Distinct profile and prognostic impact of body composition changes in idiopathic pulmonary fibrosis and idiopathic pleuroparenchymal fibroelastosis. Sci Rep. 2018;8:14074. [PMID: 30232390 PMCID: PMC6145941 DOI: 10.1038/s41598-018-32478-z]

Body mass index and weight loss as risk factors for poor outcomes in patients with idiopathic pulmonary fibrosis: a systematic review and meta-analysis

OBJECTIVE

The association between nutritional status and prognosis of idiopathic pulmonary fibrosis (IPF) remains unclear. This systematic review and meta-analysis aimed to explore the effect of body mass index (BMI) and weight loss on the prognosis of IPF patients.

METHODS

We accumulated studies on IPF, BMI, and weight loss from databases including PubMed, Embase, Web of science, Scopus, Ovid and Cochrane Library up to 4 August 2023. Using Cox proportional hazard regression model for subgroup analysis, hazard ratio (HR) and 95% confidence intervals (CI) for BMI in relation to mortality, acute exacerbation (AE), and hospitalization in IPF patients were calculated, and HR, odds ratio (OR), and 95% CI for weight loss corresponding to IPF patient mortality were assessed. Sensitivity analysis was peformed by eliminating every study one by one, and publication bias was judged by Egger's test and trim-and-fill method.

RESULTS

A total of 34 eligible studies involving 18,343 IPF patients were included in the meta-analysis. The pooled results by univariate Cox regression analysis showed that baseline BMI was a predictive factor for IPF mortality (HR = 0.93, 95%CI = [0.91, 0.94]). Furthermore, the results by the multivariable regression model indicated that baseline BMI was an independent risk factor for predicting IPF mortality (HR = 0.94, 95%CI = [0.91, 0.98]). Weight loss was identified as a risk factor for IPF mortality (HR = 2.74, 95% CI = [2.12, 3.54]; OR = 4.51, 95% CI = [1.72, 11.82]) and there was no predictive value of BMI for acute exacerbation (HR = 1.00, 95% CI= [0.93, 1.07]) or hospitalization (HR = 0.95, 95% CI = [0.89, 1.02]).

CONCLUSION

Low baseline BMI and weight loss in the course of IPF may indicate a high risk of mortality in patients with IPF, so it is meaningful to monitor and manage the nutritional status of IPF patients, and early intervention should be conducted for low BMI and weight loss.

Characteristics of Skeletal Muscle Strength in Subjects With Interstitial Lung Disease

OBJECTIVES

To investigate muscle strength and the prevalence of muscle weakness in adults with interstitial lung diseases (ILDs) compared to healthy subjects.

DESIGN

Cross-sectional (description of clinical features).

SETTING

Public referral center (University Hospital).

PARTICIPANTS

One hundred and twelve adults with ILD (n=48, 60±10yr, 68% female) and healthy counterparts (control group, n=64, 57±10yr, 58% female) (N=112).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURE(S)

Muscle strength and prevalence of muscle weakness in adults with ILD. Muscle strength was assessed via maximal isometric voluntary contraction of dominant upper and lower limb muscle groups. Data from the control group were used to generate reference equations. Muscle weakness was defined as a muscle strength value below the lower limit of normal calculated using data from the control group. Data were expressed as mean ± SD or median [interquartile range] according to the data distribution.

RESULTS

Compared to the control group, adults with ILD had lower muscle strength for all muscle groups assessed (values presented as %predicted: pectoralis major 75[57-86]%; quadriceps 72[58-87]%; latissimus dorsi 76[57-103]%; deltoid 74[64-98]%; biceps brachii 78[64-91]%; triceps brachii 84[62-101]%; P≤.001 for all). Prevalence of muscle weakness in people with ILD was 40% for pectoralis major, 25% for latissimus dorsi, 16% for triceps brachii, 20% for biceps brachii, 27% for deltoid and 46% for quadriceps.

CONCLUSIONS

Adults with ILD present a generalised reduction in peripheral Muscle strength, ranging between 20% to 46% of people depending on the muscle group assessed. and it was more prevalent in lower limb muscles.

Low Daily Step Count Associated with Small Erector Spinae Muscle Area and Sarcopenia in Idiopathic Pulmonary Fibrosis

Objective The daily step count is associated with mortality in idiopathic pulmonary fibrosis (IPF). However, the factors associated with this phenomenon are not yet fully understood. We therefore clarified its association with clinical parameters. Methods Fifty-nine patients with IPF with available data for daily step counts; 6-minute walk distance (6MWD); chest, abdominal, and pelvic computed tomography (CT); pulmonary function; psychological evaluations; and sarcopenia assessments were prospectively enrolled. The daily step count was measured continuously for seven consecutive days. The cross-sectional areas of the erector spinae muscles at the level of the 12th vertebra (ESMCSA) and psoas major muscle volume (PMV) obtained by CT were assessed. Results The average age of the patients was 73.3±8.1 years old, and the percent predicted forced vital capacity was 81.6%±15.8%. The median daily step count was 4,258 (2,155-6,991) steps. The average 6MWD, ESMCSA, and PMV were 413±97 m, 25.5±6.7 cm2, and 270±75.6 cm3, respectively. A linear regression analysis for daily step count showed that the ESMCSA and 6MWD were independent factors for the daily step count, whereas the PMV and skeletal muscle index were not. The daily step count, ESMCSA, and 6MWD were lower in patients with sarcopenia than in those without sarcopenia. Conclusion A lower daily step count was associated with a smaller erector spinae muscle area and sarcopenia in patients with IPF. Further studies are warranted to confirm the importance of physical therapy for muscle strengthening in patients with IPF.

Association between computed tomography-quantified respiratory muscles and chronic obstructive pulmonary disease: a retrospective study

BACKGROUND

This study examined the association between chest muscles and chronic obstructive pulmonary disease (COPD) and the relationship between chest muscle areas and acute exacerbations of COPD (AECOPD).

METHODS

There were 168 subjects in the non-COPD group and 101 patients in the COPD group. The respiratory and accessory respiratory muscle areas were obtained using 3D Slicer software to analysis the imaging of  computed tomography (CT). Univariate and multivariate Poisson regressions were used to analyze the number of AECOPD cases during the preceding year. The cutoff value was obtained using a receiver operating characteristic (ROC) curve.

RESULTS

We scanned 6342 subjects records, 269 of which were included in this study. We then measured the following muscle areas (non-COPD group vs. COPD group): pectoralis major (19.06 ± 5.36 cm2 vs. 13.25 ± 3.71 cm2, P < 0.001), pectoralis minor (6.81 ± 2.03 cm2 vs. 5.95 ± 1.81 cm2, P = 0.001), diaphragmatic dome (1.39 ± 0.97 cm2 vs. 0.85 ± 0.72 cm2, P = 0.011), musculus serratus anterior (28.03 ± 14.95 cm2 vs.16.76 ± 12.69 cm2, P < 0.001), intercostal muscle (12.36 ± 6.64 cm2 vs. 7.15 ± 5.6 cm2, P < 0.001), pectoralis subcutaneous fat (25.91 ± 13.23 cm2 vs. 18.79 ± 10.81 cm2, P < 0.001), paravertebral muscle (14.8 ± 4.35 cm2 vs. 13.33 ± 4.27 cm2, P = 0.007), and paravertebral subcutaneous fat (12.57 ± 5.09 cm2 vs. 10.14 ± 6.94 cm2, P = 0.001). The areas under the ROC curve for the pectoralis major, intercostal, and the musculus serratus anterior muscle areas were 81.56%, 73.28%, and 71.56%, respectively. Pectoralis major area was negatively associated with the number of AECOPD during the preceding year after adjustment (relative risk, 0.936; 95% confidence interval, 0.879-0.996; P = 0.037).

CONCLUSION

The pectoralis major muscle area was negative associated with COPD. Moreover, there was a negative correlation between the number of AECOPD during the preceding year and the pectoralis major area.

Association of musculoskeletal involvement with lung function and mortality in patients with idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease associated with high mortality. Low muscle mass, frailty and sarcopenia lead to functional impairment that negatively impact quality of life and survival but are not used in clinical practice. We aimed to determine the association of Fat-free mass index (FFMI) and frailty with lung function, exercise tolerance and survival in patients with IPF. In this study, 70 patients with IPF underwent assessment of body composition, lung function, 6-min walk distance (6MWD) testing, hand grip strength, quality of life (QoL) assessment by St. George's Respiratory questionnaire (SGRQ) and frailty assessment using the SHARE-FI tool. FFMI was calculated using pectoralis muscle cross-sectional area (PM-CSA) on CT chest images and the lowest quartile defined reduced muscle mass. Sarcopenia was defined as low FFMI and handgrip strength. Regression analyses were conducted to determine predictive value of frailty, low FFMI and sarcopenia on clinical outcomes. The Cox proportional hazards model was used to analyze the impact of FFMI and frailty score on survival. The mean age was 70 years with moderate impairment in lung function (mean ppFVC 68.5%, ppDLCO 45.6%). Baseline forced vital capacity (p < 0.001), diffusion capacity of lung for carbon monoxide (p =  < 0.01), 6WMD (p < 0.05) were significantly lower in frail patients compared to non-frail patients. BMI was found to closely correlate with FFMI (r = 0.79, p < 0.001), but not with frailty score (r = - 0.2, p = 0.07). Frailty was a significant predictor of FVC, DLCO, 6MWD, SGRQ scores when adjusted for age and gender. Muscle mass and sarcopenia were significant predictors of FVC, DLCO, but not 6MWD or QoL scores. Multivariate cox-proportional hazards ratio model adjusting for age and gender showed that frailty was significantly associated with increased mortality (HR = 2.6, 95% CI 1.1-6.1). Low FFMI (HR = 1.3, 95% CI 0.6-2.8), and sarcopenia (HR = 2.1, 95% CI 0.8-5.3), though associated with a trend to increased mortality, were not statistically significant. Frailty is associated with lower lung function and higher mortality in patients with IPF. Longitudinal evaluations are necessary to further determine the associations between low FFMI, sarcopenia and frailty with outcomes in IPF.

