Sarcopenia can contribute to negative outcomes in patients with various lung diseases. However, whether sarcopenia affects prognosis in patients with idiopathic pulmonary fibrosis (IPF) has not been reported. Simple measures of muscle mass, derived from chest computed tomography (CT), are increasingly being used to identify patients with sarcopenia. We hypothesized that skeletal muscle mass could be a predictor of prognosis in IPF patients. We retrospectively evaluated 180 patients diagnosed with IPF between January 2010 and December 2015 at a tertiary care hospital in South Korea. We measured thoracic muscle volume by using the cross-sectional area (CSA) of the pectoralis, paraspinal, serratus, and latissimus muscles at the 4th vertebral region (T4CSA) and the erector spinae muscle (ESMCSA) at the 12th vertebral region. CT scans at the time of diagnosis were used for analysis and respective CSA were divided by height squared to normalize for stature. Survival times were estimated with the Kaplan–Meier method and compared with the log-rank test. Multivariate Cox proportional hazards models were performed to investigate relationships between clinical parameters and mortality. Male patients in the lowest quartile of T4CSA divided by height squared (m2) (T4MI) and in the lowest quartile of ESMCSA divided by height squared (m2) (T12MI) were more likely to have higher Gender-Age-Physiology Index scores (T4MI, 3.3 ± 1.3 vs 4.0 ± 1.6, P = 0.012; T12MI, 3.2 ± 1.3 vs 4.1 ± 1.6, P = 0.002). Male patients in the lowest quartile of T4MI exhibited a significantly lower survival rate (P = 0.035). After multivariate Cox proportional hazards analysis, T4MI was a significant risk factor for all-cause mortality (HR, 0.955; 95% CI, 0.913–0.998; P = 0.041), whereas T12MI was not (HR, 0.980; 95% CI, 0.856–1.121; P = 0.766). Low skeletal mass normalized for stature at the level of 4th vertebrae which can be acquired by quantifying thoracic skeletal muscle on single-slice axial chest CT, may be a strong risk factor for all-cause mortality in patients with IPF. The research protocol was approved by the Institutional Review Board of Severance Hospital, South Korea (IRB No.4–2018-0454).

Background: Diagnostic cutoff points for sarcopenia in chest computed tomography (CT) have not been established although CT is widely used for investigating skeletal muscles. This study aimed to determine reference values for sarcopenia of thoracic skeletal muscles acquired from chest CT scans and to analyse variables related to sarcopenia using the cutoff values determined in a general Asian population.Methods: We retrospectively reviewed chest CT scans of 4470 participants (mean age 54.8 ± 9.9 years, 65.8% male) performed at a check‐up centre in South Korea (January 2016–August 2017). To determine cutoffs, 335 participants aged 19–39 years (mean age 35.2 ± 3.6 years, 75.2% male) were selected as the healthy and younger reference group, and 4135 participants aged ≥40 years (mean age 56.4 ± 8.4 years, 65.1% male) were selected as the study group. We measured the following: cross‐sectional area (CSA) of the pectoralis, intercostalis, paraspinal, serratus, and latissimus muscles at the 4^th vertebral region (T4_CSA); T4_CSA divided by height² (T4MI); pectoralis muscle area (PM_CSA); and PM_CSA divided by height² (PMI) at the 4^th vertebral region. Sarcopenia cutoff was defined as sex‐specific values of less than −2 SD below the mean from the reference group.Results: In the reference group, T4_CSA, T4MI, PM_CSA, and PMI cutoffs for sarcopenia were 100.06cm², 33.69cm²/m², 29.00cm², and 10.17cm²/m² in male, and 66.93cm², 26.01cm²/m², 18.29cm², and 7.31cm²/m² in female, respectively. The prevalence of sarcopenia in the study group measured with T4_CSA, T4MI, PM_CSA and PMI cutoffs were 11.4%, 8.7%, 8.5%, and 10.1%, respectively. Correlations were observed between appendicular skeletal mass divided by height² measured by bioelectrical impedance analysis (BIA) and T4_CSA (r = 0.82; P < 0.001)/T4MI (r = 0.68; P < 0.001), and ASM/height² measured by BIA and PM_CSA (r = 0.72; P < 0.001)/PMI (r = 0.63; P < 0.001). In the multivariate logistic regression models, sarcopenia defined by T4_CSA/T4MI were related to age [odds ratio (95% confidence interval), P‐values: 1.09 (1.07–1.11), <0.001/1.05 (1.04–1.07), <0.001] and diabetes [1.60 (1.14–2.25), 0.007/1.47 (1.01–2.14), 0.043]. Sarcopenia defined by PM_CSA/PMI were related to age [1.09 (1.08–1.10), <0.001/1.05 (1.03–1.06), <0.001], male sex [0.23 (0.18–0.30), <0.001/0.47 (0.32–0.71), <0.001], diabetes [2.30 (1.73–3.05), <0.001/1.63 (1.15–2.32), 0.007], history of cancer [2.51 (1.78–3.55), <0.001/1.61 (1.04–2.48), 0.033], and sufficient physical activity [0.67 (0.50–0.89), 0.007/0.74 (0.56–0.99), 0.042].Conclusions: The reference cutoff values of a general population reported here will enable sex‐specific standardization of thoracic muscle mass quantification and sarcopenia assessment.

