a strong association was observed between offspring and paternal, rather than, maternal hyperuricaemia, and this could not be explained by metabolic risk factors such as obesity. However, there was a positive interaction between offspring alcohol intake and parental hyperuricaemia, and there was a stronger association between terciles of offspring alcohol intake and hyperuricaemia in the presence of parental hyperuricaemia: T1 (reference), T2 odds ratio (OR) 1.1 (0.3-4.6), and T3 OR 3.3 (1.4-7.9) (P for trend .017) vs. T1 (reference), T2 OR 0.7 (0.3-1.9), and T3 OR 1.1 (0.6-2.2) (P for trend .974). CONCLUSION: These results suggest a gene-environment interaction, especially with respect to alcohol intake for hyperuricaemia in Korean adults.

Efficacy and tolerability of febuxostat in gout patients on dialysis.

BACKGROUND: There are no sufficient data available on the use of febuxostat in patients undergoing dialysis. AIM: To investigate the efficacy and tolerability of febuxostat in gout patients on dialysis. METHODS: We retrospectively reviewed clinical and laboratory data available from a referral centre from January 2012 to December 2018. We included gout patients who initiated febuxostat during dialysis. Data regarding serum uric acid levels before and after the febuxostat treatment and clinical information such as gout attack after febuxostat initiation, as well as adverse events involving febuxostat treatment, were obtained from medical records. RESULTS: Among 62 patients who were treated with febuxostat for over 3 months, 45 were undergoing haemodialysis (HD) and 17 were undergoing peritoneal dialysis (PD). The mean serum uric acid level was significantly reduced 3 months after treatment (3.71 ± 1.32 mg/dL) compared with that at the pretreatment level (9.36 ± 2.06 mg/dL) (P < 0.001). The serum uric acid level was observed to be significantly reduced at 3 months in both HD and PD patients and subsequently remained at a significantly reduced level for 12 months. Of the 62 patients, only two stopped febuxostat due to its adverse effects. Initial dose of 80 mg/day was associated with higher adverse events compared to dose of 20-40 mg/day (odds ratio 8.25, 95% confidence interval 1.90-35.97, P = 0.006). CONCLUSIONS: Febuxostat is efficacious and well tolerated in gout patients on dialysis. Febuxostat taken at dose of 20-40 mg/day might be appropriate initial dose in patients undergoing dialysis.

Clinically amyopathic dermatomyositis presenting with isolated facial edema complicated by acute respiratory failure: a case report.

BACKGROUND: In clinically amyopathic dermatomyositis, the hallmark cutaneous manifestations are the key to diagnosis. We report a case of clinically amyopathic dermatomyositis which presented with facial edema as the sole cutaneous manifestation and was later complicated by acute respiratory failure leading to death. CASE PRESENTATION: A 58-year-old woman presented with edema of the face that had developed approximately one year ago. There was no weakness in the extremities, and the serum creatine kinase level was within normal range. On MRI, there was diffuse edematous change in the bilateral masticator and extra-ocular muscles, accompanied by subcutaneous fat infiltration in the face. A shared decision was made to defer muscle biopsy in the facial muscles. The facial swelling almost resolved with medium-dose glucocorticoid therapy but relapsed in days at glucocorticoid doses lower than 15 mg/day. Combination therapy with either azathioprine, mycophenolate, or methotrexate was not successful in maintaining clinical remission, and the swelling became more severe after relapses. A US-guided core-needle biopsy was subsequently performed in the right masseter muscle. On pathologic examination, there was a patchy CD4 + T cell-dominant lymphoplasmacytic infiltration in the stroma, necrosis of the myofibrils and prominent perifascicular atrophy. Based on those findings, a diagnosis of clinically amyopathic dermatomyositis was made. Therapy with gamma-globulin was not effective in maintaining remission. In the sixth week after starting rituximab, she presented to emergency room with altered mental state from acute respiratory failure. Despite treatment with antibiotics, glucocorticoid pulse, cyclosporin, and polymyxin B-immobilized fiber column direct hemoperfusion, she died three weeks later from persistent hypoxemic respiratory failure. CONCLUSIONS: This case showed the full spectrum and severity of internal organ involvement of dermatomyositis, although the patient presented exclusively with subcutaneous edema limited to the head. The prognosis may be more closely associated with a specific auto-antibody profile than the benign-looking initial clinical manifestation. Close follow-up of lung involvement with prophylactic treatment for Pneumocystis pneumonia and prompt implementation of emerging therapeutic regimens may improve the outcome.