Neutrophil-lymphocyte ratio in patients with idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (iPPFE), a progressive fibrotic disease, is characterised by upper lobe-dominant lung fibrosis involving the pleura and subpleural lung parenchyma. However, no prognostic markers have been established for this condition. Associations between blood leucocyte levels and mortality have been reported in patients with idiopathic pulmonary fibrosis; therefore, we hypothesised that peripheral leucocyte levels are associated with mortality risk in patients with iPPFE.

METHODS

This retrospective study longitudinally assessed peripheral leucocyte counts at the time of diagnosis and 1 year after diagnosis in two cohorts of 127 patients with iPPFE (69 and 58 patients in Seirei and Hamamatsu cohorts, respectively).

RESULTS

A comprehensive assessment of peripheral leucocytes revealed that the neutrophil-lymphocyte ratio (NLR) was associated with mortality in patients with iPPFE after adjusting for age, sex and forced vital capacity in multivariate analyses (adjusted HR, 1.131; 95% CI, 1.032 to 1.227). When the patients were classified based on the median NLR, those with a high NLR had shorter survival than those with a low NLR (median, 32.2 vs 79.8 months; HR, 2.270; 95% CI, 1.416 to 3.696). Interestingly, the results of the NLR classification by median were longitudinally preserved in >70% of patients, and patients with consistently high NLR were at a higher risk of mortality than others (median, 24.8 vs 79.6 months; HR, 3.079; 95% CI, 1.878 to 5.031). Compared with the gender-age-physiology model, a composite model comprising age, sex and NLR could successfully stratify patients with iPPFE into three groups according to mortality risk.

CONCLUSION

The assessment of peripheral leucocyte counts is easy and might be useful in evaluating disease severity and mortality risk in patients with iPPFE. Our study suggests the importance of focusing on peripheral leucocyte levels in daily practice.

Rectus Femoris Cross-Sectional Area and Phase Angle asPredictors of 12-Month Mortality in Idiopathic Pulmonary Fibrosis Patients

BACKGROUND

The value of the phase angle (PhA), measured via bioelectrical impedance analysis (BIA), could be considered a good marker of the cell mass and the cell damage of a patient; however, there are new techniques, such as muscle ultrasonography, that allow the quantity and quality of muscle to be assessed in a minimally invasive way. The aim of this study is to determine the prognostic value of morphofunctional techniques in the prognosis of mortality in patients with idiopathic pulmonary fibrosis (IPF).

METHODS

This multicenter, cross-sectional study included 86 patients with idiopathic pulmonary fibrosis with a mean age of 71 years, 82.7% of whom were male. The nutritional risk of the patients was assessed by means of questionnaires, such as the Subjective Global Assessment (SGA), and non-invasive functional techniques, including BIA, nutritional ultrasound, and hand grip strength (HGS). Statistical analysis of the sample was performed using JAMOVI version 2.3.22.

RESULTS

Correlations were made between the RF-CSA techniques with PhA (r = 0.48, p < 0.001), BCM (r = 0.70, p < 0.001), SMI (r = 0.64, p < 0.001), and HGS (r = 0.54, p < 0.001). The cut-off points for 12-month mortality were PhA = 4.5° (AUC = 0.722, sensitivity of 72.7% and specificity of 66.6%), BCM = 28.8 kg (AUC = 0.609, sensitivity of 32.4% and specificity of 100.0%), RF-CSA = 3.00 cm2 (AUC = 0.857, sensitivity of 64.4% and specificity of 100.0%), 6MMW = 420 m (AUC = 0.830, sensitivity of 63.27% and specificity of 100.0%), and TUG = 7.2 s (AUC = 0.771, sensitivity of 100.0% and specificity of 56.67%). In addition, a multivariate analysis was performed with RF-CSA, HR = 8.11 (1.39-47.16, p = 0.020), and PhA of 6.35 (1.29-31.15, p = 0.023), taking into account age, sex, and BMI to determine mortality. Finally, a Kaplan-Meier survival analysis was conducted with low or normal values for classical parameters (GAP and T6MM) and new parameters (PhA, BCM, RF-CSA, and TUG).

CONCLUSION

RF-CSA and PhA were shown to be good prognostic markers of 12-month mortality and could, therefore, be useful screening tools to complement the nutritional assessment of IPF patients.

Prognostic impact of the cross-sectional area of the erector spinae muscle in patients with pleuroparenchymal fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE) progresses slowly but sometimes relatively quickly, leading to decreased activities of daily living (ADL) and muscle weakness. Skeletal muscle atrophy and muscle weakness in chronic obstructive pulmonary disease (COPD) patients may be caused by cachexia and are associated with reduced ADLs and increased risk of death. However, the association between skeletal muscle mass and the prognosis of PPFE patients remains unknown. We retrospectively analysed the clinical significance of the cross-sectional area of the erector spinae muscle (ESMCSA), a skeletal muscle index, and predictors of mortality within 3 years in PPFE 51 patients, idiopathic pulmonary fibrosis (IPF) 52 patients and COPD 62 patients. PPFE patients had significantly lower ESMCSA than IPF or COPD patients, and lower ESMCSA (< 22.57 cm2) was associated with prognosis within 3 years (log-rank test; p = 0.006), whereas lower body mass index (BMI) showed no association. Multivariate analysis showed that ESMCSA was an independent predictor of mortality within 3 years in PPFE patients (hazard ratio, 0.854; 95% confidence interval: 0.737-0.990, p = 0.036). These results suggest the importance of monitoring ESMCSA in PPFE patients and that assessing ESMCSA in PPFE patients could be a more useful prognostic indicator than BMI.

Linking Adiposity to Interstitial Lung Disease: The Role of the Dysfunctional Adipocyte and Inflammation

Adipose tissue has functions beyond its principal functions in energy storage, including endocrine and immune functions. When faced with a surplus of energy, the functions of adipose tissue expand by mechanisms that can be both adaptive and detrimental. These detrimental adipose tissue functions can alter normal hormonal signaling and promote local and systemic inflammation with wide-ranging consequences. Although the mechanisms by which adipose tissue triggers metabolic dysfunction and local inflammation have been well described, little is known about the relationship between adiposity and the pathogenesis of chronic lung conditions, such as interstitial lung disease (ILD). In this review, we detail the conditions and mechanisms by which adipose tissue becomes dysfunctional and relate this dysfunction to inflammatory changes observed in various forms of ILD. Finally, we review the existing basic and clinical science literature linking adiposity to ILD, highlighting the need for additional research on the mechanisms of adipocyte-mediated inflammation in ILD and its clinical implications.

The interplay of physical and cognitive function in rehabilitation of interstitial lung disease patients: a narrative review

Background and Objective

Interstitial lung disease (ILD) encompasses several diverse pulmonary pathologies that result in abnormal diffuse parenchymal changes. When prescribing rehabilitation, several additional factors need to be considered as a result of aging, polypharmacy, and comorbidities manifested in ILD patients. This review aims to discuss issues related to frailty, skeletal muscle and cognitive function that limit physical activities in ILD patients. It will also highlight exercise training and propose complementary strategies for pulmonary rehabilitation.

Methods

A literature search was performed in MEDLINE, CINAHL (inception to October 19th, 2022) using search terms based on concepts of: idiopathic pulmonary fibrosis or interstitial lung disease; frailty; muscular atrophy; skeletal muscle dysfunction; cognitive dysfunction; sleep quality; sleep disorders; anxiety disorders; or depressive disorders. After eligible texts were screened, additional references were included from references cited in the screened articles.

Key Content and Findings

Frailty and skeletal muscle dysfunction are common in ILD. Weight loss, exhaustion, and anti-fibrotic medications can impact frailty, whereas physical inactivity, aging, corticosteroids and hypoxemia can contribute to sarcopenia (loss of muscle mass and function). Frailty is associated with worse clinical status, exercise intolerance, skeletal muscle dysfunction, and decreased quality of life in ILD. Sarcopenia appears to influence wellbeing and can potentially affect overall physical conditioning, cognitive function and the progression of ILD. Optimal assessment tools and effective strategies to prevent and counter frailty and sarcopenia need to be determined in ILD patients. Even though cognitive impairment is evident in ILD, its prevalence and underlying neurobiological model of contributing factors (i.e., inflammation, disease severity, cardiopulmonary status) requires further investigation. How ILD affects cognitive interference, motor control and consequently physical daily activities is not well defined. Strategies such as pulmonary rehabilitation, which primarily focuses on strength and aerobic conditioning have demonstrated improvements in ILD patient outcomes. Future incorporation of interval training and the integration of motor learning could improve transfer of rehabilitation strategies to daily activities.