Rationale: In recent decades, diagnosis and treatment recommendations for idiopathic pulmonary fibrosis (IPF) have changed. In Korea, the average life expectancy has increased, unmet healthcare needs have been reduced, and the number of computed tomographic examinations performed has nearly doubled. The Korean Interstitial Lung Disease Study Group conducted a nationwide cohort study for idiopathic interstitial pneumonia, including IPF, and established a registry for IPF. Objectives: Using study data collected by the study group, this study aimed to evaluate longitudinal changes in clinical features, diagnosis, treatment, and mortality and analyze the extent to which changes in medication usage affected IPF-associated mortality. Methods: The study population included newly diagnosed patients with IPF from a cohort study (January 2002 to September 2008, n = 1,839, 2008 group) and prospective registry (January 2012 to August 2018, n = 1,345, 2018 group). Survival curves were estimated using the Kaplan-Meier method, and Cox regression models were used to identify mortality-associated risk factors in each group. Results: The 2018 group was younger, had fewer symptoms, had less honeycombing, underwent more serologic autoimmune marker and pulmonary function tests, had higher oxygen partial pressure and lower carbon dioxide partial pressure values, was less frequently diagnosed by surgical biopsy, and had better survival than the 2008 group. Steroid use and conservative care declined, whereas N-acetylcysteine use increased in this group. Antifibrotic agents were used in only the 2018 group. In the 2008 group, N-acetylcysteine was associated with lower mortality, whereas conservative care was associated with higher mortality. In the 2018 group, the use of antifibrotic agents was associated with lower mortality, and steroid use was associated with higher mortality. The survival rates in the 2008 and 2018 non-antifibrotic agent subgroups were similar. Conclusions: This study analyzed national IPF cohort data spanning 17 years. In clinical practice, the IPF diagnosis was made earlier, steroid and immunosuppressive agent use was reduced, and antifibrotic agents were administered. The survival of patients with IPF has improved over the decades, and antifibrotic use was consistently associated with improved survival. Clinical trial registered with clinicaltrials.gov (NCT04160715).

Health outcomes of the elderly vary between rural and urban areas. Sarcopenia is diagnosed as loss of muscle strength or impaired physical performance, namely “low muscle function” and low muscle mass. Outcomes of low muscle mass and low muscle function are not equal. This study aimed to investigate the prevalence of low muscle mass, low muscle function, and sarcopenia in rural and urban populations and to determine whether regional differences were associated with each of these components. Participants aged ≥ 69 years (n = 2354) were recruited from three urban districts and one rural district in Korea. Low muscle mass was defined by appendicular lean mass using bioelectrical impedance analysis. Low muscle function was defined by handgrip strength and 5-chair stand test. Sarcopenia was defined as low muscle mass plus low muscle function. The prevalence of low muscle function (53.7% vs. 72.8%), and sarcopenia (16.3% vs. 24.4%) were higher in the rural elderly population. Rural residence was associated with low muscle function (OR 1.63; 95% CI 1.13–2.37, P = 0.009), but not with low muscle mass (OR 0.58; 95% CI 0.22–1.54, P = 0.271) or with sarcopenia (OR 1.13; 95% CI 0.63–2.00, P = 0.683). Interventions to detect and improve low muscle function in rural elderly population are needed.

Purpose: Previous studies have shown that progressive forms of non-alcoholic fatty liver disease (NAFLD) occur frequently in patients with obstructive lung disease (OLD). However, few studies have written about this relationship. This study aimed to investigate the relationship between OLD and NAFLD. Subjects and methods: The Korea National Health and Nutrition Examination Survey is a national population-based, cross-sectional surveillance program that was initiated to assess the health and nutritional status of the Korean population. From 2007 to 2010, 11,738 subjects were enrolled. The subjects were defined as having NAFLD when they had scores higher than -0.640 in a NAFLD liver fat score prediction model, which was a previously validated prediction score. Individuals with forced expiratory volume in one second/forced vital capacity <0.7 were considered to have OLD. The subjects were divided into non-OLD and OLD groups and non-NAFLD and NAFLD groups. All analyses were performed using sample weighting using the complex samples plan. Results: The prevalences of NAFLD and OLD were 30.2% and 8.9%, respectively. Although not statistically significant, subjects in the NAFLD group involved a higher tendency of having OLD than did those in the non-NAFLD group (8.5% vs 10.0%, respectively, P=0.060). Subjects with OLD showed a higher tendency to have NAFLD than non-OLD subjects (30.0% vs 33.7%, respectively, P=0.060). NAFLD subjects were at higher odds of OLD (odds ratio=1.334; 95% confidence interval=1.108–1.607, P=0.002) than non-NAFLD subjects, after adjusting for age, sex, and smoking history. OLD subjects were at higher odds of NAFLD (odds ratio=1.556; 95% confidence interval=1.288–1.879, P<0.001) than non-OLD subjects, after adjusting for age, sex, and smoking history. Conclusion: This study showed that NAFLD is related to OLD. Clinicians should be aware of possible liver comorbidities in OLD patients and that extrahepatic disease in NAFLD patients may vary more than previously thought.