Coronavirus Disease 19 (COVID-19) complicated with pneumonia in a patient with rheumatoid arthritis receiving conventional disease-modifying antirheumatic drugs.

In December 2019, numerous coronavirus disease 2019 (COVID-19) cases were reported in Wuhan, China, which has since spread throughout the world. However, its impact on rheumatoid arthritis (RA) patients is unknown. Herein, we report a case of COVID-19 pneumonia in a 61-year-old female RA patient who was receiving conventional disease-modifying antirheumatic drugs (cDMARDs). The patient presented with a 4-day history of myalgia and febrile sensation. COVID-19 was confirmed by real-time polymerase chain reaction (PCR). Chest X-ray showed increased opacity on the right lower lung area, and C-reactive protein level was slightly elevated. The patient was treated with antiviral agents (lopinavir/ritonavir), and treatment with cDMARDs was discontinued except hydroxychloroquine. Her symptoms and laboratory results gradually improved. Three weeks later, real-time PCR for COVID-19 showed negative conversion, and the patient was discharged without any complications.

Changing Patterns of Medical Visits and Factors Associated with No-show in Patients with Rheumatoid Arthritis during COVID-19 Pandemic.

BACKGROUND: The main barrier to the effective rheumatoid arthritis (RA) therapy is poor adherence. Coronavirus disease 2019 (COVID-19) pandemic have led to a significant change in the pattern and the number of medical visits. We assessed changing patterns of medical visits and no-show, and identified factors associated with no-show in patients with RA during COVID-19 pandemic. METHODS: RA patients treated with disease-modifying antirheumatic drugs at least 6 months who had been in remission or those with mild disease activity were observed for 6 months from February to July 2020. No-show was defined as a missed appointment that was not previously cancelled by the patient and several variables that might affect no-show were examined. RESULTS: A total of 376 patients and 1,189 appointments were evaluated. Among 376 patients, 164 patients (43.6%) missed appointment more than one time and no-show rate was 17.2% during COVID-19 pandemic. During the observation, face-to-face visits gradually increased and no-show gradually decreased. The logistic regression analysis identified previous history of no-show (adjusted odds ratio [OR], 2.225; 95% confidence interval [CI], 1.422-3.479; P < 0.001) and fewer numbers of comorbidities (adjusted OR, 0.749; 95% CI, 0.584-0.961; P = 0.023) as the independent factors associated with no-show. CONCLUSION: Monthly analysis showed that the no-show rate and the pattern of medical visits gradually changed in patients with RA during COVID-19 pandemic. Moreover, we found that previous history of no-show and fewer numbers of comorbidities as the independent factors associated with no-show.

Dietary and nutritional factors associated with hyperuricemia: The seventh Korean National Health and Nutrition Examination Survey.

BACKGROUND AND OBJECTIVES: The association of dietary and nutritional factors with hyperuricemia and gout is well-known in Western populations. The present study aimed to examine the association of dietary and nutritional factors with hyperuricemia among Korean adults. METHODS AND STUDY DESIGN: This cross-sectional study included 10,175 participants from the seventh Korean National Health and Nutrition Examination Survey 2016-2017. Dietary information was collected using a single 24-hour recall method, and nutritional information was derived from the 9th Korean Food Composition Table. The associations between serum uric acid and intake of meat, seafoods, nuts, and legumes, sugar-sweetened products, dairy products, alcohol, sodium, vitamin A, vitamin B1, vitamin C, and dietary fiber were analyzed using linear regression analysis adjusting for confounding variables. The association with hyperuricemia was analyzed using logistic regression analysis. All analyses were weighted by the sampling design. RESULTS: Alcohol intake was associated with serum uric acid in both men and women. In men, the highest quartile of alcohol intake was associated with a 1.5-times higher prevalence of hyperuricemia (odds ratio [OR] 1.5, 95% confidence interval [CI] 1.16-1.95), while vitamin C and dietary fiber intakes were found to be inversely associated with hyperuricemia. For vitamin C and dietary fiber intake, the ORs for a quartile increase were 0.93 (95% CI 0.86-0.99) and 0.92 (95% CI 0.85-0.99), respectively. CONCLUSIONS: The associations between vitamin C, dietary fiber and alcohol intakes and hyperuricemia in men support the Dietary Approach to Stop Hypertension (DASH)-based approach and attention to alcohol intake for managing hyperuricemia in Korean men.