Conclusions

Numerous underlying etiologies of ILD contribute to frailty, skeletal muscle and cognitive function, but their respective neurobiologic mechanisms require further investigation. Exercise training increases physical measures, but complementary approaches may improve their applicability to improve daily activities.

Urinary titin N-fragment as a predictor of decreased skeletal muscle mass in patients with interstitial lung diseases

This study aimed to examine the validity of urinary N-terminal titin fragment/creatinine (urinary N-titin/Cr) reflecting muscle damage biomarker in patients with interstitial lung disease. This retrospective study enrolled patients with interstitial lung disease. We measured urinary N-titin/Cr. Furthermore, we measured the cross-sectional areas of the pectoralis muscles above the aortic arch (PMCSA) and erector spinae muscles of the 12th thoracic vertebra muscles (ESMCSA) to assess muscle mass until 1 year. We examined the correlation between urinary N-titin/Cr and the change in muscle mass. We plotted receiver operating characteristic curves to estimate the cut-off points for urinary N-titin/Cr for distinguishing the greater-than-median and smaller-than-median reduction of muscle mass after 1 year. We enrolled 68 patients with interstitial lung disease. The median urinary N-titin/Cr value was 7.0 pmol/mg/dL. We observed significant negative correlations between urinary N-titin/Cr and changes in the PMCSA after 1 year (p < 0.001) and changes in the ESMCSA after 6 months (p < 0.001) and 1 year (p < 0.001). The cut-off points for urinary N-titin/Cr were 5.2 pmol/mg/dL and 10.4 pmol/mg/dL in the PMCSA and ESMCSA, respectively. In summary, urinary N-titin/Cr may predict muscle loss in the long-term and act as a clinically useful biomarker reflecting muscle damage.

Geriatric Nutritional Risk Index is a predictor of tolerability of antifibrotic therapy and mortality risk in patients with idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive lung fibrosis of unknown aetiology. Epidemiological studies have suggested that IPF progression may negatively affect nutritional status. Weight loss during antifibrotic therapy is also frequently encountered. The association of nutritional status and outcome has not been fully evaluated in IPF patients.

METHODS

This retrospective multicohort study assessed nutritional status of 301 IPF patients receiving antifibrotic therapy (Hamamatsu cohort, n = 151; Seirei cohort, n = 150). Nutritional status was evaluated using the Geriatric Nutritional Risk Index (GNRI). The GNRI was calculated based on body mass index and serum albumin. The relationship between nutritional status and tolerability of antifibrotic therapy as well as mortality was explored.

RESULTS

Of 301 patients, 113 (37.5%) had malnutrition-related risk (GNRI < 98). Patients with malnutrition-related risk were older, had increased exacerbations and worse pulmonary function than those without a GNRI status <98. Malnutrition-related risk was associated with a higher incidence of discontinuation of antifibrotic therapy, particulary due to gastrointestinal disturbances. IPF patients with malnutrition-related risk (GNRI < 98) had shorter survival than those without such risk (median survival: 25.9 vs. 41.1 months, p < 0.001). In multivariate analysis, malnutrition-related risk was a prognostic indicator of antifibrotic therapy discontinuation and mortality, independent of age, sex, forced vital capacity, or gender-age-physiology index.

CONCLUSION

Nutritional status has significant effects on the treatment and outcome in patients with IPF. Assessment of nutritional status may provide important information for managing patients with IPF.

Skeletal muscle atrophy and short-term mortality in patients with acute exacerbation of idiopathic pulmonary fibrosis: an observational cohort study

BACKGROUND

Skeletal muscle atrophy, a common complication of idiopathic pulmonary fibrosis (IPF), and its presence upon diagnosis can indicate a poor prognosis. Patients with IPF frequently experience acute exacerbations (AE), which is associated with a high mortality rate. However, the association between skeletal muscle atrophy and short-term mortality remains unknown.

METHODS

We performed a retrospective, multicenter cohort study of patients admitted for AE-IPF in Japan. The cross-sectional areas of the erector spinae muscle (ESM_CSA) and the pectoralis muscle (PM_CSA) were analyzed via single-slice computed tomography (CT). The primary outcome was 90-day mortality. Survival probability was estimated using the Kaplan-Meier method, and the log-rank test was used between the low and high groups of ESM_CSA and PM_CSA. We used multivariable Cox proportional-hazards models to evaluate the association between ESM_CSA and PM_CSA and prognosis.

RESULTS

Of the 212 patients included, 94 (44%) died during the observation period. The low ESM_CSA group (<25.6 cm²) had a significantly worse prognosis than that of the high ESM_CSA group (≥25.6 cm²) (hazard ratio (HR) [95% confidence interval (CI)]: 1.52 [1.00-2.33], P = 0.049). Multivariable analyses showed that all-cause mortality was associated with low ESM_CSA (model 1, adjusted HR [95% CI]: 1.59 [0.98-2.60]; model 2, 1.55 [0.95-2.56], and model 3, 1.67 [1.00-2.78], respectively). The adjusted HR of low PM_CSA (<20.4 cm²) vs. high PM_CSA (≥20.4 cm²) was 1.39 (95% CI: 0.88-2.20).

CONCLUSIONS

Low ESM_CSA on CT images is associated with a high 90-day mortality rate in patients with AE-IPF.

Partial pressure of carbon dioxide levels reflect disease severity in idiopathic pleuroparenchymal fibroelastosis

BACKGROUND

Hypercapnia can cause a disturbance of consciousness and adversely affect a patient's general condition. Patients with interstitial lung disease seldom experience hypercapnia. Hypercapnia is a typical phenomenon in patients with pleuroparenchymal fibroelastosis (PPFE), especially in advanced stages. However, the clinical significance of hypercapnia in patients with idiopathic PPFE (iPPFE) has not been studied in detail.

METHODS

We retrospectively selected patients with iPPFE who had undergone blood gas analysis. The first blood gas data obtained after iPPFE diagnosis were examined. The partial pressure of carbon dioxide (PCO₂) levels and their association with characteristic iPPFE parameters, including the flat chest index (the ratio of the anteroposterior diameter of the thoracic cage to the transverse diameter of the thoracic cage), were investigated.

RESULTS

A total of 47 patients with iPPFE were included in this study. The PCO₂ level was moderately and inversely correlated with the forced vital capacity. (r = -0.431, P = 0.014), flat chest index (r = -0.497, P < 0.001), and body mass index (r = -0.313, P = 0.038) and was positively correlated with residual volume/total lung capacity. (r = 0.514, P < 0.01). A higher PCO₂ level was also significantly associated with poorer prognosis in patients with iPPFE.

CONCLUSIONS

PCO₂ levels could be used as an indicator of disease severity in patients with iPPFE.

Clinical features of idiopathic pleuroparenchymal fibroelastosis with progressive phenotype showing a decline in forced vital capacity

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is heterogeneous, with some patients showing a progressive decline in forced vital capacity (FVC). However, the clinical features of these cases with progressive phenotypes remain unknown.

METHODS

This retrospective study included 48 patients diagnosed with IPPFE who underwent longitudinal pulmonary function tests at our institution from 2005 to 2021. The progressive phenotype was defined as a relative decline of ≥10% in %FVC within two years from diagnosis of IPPFE, and its clinical features were evaluated.

RESULTS

Of the 48 patients, 23 (47.9%) were classified as progressive IPPFE. They were significantly older with a higher rate of dyspnea, fine crackles on chest auscultation, lower-lobe usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography, and lower %FVC at diagnosis than non-progressive IPPFE. Additionally, progressive IPPFE had a significantly higher rate of long-term oxygen therapy requirement, the incidence of pneumothorax, and weight loss after diagnosis, which showed worse survival than non-progressive IPPFE. The relative decline in %FVC and weight loss showed a significant positive correlation. Multivariate analysis revealed that lower body mass index tended to predict early progression, and the coexistence of lower-lobe UIP pattern was significantly associated with early progression. A decline in %FVC was an independent poor prognostic factor in IPPFE.

CONCLUSIONS

With a progressive decline in %FVC, IPPFE often has an advanced stage at diagnosis and lower-lobe UIP pattern and is associated with weight loss and worse survival.

The landscape of cancer cachexia in advanced non-small cell lung cancer: a narrative review

Background and Objective

Cancer cachexia presents with weight loss, anorexia, and fatigue and worsens the prognosis and quality of life of cancer patients. We aimed to summarize the current relevant discourse in the literature about cancer cachexia in the setting of non-small cell lung carcinoma and the possible current and future treatments.

Methods

We conduct a narrative review of the literature on the landscape of cancer cachexia in the context of non-small cell lung cancer, multimodality therapy, markers, imaging, tumor biology, pathology, chemoprevention, and technical advances.

Key Content and Findings

The need for appropriate intervention for cancer cachexia is increasing as the prognosis of patients with advanced non-small cell lung cancer is improving with advances in treatment. Tumor cells play a role in the pathogenesis of cachexia, where they release factors that elicit the production of inflammatory cytokines by the immune system resulting in decreased appetite, abnormal energy metabolism, and skeletal muscle degeneration. Comorbid chronic lung diseases are associated with pulmonary cachexia and sarcopenia and commonly occur in the context of lung cancer, further contributing to the increased incidence of cachexia in patients with lung cancer. Currently, a ghrelin-like agonist, anamorelin, is approved for the treatment of cancer cachexia and is used in clinical practice in Japan. The role that nutritional and exercise therapies can play as added treatments must be further explored.

Conclusions

Cancer cachexia remains a poorly understood phenomenon, and awareness must be raised through educational activities for health care providers and patient family members. In addition, new therapeutics targeting cancer cachexia, such as GDF-15 antibodies, are in development, and further progress is expected.

Phase angle in assessment and monitoring treatment of individuals with respiratory disease

Phase angle (PhA) represents a raw variable measured with bioelectrical impedance analysis (BIA) that is used to assess malnutrition in many diseases, including respiratory diseases, mainly chronic obstructive pulmonary disease (COPD). COPD patients with reduced PhA are older, more hypoxic and hypercapnic; patients with more severe COPD have reduced cell mass, evident skeletal muscle depletion, and worsening gas exchange. Malnourished patients with stable COPD in long-term oxygen therapy (LTOT) have more intense dyspnea at rest, greater weight loss over the past 12 months, and more exacerbations per year. Multiple regression analysis highlighted the significance of PhA° in the estimation of muscle strength: hand grip strength (HGS) and in that of respiratory muscles: maximal inspiratory pressure / max. expiratory pressure ratio (MIP/MEP). Furthermore, the relationship between PhA° and all-cause mortality in COPD patients was confirmed with the Cox regression model, Kaplan-Meier test, and log-rank tests. The role of malnutrition in idiopathic pulmonary fibrosis (IPF) is confirmed by the PhA° measurements which, regardless of body weight, is associated with the reduction in muscle mass of these patients, reduces their strength and exercise capacity, and greatly influences the prognosis. In conclusion PhA is a novel biomarker of morbidity and mortality in patients with severe respiratory diseases.

A Systematic Review of the Prognostic Significance of the Body Mass Index in Idiopathic Pulmonary Fibrosis

The identification of novel prognostic biomarkers might enhance individualized management strategies in patients with idiopathic pulmonary fibrosis (IPF). Although several patient characteristics are currently used to predict outcomes, the prognostic significance of the body mass index (BMI), a surrogate measure of excess fat mass, has not been specifically investigated until recently. We systematically searched PubMed, Web of Science, and Scopus, from inception to July 2022, for studies investigating associations between the BMI and clinical endpoints in IPF. The Joanna Briggs Institute Critical Appraisal Checklist was used to assess the risk of bias. The PRISMA 2020 statement on the reporting of systematic reviews was followed. Thirty-six studies were identified (9958 IPF patients, low risk of bias in 20), of which 26 were published over the last five years. Significant associations between lower BMI values and adverse outcomes were reported in 10 out of 21 studies on mortality, four out of six studies on disease progression or hospitalization, and two out of three studies on nintedanib tolerability. In contrast, 10 out of 11 studies did not report any significant association between the BMI and disease exacerbation. Our systematic review suggests that the BMI might be useful to predict mortality, disease progression, hospitalization, and treatment-related toxicity in IPF (PROSPERO registration number: CRD42022353363).

Impact of the amount of preoperative erector spinae muscle in stage I non-small-cell lung cancer

OBJECTIVES

Erector spinae muscle (ESM) is an antigravity muscle group that can be evaluated as an index of muscle loss on chest computed tomography. The amount of ESM has been reported to be related to the prognosis of several respiratory diseases. However, few studies clarify the impact on postoperative non-small-cell lung cancer (NSCLC). We investigated the relationship between ESM and postoperative prognosis in patients with early-stage NSCLC.

METHODS

We reviewed the medical records of 534 patients with stage I NSCLC who underwent lobectomy or segmentectomy. The ESM was identified by preoperative computed tomography, and the amount was normalized according to height and sex. Overall survival, lung cancer-related deaths and non-lung cancer-related deaths (NLCRD) were analysed using log-rank and Gray's tests. Multivariable analyses were conducted to identify factors that influenced overall survival (OS) and NLCRD.

RESULTS

The amount of ESM normalized according to height and sex was significantly associated with age and body mass index. When the amount was low, OS (5-year OS, 79.6 vs 89.5%; P< 0.001) and NLCRD (5-year cumulative mortality rate, 14.7 vs 6.8%; P< 0.001) were significantly worse, although no difference was found in lung cancer-related deaths.

CONCLUSIONS

The amount of preoperative ESM was strongly related to non-lung cancer-related death and was a significant prognostic factor for stage I NSCLC. Patients with a low amount of the muscle should be treated based on proper risk assessment.

Idiopathic pleuroparenchymal fibroelastosis: three-dimensional computed tomography assessment of upper-lobe lung volume

BACKGROUND

Idiopathic pleuroparenchymal fibroelastosis (iPPFE) is a rare interstitial lung disease characterised by predominant upper-lobe fibrosis involving the pleura and subpleural lung parenchyma. Despite its poor prognosis, there is no consensus on prognostic determinants of iPPFE to date. Because volume loss in the upper lobe is a distinct feature of iPPFE, we hypothesised that the lung volume of the bilateral upper lobes (upper-lobe volume) accurately indicates disease severity and mortality risk in iPPFE patients.

METHODS

This retrospective study assessed two cohorts of 132 patients with iPPFE (69 in Hamamatsu cohort; 63 in Seirei cohort) and 45 controls. Each lobe volume was quantitatively measured using three-dimensional computed tomography at the time of iPPFE diagnosis and standardised using predicted forced vital capacity.

RESULTS

The standardised upper-lobe volume in iPPFE patients was less than half that of controls, whereas the lower-lobe volume did not decrease. iPPFE patients with lower standardised upper-lobe volume had significantly shorter survival rates than those with higher volume (median survival: 6.08 versus 2.48 years, p<0.001). In multivariate analysis, the lower standardised upper-lobe volume was significantly associated with increased mortality adjusting for age, sex and forced vital capacity (HR 0.939). A composite scoring model, including age, sex and standardised upper-lobe volume, better predicted risk of death than the gender-age-physiology model.

CONCLUSION

Assessment of upper-lobe volume provides useful information for managing iPPFE by evaluating disease severity and mortality risk in clinical practice.

Prognostic significance of radiological pleuroparenchymal fibroelastosis inMycobacterium aviumcomplex lung disease: a multicentre retrospective cohort study

Background

Mycobacterium aviumcomplex (MAC) causes chronic respiratory infectious diseases with diverse clinical features and prognoses. Pleuroparenchymal fibroelastosis (PPFE) is a rare disease characterised by pleural fibrosis with subjacent intra-alveolar fibrosis and alveolar septal elastosis, with unique chest high-resolution CT (HRCT) features (radiological PPFE). An association between recurrent respiratory infections and PPFE formation has been hypothesised; however, the clinical significance of PPFE in MAC lung disease remains unclear.

Methods

This retrospective, multicentre study investigated the prevalence of radiological PPFE in patients with MAC lung disease and its association with clinical features and outcomes. Radiological PPFE was diagnosed on the basis of HRCT findings. Prognostic factors were identified using Cox proportional hazards and Fine-Gray models.

Results

Of 850 consecutive patients with definite MAC lung disease, 101 (11.9%) exhibited radiological PPFE. Patients with radiological PPFE had unique characteristics, such as lower body mass index, lower survival rate (5-year cumulative survival rate, 63.1% vs 91.7%; p<0.001) and a higher incidence of respiratory-related death (5-year cumulative incidence, 31.1% vs 3.6%; p<0.001), than those without radiological PPFE. In the multivariable analysis, the presence of radiological PPFE was independently associated with all-cause mortality (adjusted HR, 4.78; 95% CI, 2.87 to 7.95; p<0.001) and respiratory-related death (adjusted HR, 3.88; 95% CI, 2.14 to 7.01; p<0.001).

Interpretation

This large-scale study demonstrated that in patients with MAC lung disease, radiological PPFE was common, a phenotype associated with unique clinical features and poor prognosis, particularly respiratory-related death. The specific management of this subgroup should be established.

Computed tomography-based body composition measures in COPD and their association with clinical outcomes: A systematic review

Background

Computed tomography (CT) is commonly utilized in chronic obstructive pulmonary disease (COPD) for lung cancer screening and emphysema characterization. Computed tomography-morphometric analysis of body composition (muscle mass and adiposity) has gained increased recognition as a marker of disease severity and prognosis. This systematic review aimed to describe the CT-methodology used to assess body composition and identify the association of body composition measures and disease severity, health-related quality of life (HRQL), cardiometabolic risk factors, respiratory exacerbations, and survival in patients with COPD.

Methods

Six databases were searched (inception-September 2021) for studies evaluating adult COPD patients using thoracic or abdominal CT-muscle or adiposity body composition measures. The systematic review was conducted in accordance with the PRISMA guidelines.