Inhibition potential of phenolic constituents from the aerial parts of Tetrastigma hemsleyanum against soluble epoxide hydrolase and nitric oxide synthase.

The aerial parts of Tetrastigma hemsleyanum (APTH) have been used as a functional tea in China. The purpose of the current study was to identify the bioactive constituents with inhibitory activity against soluble epoxide hydrolase (sEH) and inducible nitric oxide synthase (iNOS), which are jointly considered potential therapeutic targets for vascular system diseases. In the present study, 39 compounds (1-39) were isolated from the APTH. Among them, compounds 8, 10, 12, 16, 17, 19, and 32 displayed potential activities, with IC50 values ranging from 4.5 to 9.5 µM, respectively, and all in non-competitive inhibition mode. Compounds 5, 10, 12, 19, and 32 displayed potent iNOS inhibitory effects, with IC50 values ranging from 15.6 to 47.3 µM. The results obtained in this work contribute to a better understanding of the pharmacological activities of T. hemsleyanum and its potential application as a functional food.

Slow-Binding Inhibition of Tyrosinase by Ecklonia cava Phlorotannins.

Tyrosinase inhibitors improve skin whitening by inhibiting the formation of melanin precursors in the skin. The inhibitory activity of seven phlorotannins (1-7), triphlorethol A (1), eckol (2), 2-phloroeckol (3), phlorofucofuroeckol A (4), 2-O-(2,4,6-trihydroxyphenyl)-6,6'-bieckol (5), 6,8'-bieckol (6), and 8,8'-bieckol (7), from Ecklonia cava was tested against tyrosinase, which converts tyrosine into dihydroxyphenylalanine. Compounds 3 and 5 had IC50 values of 7.0 ± 0.2 and 8.8 ± 0.1 µM, respectively, in competitive mode, with Ki values of 8.2 ± 1.1 and 5.8 ± 0.8 µM. Both compounds showed the characteristics of slow-binding inhibitors over the time course of the enzyme reaction. Compound 3 had a single-step binding mechanism and compound 5 a two-step-binding mechanism. With stable AutoDock scores of -6.59 and -6.68 kcal/mol, respectively, compounds 3 and 5 both interacted with His85 and Asn260 at the active site.

Long-term adherence and persistence with febuxostat among male patients with gout in a routine clinical setting.

Objectives: To assess long-term adherence and persistence to febuxostat (FBX) and factors that might contribute to non-adherence and non-persistence to FBX in male patients with gout during a 3-year period. Methods: Adherence to FBX was assessed by the clinic nurses through pill counts at the scheduled visits and non-adherence was defined as less than 80% of the prescribed dose taken. Non-persistence was defined as discontinuation of FBX longer than 60 days. Results: A total of 220 patients were recruited. The percentage of adherence and persistence was 71.8% and 80.9% at 1 year, 65.5% and 68.2% at 2 years and 58.2% and 56.4% at 3 years, respectively. The logistic regression analysis identified high income status, current smoking, absence of hypertension and previous history of non-persistence with urate-lowering therapy (ULT) as the independent factors associated with non-adherence, and the unmarried, absence of hypertension and previous history of non-persistence with ULT as the independent factors associated with non-persistence. Conclusion: Variable risk factors that are correlated with poor adherence or persistence and easily assessed can be used to identify patients at a particular risk of poor adherence or persistence.

Adherence with urate-lowering therapies among male patients with gout in a routine clinical setting.

OBJECTIVES: To assess adherence (compliance and persistence) and factors that might contribute to nonadherence to urate-lowering therapies (ULT) in patients with gout in a routine clinical setting. METHODS: This prospective observational cohort study was conducted in the rheumatology center of a local tertiary hospital. A total of 132 male adults aged 75 years or younger who were incidentally diagnosed with gout were included. Adherence to ULT was assessed by the clinic nurses through pill counts. RESULTS: Of the 132 patients, 94 (71.2%) was compliant and 81 (61.4%) was persistent with ULT. The logistic regression analysis revealed that the absence of chronic kidney disease (CKD) and the previous history of non-persistence with ULT are the independent factors associated with noncompliance and the absence of CKD is an independent factor associated with non-persistence. The average serum urate levels of the noncompliant (p = 0.001) and non-persistent (p = 0.002) patients were significantly higher than those of the compliant and persistent patients. CONCLUSIONS: The absence of CKD and the previous history of non-persistence of ULT that are correlated with poor adherence and easily assessed can be used to identify patients at a particular risk of poor adherence.

Obesity, metabolic abnormality, and knee osteoarthritis: a cross-sectional study in Korean women.

BACKGROUND: This study aimed to analyze the association between knee osteoarthritis and four body size phenotypes defined by the presence or absence of metabolic abnormality and obesity. MEHODS: This was a cross-sectional study using data from 1,549 female participants of the Fifth Korean National Health and Nutrition Examination Survey. Knee osteoarthritis was defined as a Kellgren-Lawrence grade of ≥ 2. Metabolically abnormal state was defined as presence of more than one abnormality among five metabolic risk factors. Obesity was defined using body mass index. Participants were grouped into one of the four body size phenotypes: metabolically healthy normal weight (MHNW), metabolically abnormal but normal weight (MANW), metabolically healthy obesity (MHO), and metabolically abnormal obesity (MAO). RESULTS: The distribution of each body size phenotype was as follows: MHNW 54.7%, MANW 30.7%, MHO 4.3%, and MAO 10.3%. Prevalence of symptomatic knee osteoarthritis was higher in MANW than in MHNW, and in MAO than in MHO. In multivariable analysis, the association between symptomatic knee osteoarthritis and the body size phenotypes was as follows (OR [95% CI]): MHNW 1.00 (reference), MANW 1.54 (1.15-2.07), MHO 1.61 (0.83-3.13), and MAO 3.47 (2.35-5.14). CONCLUSIONS: Obesity showed closest association with knee osteoarthritis when accompanied by metabolic abnormality.

Knee osteoarthritis is associated with increased prevalence of vertebral fractures despite high systemic bone mineral density: a cross-sectional study in an Asian population.

OBJECTIVES: This study aimed to evaluate the relationship between radiographic knee osteoarthritis and vertebral fractures (VFs) in an Asian population. METHODS: This cross-sectional study involved data from 1,829 participants of the Fifth Korean National Health and Nutrition Examination Survey. Radiographic knee osteoarthritis was defined as Kellgren-Lawrence (KL) grades ≥ 2. Prevalent VF was defined as a loss of ≥ 4 cm of height from the peak height. BMD was measured using dual-energy X-ray absorptiometry, in the lumbar spine and femoral neck. RESULTS: In both sexes, the prevalence of VFs increased with age, and was higher in the knee osteoarthritis group than in the control group (in men 13.2 % in osteoarthritis group and 7.9 % in control group; in women 27.7 % in osteoarthritis group and 14.7 % in control group). Age-adjusted BMD at the lumbar spine and femoral neck was significantly higher in the knee osteoarthritis group. In multivariable analysis, KL grade 4 was significantly associated with vertebral fractures in men. In women, there was a significant trend for a positive association between KL grades and vertebral fractures. CONCLUSIONS: Despite high systemic BMD, knee osteoarthritis was positively associated with VFs. These results suggest that bone quality, and consequently bone strength, may be decreased at the systemic level in knee osteoarthritis.

Sarcopenic obesity is more closely associated with knee osteoarthritis than is nonsarcopenic obesity: a cross-sectional study.

OBJECTIVE: Sarcopenic obesity is a body composition category in which obesity is accompanied by low skeletal muscle mass, offsetting the increase in body weight caused by increased adipose tissue. The purpose of this study was to analyze the association between knee osteoarthritis (OA) and 4 different categories of body composition: normal, sarcopenic nonobesity, nonsarcopenic obesity, and sarcopenic obesity. METHODS: This was a cross-sectional study using the data from 2,893 participants in the Fifth Korean National Health and Nutrition Examination Survey. Radiographic knee OA was defined as a Kellgren/Lawrence grade of ≥2. Appendicular skeletal muscle mass (ASM) and whole-body fat mass were measured using dual x-ray absorptiometry. Sarcopenia was defined as a skeletal muscle mass index (ASM/body weight [%]) below -2SD of the value in sex-matched young reference groups. Nonsarcopenic obesity was defined as a body mass index (BMI) ≥27.5 kg/m(2) . RESULTS: The prevalence of each body composition category was as follows: 83.5% normal, 4.3% sarcopenic nonobesity, 9.2% nonsarcopenic obesity, and 3.0% sarcopenic obesity. Compared with nonsarcopenic obesity participants, participants with sarcopenic obesity were significantly older, had lower ASM, higher whole-body fat mass, and higher waist circumference. However, there was no significant difference in body weight or BMI. In multivariate analysis, sarcopenic obesity was more closely associated with radiographic knee OA (OR 3.51 [95% confidence interval (95% CI) 2.15-5.75]) than was nonsarcopenic obesity (OR 2.38 [95% CI 1.80-3.15]). Sarcopenic nonobesity showed no significant association with knee OA. CONCLUSION: Sarcopenic obesity was more closely associated with knee OA than was nonsarcopenic obesity, although both groups had equivalent body weight. This finding supports the importance of the systemic metabolic effect of obesity in knee OA.