Results

Twenty eight articles were included with 15,431 COPD patients, across all GOLD stages with 77% males, age range (mean/median 59–78 years), and BMI range 19.8–29.3 kg/m². There was heterogeneity in assessment of muscle mass and adiposity using thoracic (n = 22) and abdominal (n = 8) CT-scans, capturing different muscle groups, anatomic locations, and adiposity compartments (visceral, subcutaneous, and epicardial). Low muscle mass and increased adiposity were associated with increased COPD severity measures (lung function, exercise capacity, dyspnea) and lower HRQL, but were not consistent across studies. Increased visceral adiposity (n = 6) was associated with cardiovascular disease or risk factors (hypertension, hyperlipidemia, and diabetes). Low muscle CSA was prognostic of respiratory exacerbations or mortality in three of six studies, whereas the relationship with increased intermuscular adiposity and greater mortality was only observed in one of three studies.

Conclusion

There was significant variability in CT-body composition measures. In several studies, low muscle mass was associated with increased disease severity and lower HRQL, whereas adiposity with cardiovascular disease/risk factors. Given the heterogeneity in body composition measures and clinical outcomes, the prognostic utility of CT-body composition in COPD requires further study.

Pleuroparenchymal fibroelastosis in rheumatoid arthritis-associated interstitial lung disease

Background

Pleuroparenchymal fibroelastosis (PPFE) is a rare interstitial lung disease (ILD) featuring dense fibrosis of the visceral pleura and subpleural parenchyma, mostly in the upper lobes. PPFE can present in other ILDs, including rheumatoid arthritis-associated ILD (RA-ILD). The aim of this retrospective study was to investigate the prevalence and clinical implications of coexistent PPFE in RA-ILD.

Methods

Overall, 477 patients with RA-ILD were recruited from two cohorts; their clinical data and HRCT images were analysed. The criteria for diagnosing PPFE were (1) pleural thickening with bilateral subpleural dense fibrosis in the upper lobes, (2) evidence of disease progression, and (3) absence of other identifiable aetiologies.

Results

The median follow-up duration was 3.3 years. The mean age of the patients was 63.4 years, and 60.0% were women. PPFE was identified in 31 patients (6.5%). The PPFE group showed significantly lower body mass index and forced vital capacity (FVC) and more frequent usual interstitial pneumonia (UIP)-like pattern on HRCT than no-PPFE group. The risk factors for all-cause mortality were older age, lower FVC, and the presence of UIP-like pattern on HRCT; PPFE was not significantly associated with mortality in both all patients and a subgroup with a UIP-like pattern. The presence of PPFE was associated with a significantly increased risk of pneumothorax and greater decline in diffusing capacity.

Conclusions

PPFE was not rare in patients with RA-ILD and was significantly associated with an increased risk of pneumothorax and greater lung function decline, though we found no significant association with mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02064-z.

Standardised 3D-CT lung volumes for patients with idiopathic pulmonary fibrosis

Background

The assessment of lung physiology via pulmonary function tests (PFTs) is essential for patients with idiopathic pulmonary fibrosis (IPF). However, PFTs require active participation, which can be challenging for patients with severe respiratory failure, such as during moments of acute exacerbation (AE) of IPF. Recent advances have enabled the re-construction of 3-dimensional computed-tomography (3D-CT) images. This study established a standardisation method and quantitative analysis of lung volume (LV) based on anthropometry using 3D-CT images.

Methods

This is a retrospective multi-center cohort study. The standardised 3D-CT LV in patients with IPF at diagnosis (n = 140) and during AE (cohort1; n = 61 and cohort2; n = 50) and those of controls (n = 53) were assessed.

Results

The standardised 3D-CT LVs at IPF diagnosis were less than those of control patients, especially in the lower lung lobes. The standardised 3D-CT LVs were correlated with forced vital capacity (FVC) and validated using the modified Gender-Age-Physiology (GAP) index. The standardised 3D-CT LVs at IPF diagnosis were independently associated with prognosis. During AE, PFTs were difficult to perform, 3D-CT analyses revealed reduced lung capacity in both the upper and lower lobes compared to those obtained at diagnosis. Lower standardised 3D-CT LVs during AE were independently associated with worse outcomes in the two independent cohorts. In particular, volume loss in the upper lobe at AE had prognostic values.

Conclusions

A novel image quantification method for assessing pulmonary physiology using standardised 3D-CT-derived LVs was developed. This method successfully predicts mortality in patients with IPF and AE of IPF, and may be a useful alternative when PFTs cannot be performed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02062-1.

Serum creatinine/cystatin C ratio is a surrogate marker for sarcopenia in patients with idiopathic pulmonary fibrosis

BACKGROUND

The serum creatinine/cystatin C (Cr/CysC) ratio has attracted attention as a marker for sarcopenia, but has not been studied in patients with idiopathic pulmonary fibrosis (IPF). This study aimed to confirm the utility of the serum Cr/CysC ratio in predicting sarcopenia and investigate its clinical relevance.

METHODS

This cross-sectional pilot study prospectively enrolled patients with stable IPF. IPF was diagnosed through multidisciplinary discussions according to the 2018 international guidelines, and sarcopenia was diagnosed according to the 2019 consensus report of the Asian Working Group for Sarcopenia. Patient-reported outcomes (PROs) were evaluated using the modified Medical Research Council (mMRC) dyspnea scale, chronic obstructive pulmonary disease assessment test (CAT), and King's Brief Interstitial Lung Disease (K-BILD) questionnaire. The associations between serum Cr/CysC ratio and the presence of sarcopenia and other clinical parameters, including PROs scores, were examined.

RESULTS

The study enrolled 49 Japanese patients with IPF with a mean age of 73.0 ± 7.7 years and a mean percentage of predicted forced vital capacity of 80.4 ± 15.5%. Sarcopenia was diagnosed in 18 patients (36.7%), and the serum Cr/CysC ratio was 0.86 [0.76-0.94] (median [interquartile range]). The receiver operating characteristic curve analyses for the detection of sarcopenia according to the serum Cr/CysC showed that the area under the curve, optimal cutoff value, specificity, and sensitivity were 0.85, 0.88, 0.65, and 0.94, respectively. Sarcopenia was identified in 13% of patients with a high serum Cr/CysC ratio (≥ 0.88) and 60% of patients with a low serum Cr/CysC ratio (< 0.88) (P < 0.001). Multiple linear regression analysis showed that the serum Cr/CysC ratio was an independent predictive marker of worse PROs evaluated using mMRC (P < 0.05), CAT (P < 0.05), and K-BILD (P < 0.05).

CONCLUSIONS

This study showed that the serum Cr/CysC ratio may be a surrogate marker of sarcopenia in patients with IPF. Furthermore, it is important to pay attention to the serum Cr/CysC ratio because a lower serum Cr/CysC ratio is associated with worse PROs. Further studies are required to validate these observations to determine whether the Cr/CysC ratio can be used to detect sarcopenia in patients with IPF.

Decreased peak expiratory flow rate associated with mortality in idiopathic pulmonary fibrosis: A preliminary report

Objectives

The peak expiratory flow rate (PEFR) is known to decrease in patients with sarcopenia. However, little is known about the clinical impact of the PEFR in idiopathic pulmonary fibrosis (IPF). This study aimed to confirm whether a decrease in PEFR over 6 months was associated with survival in IPF patients.

Methods

Consecutive IPF patients who had been assessed at a single center were retrospectively analyzed. The relative decline in PEFR over 6 months was assessed. Survival analyses were performed by univariate and multivariate Cox proportional hazard models.

Results

A total of 61 eligible cases (average age 70 years) were examined, and 21 patients (34.4%) died. The univariate Cox regression analysis showed that the body mass index, baseline % predicted forced vital capacity (FVC), baseline % predicted PEFR, % predicted diffusion capacity for carbon monoxide (DL_CO), relative decline in FVC, and relative decline in PEFR were prognostic factors. On multivariate analyses, relative decline in PEFR (hazard ratio [HR] 1.037, p < .05) and baseline % predicted FVC (HR 0.932, p < .001) were independent prognostic factors, whereas relative decline in FVC was not.

Conclusion

A decrease in PEFR after 6 months may predict worse survival in patients with IPF.

Frequency and impact on clinical outcomes of sarcopenia in patients with idiopathic pulmonary fibrosis

Objectives

Sarcopenia is a syndrome characterized by reduced muscle mass and function. It is well-recognized as a complication in chronic diseases such as chronic obstructive pulmonary disease. However, little is known about sarcopenia in patients with idiopathic pulmonary fibrosis (IPF). This study aimed to investigate the clinical characteristics of sarcopenia and the association between quality of life and sarcopenia in patients with IPF.

Methods

In this pilot cross-sectional study, 56 Japanese outpatients with IPF (49 men) were enrolled prospectively. Sarcopenia was diagnosed according to the criteria of the Asian Working Group for Sarcopenia 2019. Its associations with clinical parameters including age, pulmonary functions, physical performance, and patient-reported outcomes (PROs) were examined.

Results

The frequency of sarcopenia was 39.3% (n = 22) in this cohort. There were significant differences in St George’s Respiratory Questionnaire (p = .005), modified Medical Research Council score (p = .004), and Hospital and Anxiety Depression Scale depression score (p = .030) between the sarcopenic and non-sarcopenic groups. On multivariate regression analysis, 6-min walk distance (6MWD) was an independent factor associated with sarcopenia (odds ratio 1.241, 95% confidence interval 1.016–1.515, p = .034).