Endovascular treatment of Takayasu arteritis in a middle-aged woman with syncope and limb claudication: a case report.

Takayasu arteritis (TA) is a disease that causes inflammation and stenosis of medium to large blood vessels. We report a case of a 50-year-old female patient with newly developed hypertension, syncope, and claudication of the extremities. Total occlusion of the left subclavian artery at the origin was found and significant stenosis of the right common iliac artery was revealed by hemodynamic analysis. She was successfully treated with percutaneous angioplasty for multiple peripheral arterial diseases and was finally diagnosed with TA. In consultation with a rheumatologist, medical treatment for TA was initiated, the patient's hypertension disappeared, and her claudication symptoms improved.

Association between knee osteoarthritis and mortality: a serial propensity score-matched cohort study.

BACKGROUND/AIMS: The association between symptomatic knee osteoarthritis (OA) and higher cardiovascular disease (CVD) mortality is established; however, findings from studies that utilized regression analysis were limited, attributed to the strong association between OA and metabolic risk factors. This study aimed to evaluate the association between knee OA and mortality through propensity score matching. METHODS: This was a cohort study including Korean National Health and Nutrition Examination Survey (2010-2013) participants aged ≥ 50 years. By linking the survey data to cause of death data (through 2019) from Statistics Korea, mortality and cause-specific mortality data were obtained. Radiographic knee OA (ROA) was defined as bilateral Kellgren-Lawrence grade ≥ 2. Propensity score matching (1:1) was conducted between asymptomatic ROA, knee pain, and symptomatic ROA groups and normal groups, balancing the confounding factors. Time to death was analyzed using Cox proportional hazard modeling. RESULTS: A higher CVD mortality was observed in the symptomatic ROA group, but not in others; the risk estimates were asymptomatic ROA (hazard ratio [HR] 1.12; 95% confidence interval [CI] 0.77-1.65), knee pain (HR 0.61; 95% CI 0.27-1.38), and symptomatic ROA (HR 1.39; 95% CI 0.89-2.17). No association was found between the all-cause/cancer mortality and other groups. CONCLUSION: When propensity score matching controls metabolic risk factor imbalances, the association between symptomatic knee OA and higher CVD mortality was weaker compared to results of prior studies that used regression adjustment. The results may be more precise estimates of the total risk of knee OA for mortality in Koreans.

The clinical efficacy of a mixture of ivy leaf extract and coptidis rhizome in patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with poor prognosis and cough is the one of most common and major symptoms in IPF. The aim of this study was to evaluate the clinical efficacy of a Mixture of Ivy Leaf Extract and Coptidis rhizome (Synatura®) in patients with IPF. This was a prospective, open-label, single-center, and single-arm study in Korea from October 2019 to September 2020. IPF patients with chronic bronchitis were enrolled. Between baseline and eight weeks after use of Synatura®, clinical measures regarding cough and health-related quality of life, and the systemic inflammatory markers was prospectively collected. Thirty patients were enrolled. Median age was 73 years and 86.7% were men. The median gender-age-pulmonary function stage of IPF was 3. Baseline total score of Leicester cough questionnaire (LCQ) and St. George respiratory questionnaire (SGRQ) were 104.5 and 30.59 respectively. After eight weeks, there was no significant improvement in LCQ (16.8 [15.6-19.1] vs 17.5 [15.2-18.9], P = .772) and SGRQ (30.6 [19.4-37.8] vs 29.9 [19.6-41.8], P = .194) scores. Also, there was no significant difference of systemic inflammatory markers. In analysis of minimal clinically important differences (MCID), one third (33.3%) patients fulfilled the criteria of MCID (1.3) in LCQ scores and median differences was 14 (range: 10-18). In terms of SGRQ, 6 patients (20%) reached MCID (4.0) without significant predictive factors. In our study, use of Synatura® during 8 weeks improved cough-specific life quality in one third patients with IPF. Large-scale, randomized, double-blind, and placebo-controlled clinical trials are needed.

Prevalence and clinical impacts of obstructive sleep apnea in patients with idiopathic pulmonary fibrosis: A single-center, retrospective study.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an interstitial lung disease with chronic, progressive lung fibrosis with a poor prognosis. Recent studies have reported a high prevalence of obstructive sleep apnea (OSA) in IPF patients and an association with poor prognosis. This study aimed to evaluate the prevalence, risk factors, and clinical effects on mortality of OSA in patients with IPF. METHODS: Clinical data were retrospectively analyzed in 167 patients with IPF at Haeundae-Paik Hospital, Republic of Korea. A type 4 portable device was used to monitor OSA, and an apnea-hypopnea index of 5 events per sleep hour and above was diagnosed as OSA. RESULTS: The mean follow-up period and age were 26.9 months and 71.4 years, respectively, with male predominance. OSA was confirmed in 108 patients (64.7%). Mild OSA was the most common (62.1%). Independent risk factors for OSA in the multivariate logistic regression analysis were age (odds ratio [OR] 1.07, 95% confidence interval [CI] 1.02-1.13, p = 0.007), body weight (OR 1.05, 95% CI 1.02-1.09, p = 0.002), and risk based on the Berlin questionnaire (OR 2.76, 95% CI 1.12-6.80, p = 0.028). Shorter six-minute walk distance (6MWD) (hazard ratio [HR] 1.00, 95% CI: 1.00-1.00, p < 0.001), acute exacerbation (AE) (HR 13.83, 95% CI: 5.71-33.47, p < 0.001), and higher percentage of cumulative time with oxygen saturation below 90% in total sleep time (HR 1.08, 95% CI: 1.02-1.14, p = 0.007) were risk factors for mortality in IPF patients in the Cox regression analysis. CONCLUSION: Approximately two-thirds of the IPF patients had OSA. Older age, higher body weight, and high risk based on the Berlin questionnaire were independent risk factors for OSA in IPF patients. Shorter 6MWD, experience of AE, and night hypoxemia during sleep were associated with a higher risk of mortality in patients with IPF.

Transbronchial Lung Cryobiopsy for Diagnosing Interstitial Lung Disease: A Retrospective Single-Center Experience.

BACKGROUND: An accurate diagnosis in patients with interstitial lung diseases (ILDs) by multidisciplinary discussion (MDD) based on histopathologic information is essential for optimal treatment. Transbronchial lung cryobiopsy (TBLC) has increasingly been used as a diagnostic alternative to surgical lung biopsy. This study aimed to evaluate the appropriate methods of TBLC in patients with ILD in Korea. METHODS: A total of 27 patients who underwent TBLC were included. TBLC procedure details and clinical MDD diagnosis using TBLC histopathologic information were retrospectively analyzed. RESULTS: All procedures were performed under general anesthesia with the fluoroscopic guidance in the operation room using flexible bronchoscopy and endobronchial balloon blocker. The median procedure duration was less than 30 minutes, and the median number of biopsies per participant was 2. Most of the bleeding after TBLC was not severe, and the rate of pneumothorax was 25.9%. The most common histopathologic pattern was alternative (48.2%), followed by indeterminate (33.3%) and usual interstitial pneumonia (UIP)/probable UIP (18.5%). In the MDD after TBLC, the most common diagnosis was idiopathic pulmonary fibrosis (33.3%), followed by smoking-related ILD (25.9%), nonspecific interstitial pneumonia (18.6%), unclassifiable-ILD (14.8%), and others (7.4%). CONCLUSION: This first single-center experience showed that TBLC using a flexible bronchoscopy and endobronchial balloon blocker with the fluoroscopic guidance under general anesthesia may be a safe and adequate diagnostic method for ILD patients in Korea. The diagnostic yield of MDD was 85.2%. Further studies are needed to evaluate the diagnostic yield and confidence of TBLC.