Conclusion

Sarcopenia was associated with PROs and physical performance in patients with IPF.

Impact of sarcopenia on chemotherapy-triggered exacerbation of interstitial lung disease in patients with non-small cell lung cancer

Background

While recent evidence has suggested that sarcopenia could predict chemotoxicity, its association with chemotherapy‐triggered interstitial lung disease (ILD) exacerbations has yet to be investigated. Thus, the present study sought to determine whether sarcopenia could predict ILD exacerbations and overall survival (OS) in patients with ILD‐complicated non‐small cell lung cancer (NSCLC).

Methods

From January 2010 to July 2020, 74 patients with ILD‐complicated NSCLC who received chemotherapy were retrospectively investigated. After categorizing patients according to the presence or absence of sarcopenia based on the psoas muscle index, ILD exacerbation rates and OS were evaluated.

Results

Among the patients in the study, 39 were included in the sarcopenia group. Moreover, 17 (22.9%) patients developed ILD exacerbations, with the sarcopenia and nonsarcopenia groups having an exacerbation rate of 33.3% and 11.4%, respectively (p = 0.025). Multivariate analysis identified sarcopenia as an independent predictor of ILD exacerbations (p = 0.039). Furthermore, patients with sarcopenia demonstrated a significantly shorter median OS compared to those without the same (9.2 vs. 13.3 months; p = 0.029).

Conclusions

Sarcopenia predicted chemotherapy‐triggered ILD exacerbation and OS in patients with ILD‐complicated NSCLC, suggesting its utility in determining treatment approaches.

Relationship between body composition, exercise capacity and health-related quality of life in idiopathic pulmonary fibrosis

INTRODUCTION

Bioelectrical impedance analysis (BIA) can be used to estimate Fat-Free Mass Index (FFMI). However, the use of directly measured BIA variables, such as phase angle (PhA), has gained attention. The frequency of low FFMI and PhA and its associations with exercise capacity and health-related quality of life (HRQL) in patients with idiopathic pulmonary fibrosis (IPF) have been scarcely studied.

OBJECTIVES

To investigate the frequency of low FFMI and PhA and their associations with exercise capacity and HRQL in patients with IPF.

METHODS

Patients underwent assessment of lung function, body composition, exercise capacity by the 6 min walk distance (6MWD), and HRQL by the Medical Outcomes Study Short-Form 36-item Questionnaire (SF-36). Patients were classified as presenting normal or low PhA or FFMI, accordingly to the 10th percentiles of age-sex-body mass index (BMI)-specific reference values.

RESULTS

98 patients (84 males, age: 68±8 years, forced vital capacity: 64%±18%predicted) were included. 24 patients presented low PhA. They were characterised by worse lung function, exercise capacity and HRQL compared with patients with normal PhA. 10 patients presented low FFMI, but despite differences in body composition, no differences were found between these patients and patients with normal FFMI. In a single regression analysis, age, lung function and body composition variables (except FFMI) were related to 6MWD and SF-36 Physical Summary Score (R²=0.06-0.36, p<0.05). None of the variables were related to SF-36 Mental Summary Score.

CONCLUSION

One-fourth of the patients with IPF with normal to obese BMI present abnormally low PhA. Patients classified as low PhA presented worse lung function, exercise capacity and HRQL.

Lung Features in Individuals with Biomass Smoke Exposure Characterized by CT Scan and Changes in Pulmonary Function

Background and Objective

To determine the effects of BSE (biomass smoke exposure) on pulmonary and non-pulmonary changes in patients with COPD compared with normal individuals.

Methods

Using a cohort, we recruited 16 healthy individuals with BSE (BSE normal), 19 patients with BSE+COPD, 13 healthy individuals with cigarette smoke exposure (CSE normal), 25 patients with CSE+COPD, and 25 healthy controls. Patients with GOLD stage I and II COPD were included. Baseline data (demographic data, BSE or CSE, lung function, and CT findings) and follow-up lung function data were collected. CT parameters of emphysema, pulmonary small vessels, airway remodeling, pectoralis muscles, and erector spinae muscle were measured.

Results

Individuals with BSE were mainly women (32/35, 91.43%). Compared with the CSE+COPD group, the BSE+COPD group demonstrated slower lung function decline, increased lower lung emphysema, narrower airway lumen dimensions and increased airway wall thickening in the moderate and small airways (all P<0.05). Compared with healthy controls, the CSE normal and BSE normal groups exhibited significant reductions in pulmonary small vessel area and obvious airway remodeling in small airways (P<0.05). Compared with the BSE normal group, the BSE+COPD group showed significantly more severe emphysema and airway remodeling, as well as reduced left pectoralis major muscle area (all P<0.05).

Conclusion

Healthy individuals with BSE had reduced pulmonary small vessel area and evidence of airway remodeling; patients with BSE and COPD showed more severe emphysema, airway remodeling, and reductions in pectoralis major muscle area.

Clinical Trial Registration

ChiCTR-OO-14004264.

Combined assessment of the GAP index and body mass index at antifibrotic therapy initiation for prognosis of idiopathic pulmonary fibrosis

Antifibrotic therapy (AFT) slows disease progression in patients with idiopathic pulmonary fibrosis (IPF). The Gender-Age-Physiology (GAP) index, was developed based on data at IPF diagnosis before the introduction of AFT and has not been evaluated in the AFT context. Further, recent advances have revealed the importance of body-composition factors in prognosis of IPF treated with AFT. This multi-centre, retrospective study aimed to evaluate the GAP index and body mass index (BMI) at the time of AFT initiation for predicting prognosis in patients with IPF. This study included two patient cohorts of IPF receiving AFT, Hamamatsu cohort (n = 110) and Seirei cohort (n = 119). The distribution of GAP stages I, II, and III was 38.2%, 43.6%, and 18.2%, respectively, in Hamamatsu cohort; in Seirei cohort, it was 41.2%, 50.4%, and 8.4%, respectively. In both cohorts, the GAP index distinctly classified prognosis into three groups (log-rank test). Interestingly, a lower BMI showed prognostic value independent of the GAP index in multivariate analyses. Subsequently, combining the GAP index with BMI at AFT initiation successfully divided the patients with IPF into four distinct prognoses. Assessment of the GAP index and BMI measurement at AFT initiation are important for predicting prognosis in patients with IPF.

Dynapenia is highly prevalent in older patients with advanced idiopathic pulmonary fibrosis

Body composition and muscle strength are emerging aspects in idiopathic pulmonary fibrosis (IPF) clinical assessment. We aimed to study the relationships of handgrip strength (HGS) with anthropometric variables, body composition, and disease staging, and to evaluate the prevalence of dynapenia in 102 clinically stable IPF patients (70 M; mean age: 69.4 years). Fat-free mass (FFM), skeletal muscle (SM) were estimated with bioimpedance analysis. HGS was measured with a digital handle dynamometer for both dominant and non-dominant body sides. Dynapenia was identified according to six recognized criteria sets. Mean body mass index (BMI) was 28.2 ± 4.7 kg/m², with a prevalence of overweight (BMI > 25 and < 30 kg/m²) and obesity (BMI ≥ 30 kg/m²) of 35% and 37%, respectively. FFM and SM were greater in males, whereas percentage body fat was higher in women. HGS was higher and declined with age slightly more rapidly in men, showing a stronger correlation with FFM and SM. Dynapenia prevalence ranged from 20.6 to 56.9%, depending on the criteria used, and was more frequent in older patients and advanced disease. Dynapenia is highly prevalent in IPF. HGS is a promising proxy marker of muscle function to be used in clinical evaluation and follow-up programs.

A proposed prognostic prediction score for pleuroparenchymal fibroelastosis

BACKGROUND

Clinical course of pleuroparenchymal fibroelastosis (PPFE) shows considerable variation among patients, but there is no established prognostic prediction model for PPFE.

METHODS

The prediction model was developed using retrospective data from two cohorts: our single-center cohort and a nationwide multicenter cohort involving 21 institutions. Cox regression analyses were used to identify prognostic factors. The total score was defined as the weighted sum of values for the selected variables. The performance of the prediction models was evaluated by Harrell's concordance index (C-index). We also examined the usefulness of the gender-age-physiology (GAP) model for predicting the prognosis of PPFE patients.

RESULTS

We examined 104 patients with PPFE (52 cases from each cohort). In a multivariate Cox analysis, a lower forced vital capacity (FVC [defined as FVC < 65%]; hazard ratio [HR], 2.23), a history of pneumothorax (HR, 3.27), the presence of a lower lobe interstitial lung disease (ILD) (HR, 2.31), and higher serum Krebs von den Lungen-6 (KL-6) levels (> 550 U/mL, HR, 2.56) were significantly associated with a poor prognosis. The total score was calculated as 1 × (FVC, < 65%) + 1 × (history of pneumothorax) + 1 × (presence of lower lobe ILD) + 1 × (KL-6, > 550 U/mL). PPFE patients were divided into three groups based on the prognostic score: stage I (0-1 points), stage II (2 points), and stage III (3-4 points). The survival rates were significantly different in each stage. The GAP stage was significantly associated with the prognosis of PPFE, but no difference was found between moderate (stage II) and severe (stage III) disease. Our new model for PPFE patients (PPFE Prognosis Score) showed better performance in the prediction of mortality in comparison to the GAP model (C-index of 0.713 vs. 0.649).

CONCLUSIONS

Our new model for PPFE patients could be useful for predicting their prognosis.

Pectoralis muscle area and its association with indices of disease severity in interstitial lung disease

RATIONALE

The pathophysiology of interstitial lung disease (ILD) impacts body composition, whereby ILD severity is linked to lower lean mass.

OBJECTIVES

To determine i) if pectoralis muscle area (PMA) is a surrogate for whole-body lean mass in ILD, ii) whether PMA is associated with ILD severity, and iii) if the longitudinal change in PMA is associated with pulmonary function and mortality in ILD.

METHODS

Patients with ILD (n = 164) were analyzed retrospectively. PMA was quantified from a chest computed tomography scan. Peripheral oxygen saturation (SpO₂), 6-min walk distance (6MWD), and pulmonary function were obtained as part of routine clinical care. Dyspnea and quality of life were assessed using the UCSD Shortness of Breath Questionnaire and European Quality of Life 5 Dimensions questionnaire, respectively.

RESULTS

PMA was associated with whole-body lean mass (p < 0.001). After adjusting for age, sex, height, body mass, and prednisone status, PMA was associated with %-predicted forced vital capacity (FVC), %-predicted diffusion capacity (DL_CO), resting and exertional SpO₂, and dyspnea (all p < 0.05), but not forced expiratory volume in 1 s (FEV₁), FEV₁/FVC, 6MWD, or quality of life (all p > 0.05). The annual negative PMA slope was associated with annual negative slopes in FVC, FEV₁, and DL_CO (all p < 0.05), but not FEV₁/FVC (p = 0.46). Annual slope in PMA was associated with all-cause mortality (hazard ratio = -0.80, 95% CI:0.889-0.959; p < 0.001).

CONCLUSION

In patients with ILD, PMA is a suitable surrogate for whole-body lean mass. A lower PMA is associated with indices of ILD severity, which supports the notion that ILD progression may involve sarcopenia.

Quantitative assessment of the association between erector spinae muscle and in-hospital mortality in elderly patients with pulmonary tuberculosis

Objective

Skeletal muscle size is considered a predictor of prognosis in patients with respiratory diseases including Mycobacterium avium complex lung disease. However, no research focused on its impact on prognosis in patients with pulmonary tuberculosis (TB). Thus, this study aimed to assess the association between erector spinae muscle (ESM) size and in-hospital mortality among patients with pulmonary TB.

Results

We retrospectively included 258 consecutive patients aged over 65 years old, who were admitted to the hospital for bacteriologically confirmed pulmonary TB, and all underwent chest computed tomography (CT) scan upon admission. The cross-sectional area of the ESM (ESMcsa) was measured at the lower margin of the 12th thoracic vertebra on a single-slice CT scan image and was adjusted according to body surface area (BSA). In total, 71 (28%) patients died during hospitalization. The non-survivor group had a high incidence of respiratory failure and comorbidities and lower hemoglobin and albumin levels, performance status score, and ESMcsa/BSA. Multivariate analysis revealed that low performance status score and hemoglobin and albumin levels, but not ESMcsa/BSA and body mass index, could independently predict in-hospital mortality after adjusting for age and comorbidities. Therefore, ESM size was not associated with in-hospital mortality in patients with pulmonary TB.

Prognostic and Clinical Value of Cluster Analysis in Idiopathic Pleuroparenchymal Fibroelastosis Phenotypes

Idiopathic pleuroparenchymal fibroelastosis (PPFE) is a distinctive interstitial pneumonia with upper lobe predominance that shows unique morphological features among idiopathic interstitial pneumonias (IIPs). Affected patients have a variety of clinical presentations with heterogeneous clinical courses. Cluster analysis is a valuable tool for identifying distinct clinical phenotypes under heterogeneous conditions. This study aimed to identify the phenotypes of patients with idiopathic PPFE. Using cluster analysis, novel PPFE phenotypes were identified among subjects from our multicenter cohort, and outcomes were stratified according to phenotypic clusters. Among the subjects with baseline data (N = 84), four clusters were identified. Cluster 1 included younger male subjects with coexisting non-UIP-like patterns. Cluster 2 included elderly female nonsmokers with low body mass index (BMI). Cluster 3 included elderly male smokers with a coexisting IP-like pattern. Cluster 4 included younger male smokers without lower lobe lesions. Patients in cluster 3 had significantly worse survival outcomes than those in clusters 1, 2, and 4 (p < 0.001, p = 0.0041, and p = 0.0155, respectively). Among idiopathic PPFE patients, cluster analysis using baseline characteristics identified four distinct clinical phenotypes that might predict survival outcomes.

Lung Transplantation for Pleuroparenchymal Fibroelastosis

Pleuroparenchymal fibroelastosis (PPFE), a new disease entity associated with interstitial pneumonia, is characterized by fibrosis and elastosis involving the pleura and subpleural lung parenchyma, predominantly in the upper lobe. As the awareness of this disease entity has increased, many studies have revealed the prevalence and incidence, clinical and pathological characteristics, and disease course of PPFE. Patients with PPFE reportedly have several unique clinical characteristics—including an extremely low body mass index with a slender body and chest wall deformity, known as “flat chest”. As this disease progresses, shrinking of the lungs often causes life-threatening complications, such as pneumothorax, and associated air leak syndrome. Lung transplantation is considered the only effective treatment for patients with advanced PPFE; however, little is known about the influences of the characteristics of PPFE on the outcome of lung transplantation. This review focuses on the unique clinicopathologic characteristics of PPFE and associated outcomes of lung transplantation for these patients.

Pleuroparenchymal fibroelastosis in Korean patients: clinico-radiologic-pathologic features and 2-year follow-up

BACKGROUND/AIMS

Pleuroparenchymal fibroelastosis (PPFE) is a type of rare idiopathic interstitial pneumonia that is characterized by predominantly upper lobe involvement with pleural fibrosis and subjacent parenchymal fibrosis. This study aimed to determine the clinico-radiologic-pathologic features and prognosis of Korean patients with PPFE.

METHODS

A total of 26 patients who were confirmed to have PPFE by lung biopsy, were included, and their clinico-radiologic-pathologic findings were retrospectively analyzed.

RESULTS

The mean follow-up period was 23.8 months, and the mean age of the patients was 62.5 years; 61.5% were men and 50% were smokers. Cough and dyspnea were the most frequent presenting symptoms, and restrictive pattern was the most common observation in lung function. In 84.6% of the subjects, lower lobe involvement was found on chest computed tomography, and the usual interstitial pneumonia (UIP) pattern was the most common (59.1%). Among patients whose lower lobe was biopsied (n = 13), the UIP pattern was the most common (46.2%). Patients with lower lobe involvement were older and walked a shorter distance during the 6-minute walk test, compared to those without. Spontaneous pneumothorax was a common complication (26.9%), and 15.4% of the patients died mostly due to pneumonia (100%). The 1- and 3-year survival rates were 90.2% and 84.5%, respectively.

CONCLUSION

Clinical features of Korean patients with PPFE were similar to those reported previously; however, lower lobe involvement was more frequent. During follow-up, one-fourth of the patients experienced pneumothorax and one-fifth died from pneumonia.

Quantitative assessment of erector spinae muscles and prognosis in elderly patients with pneumonia

Erector spinae muscle (ESM) size has been reported as a predictor of prognosis in patients with some respiratory diseases. This study aimed to assess the association of ESM size on all-cause in-hospital mortality among elderly patients with pneumonia. We retrospectively included patients (age: ≥ 65 years) admitted to hospital from January 2015 to December 2017 for community-acquired pneumonia who underwent chest computed tomography (CT) on admission. The cross-sectional area of the ESM (ESMcsa) was measured on a single-slice CT image at the end of the 12th thoracic vertebra and adjusted by body surface area (BSA). Cox proportional hazards regression models were used to assess the influence of ESMcsa/BSA on in-hospital mortality. Among 736 patients who were admitted for pneumonia, 702 patients (95%) underwent chest CT. Of those, 689 patients (98%) for whom height and weight were measured to calculate BSA were included in this study. Patients in the non-survivor group were significantly older, had a greater frequency of respiratory failure, loss of consciousness, lower body mass index, hemoglobin, albumin, and ESMcsa/BSA. Multivariate analysis showed that a lower ESMcsa/BSA independently predicted in-hospital mortality after adjusting for these variables. In elderly patients with pneumonia, quantification of ESMcsa/BSA may be associated with in-hospital mortality.

The pathogenesis and pathology of idiopathic pleuroparenchymal fibroelastosis

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare subtype of idiopathic interstitial pneumonias that consists of elastofibrosis involving the lung parenchyma and pleural collagenous fibrosis predominantly located in the upper lobes. IPPFE has various distinct clinical and physiological characteristics, including platythorax and a marked decrease of forced vital capacity with an increased residual volume on a respiratory function test. The concept of IPPFE is now widely recognized and some diagnostic criteria have been proposed. In addition, the accumulation of cases has revealed the pathological features of IPPFE. However, little is known about the pathogenesis or the process of disease formation in IPPFE. This review article will provide a summary of the pathological features and previously reported hypotheses on disease formation in IPPFE, to discuss the potential etiologies and pathogenesis of IPPFE.

Physiological Criteria Are Useful for the Diagnosis of Idiopathic Pleuroparenchymal Fibroelastosis

BACKGROUND

Diagnostic criteria of idiopathic pleuroparenchymal fibroelastosis (IPPFE) were recently proposed, including physiological criteria of the body mass index (BMI) and percentage of the predicted values of residual volume (RV)/total lung capacity (TLC) (RV/TLC %pred.). The aim of this study was to evaluate (i) whether the physiologic criteria are useful for the diagnosis and (ii) whether the flat chest index, defined as the ratio of the anteroposterior diameter to the transverse diameter of the thoracic cage, could be an alternative parameter to RV/TLC %pred.

METHODS

We selected consecutive IPPFE patients and idiopathic pulmonary fibrosis (IPF) patients. We examined the diagnostic sensitivity and specificity of the physiological criteria and flat chest index for differentiating IPPFE patients from IPF patients.

RESULTS

This study included 37 IPPFE patients and 89 IPF patients. The physiological criteria distinguished IPPFE patients from IPF patients with a sensitivity of 78.6% and specificity of 88.0%. The combination of the flat chest index and BMI was also effective for differentiation (sensitivity of 82.1% and specificity of 89.3%).

CONCLUSION

We verified the good performance of the physiologic criteria in a different cohort. When the RV/TLC is not measured, using the flat chest index instead of RV/TLC %pred. may be reasonable.

Extent of pulmonary fibrosis on high-resolution computed tomography is a prognostic factor in patients with pleuroparenchymal fibroelastosis

BACKGROUND

Several prognostic factors for pleuroparenchymal fibroelastosis (PPFE) have recently been reported. However, detailed high-resolution computed tomography (HRCT) findings have not yet been evaluated as prognostic factors. This study retrospectively investigated whether HRCT findings are prognostic factors in patients with PPFE compared to those with idiopathic pulmonary fibrosis (IPF).

METHODS

Patients with PPFE and IPF diagnosed at our hospital between January 2008 and December 2016 were enrolled. Clinical and HRCT characteristics were obtained. In addition to our patients, we also analyzed data of PPFE patients whose cause of death had been identified in previous studies.

RESULTS

We enrolled 15 patients with PPFE and 75 patients with IPF. Consolidation and maximum pleural thickening were significantly higher in patients with PPFE than in those with IPF (both P < .001). Fibrosis score, honeycomb area, and traction bronchiectasis were not significantly different between these patient groups but were significant prognostic factors in patients with PPFE in univariate analysis (P = .021, P = .017, and P = .014, respectively). The proportions of deaths by acute exacerbation or lung cancer were significantly lower in patients with PPFE than in those with IPF (P < .001 and P = .001, respectively), whereas death by respiratory failure was significantly more frequent in PPFE patients (P < .001).

CONCLUSIONS

HRCT findings, such as fibrosis score, honeycomb area, and traction bronchiectasis, were independent prognostic factors in patients with PPFE. Respiratory failure, but not acute exacerbation and lung cancer, was the main cause of death in patients with PPFE.

Pleuroparenchymal fibroelastosis in patients with idiopathic pulmonary fibrosis

BACKGROUND AND OBJECTIVE

PPFE is characterized by fibrosis in the pleura and subpleural lung parenchyma in the upper lobes, while other types of ILD, mainly UIP, can be observed in about half of the patients in their lower lobes. The aim of this study was to evaluate the clinical significance of the radiologically defined PPFE in patients with IPF.

METHODS

Clinical data and chest CT images were retrospectively analysed in 445 patients with IPF (biopsy-proven cases, n = 165). The radiological criteria of PPFE were defined as follows: (i) bilateral subpleural dense fibrosis with or without pleural thickening in the upper lobes, (ii) evidence of disease progression and (iii) no clinical evidence of identifiable aetiologies.

RESULTS

The median follow-up period was 43.0 months. The mean age of the patients was 66.4 years and 76.4% were male. PPFE was identified in 28 patients (6.3%). The PPFE group showed lower BMI and lung function (FVC and TLC) at baseline, more frequent pneumothorax and pneumomediastinum, higher decline rates in lung function and poorer prognosis during follow-up than the no-PPFE group. PPFE was an independent risk factor (HR = 2.953, 95% CI: 1.350-6.460, P = 0.007) for pneumothorax or pneumomediastinum, but not for mortality in patients with IPF.

CONCLUSION

Among patients with IPF, the PPFE group, when compared to the no-PPFE group, showed lower BMI and lung function and showed more frequent complications and poorer survival during follow-up.

Unilateral pleuroparenchymal fibroelastosis as a rare form of idiopathic interstitial pneumonia: A case report

BACKGROUND

Pleuroparenchymal fibroelastosis (PPFE) is a rare idiopathic interstitial pneumonia characterized by predominantly upper lobe involvement with pleural fibrosis and subjacent parenchymal fibrosis. Recently, there have been increasing reports of PPFE, and PPFE might coexist with other interstitial lung diseases in the lower lobe and upper lobe. However, cases of unilateral PPFE are scarce.

CASE SUMMARY

A 75-year-old Korean male presented to our hospital with chronic dry cough and exertional dyspnea. The patient’s symptoms started 6 mo previously and had been gradually worsening. At the time of presentation, he felt dyspnea when walking at his own pace. Radiologic findings suggested PPFE, but the lesion was localized in the upper lobe of the right lung. After multidisciplinary discussion, a transbronchial lung biopsy in the right upper lobe revealed collapsed alveoli with parenchymal fibroelastosis, and elastic van Gieson staining demonstrated septal elastosis with intra-alveolar collagenosis, which met the histopathologic criteria of definite PPFE. After multidisciplinary discussion in an experienced interstitial lung disease center, we confirmed the diagnosis of unilateral PPFE. Furthermore, we confirmed the progression of PPFE on radiologic findings during the follow-up period.

CONCLUSION

Clinicians should consider PPFE, even in cases with unilateral, predominantly upper lung involvement in interstitial lung disease patients through multidisciplinary discussion.

Cause of mortality and sarcopenia in patients with idiopathic pulmonary fibrosis receiving antifibrotic therapy

BACKGROUND AND OBJECTIVE

Recent research has highlighted the fundamental role of sarcopenia, characterized by loss of skeletal muscle mass and strength, with a risk of poor outcomes. AFT preserves lung function by preventing the annual decline in FVC and is associated with improved outcomes in patients with IPF. However, altered cause of death and prognostic implications of sarcopenia in patients with IPF receiving AFT remain unknown.

METHODS

This study comprised two cohorts of patients with IPF receiving AFT, historical cohort of IPF patients without AFT and controls. The cause of mortality was compared with a historical cohort. Sarcopenia was assessed by measuring the ESM_CSA and ESM_MA via CT.

RESULTS

Patients with IPF had smaller ESM_CSA and lower ESM_MA but similar BMI than controls, suggesting patients with IPF had skeletal muscle loss without any obvious body weight loss. The most common cause of mortality in patients receiving AFT was chronic respiratory failure, accounting for approximately 60%, and decreased proportions of LC were found. Subsequently, low ESM_CSA was an independent prognostic factor associated with worse survival rates. Furthermore, combined assessment of ESM_CSA , %FVC predicted and BMI values provided clear prognostic distinction.

CONCLUSION

Patients with IPF receiving AFT showed skeletal muscle loss without obvious weight loss. These patients mostly died by chronic respiratory failure, and skeletal muscle wasting has prognostic significance, suggesting that preventing sarcopenia as well as preserving lung function are important for managing these patients.

Target Analysis of Volatile Organic Compounds in Exhaled Breath for Lung Cancer Discrimination from Other Pulmonary Diseases and Healthy Persons

The aim of the present study was to investigate the ability of breath analysis to distinguish lung cancer (LC) patients from patients with other respiratory diseases and healthy people. The population sample consisted of 51 patients with confirmed LC, 38 patients with pathological computed tomography (CT) findings not diagnosed with LC, and 53 healthy controls. The concentrations of 19 volatile organic compounds (VOCs) were quantified in the exhaled breath of study participants by solid phase microextraction (SPME) of the VOCs and subsequent gas chromatography-mass spectrometry (GC-MS) analysis. Kruskal-Wallis and Mann-Whitney tests were used to identify significant differences between subgroups. Machine learning methods were used to determine the discriminant power of the method. Several compounds were found to differ significantly between LC patients and healthy controls. Strong associations were identified for 2-propanol, 1-propanol, toluene, ethylbenzene, and styrene (p-values < 0.001-0.006). These associations remained significant when ambient air concentrations were subtracted from breath concentrations. VOC levels were found to be affected by ambient air concentrations and a few by smoking status. The random forest machine learning algorithm achieved a correct classification of patients of 88.5% (area under the curve-AUC 0.94). However, none of the methods used achieved adequate discrimination between LC patients and patients with abnormal computed tomography (CT) findings. Biomarker sets, consisting mainly of the exogenous monoaromatic compounds and 1- and 2- propanol, adequately discriminated LC patients from healthy controls. The breath concentrations of these compounds may reflect the alterations in patient's physiological and biochemical status and perhaps can be used as probes for the investigation of these statuses or normalization of patient-related factors in breath analysis.