Body composition, muscle function, and physical performance in fibrotic interstitial lung disease: a prospective cohort study

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.

Association between body fat decrease during the first year after diagnosis and the prognosis of idiopathic pulmonary fibrosis: CT-based body composition analysis

BACKGROUND

The prognostic role of changes in body fat in patients with idiopathic pulmonary fibrosis (IPF) remains underexplored. We investigated the association between changes in body fat during the first year post-diagnosis and outcomes in patients with IPF.

METHODS

This single-center, retrospective study included IPF patients with chest CT scan and pulmonary function test (PFT) at diagnosis and a one-year follow-up between January 2010 and December 2020. The fat area (cm2, sum of subcutaneous and visceral fat) and muscle area (cm2) at the T12-L1 level were obtained from chest CT images using a fully automatic deep learning-based software. Changes in the body composition were dichotomized using thresholds dividing the lowest quartile and others, respectively (fat area: -52.3 cm2, muscle area: -7.4 cm2). Multivariable Cox regression analyses adjusted for PFT result and IPF extent on CT images and the log-rank test were performed to assess the association between the fat area change during the first year post-diagnosis and the composite outcome of death or lung transplantation.

RESULTS

In total, 307 IPF patients (69.3 ± 8.1 years; 238 men) were included. During the first year post-diagnosis, fat area, muscle area, and body mass index (BMI) changed by -15.4 cm2, -1 cm2, and - 0.4 kg/m2, respectively. During a median follow-up of 47 months, 146 patients had the composite outcome (47.6%). In Cox regression analyses, a change in the fat area < -52.3 cm2 was associated with composite outcome incidence in models adjusted with baseline clinical variables (hazard ratio [HR], 1.566, P = .022; HR, 1.503, P = .036 in a model including gender, age, and physiology [GAP] index). This prognostic value was consistent when adjusted with one-year changes in clinical variables (HR, 1.495; P = .030). However, the change in BMI during the first year was not a significant prognostic factor (P = .941). Patients with a change in fat area exceeding this threshold experienced the composite outcome more frequently than their counterparts (58.4% vs. 43.9%; P = .007).

CONCLUSION

A ≥ 52.3 cm2 decrease in fat area, automatically measured using deep learning technique, at T12-L1 in one year post-diagnosis was an independent poor prognostic factor in IPF patients.

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.

Therapeutic Approaches for the Treatment of Interstitial Lung Disease: An Exploratory Review on Molecular Mechanisms

BACKGROUND

Interstitial Lung Diseases (ILDs) are characterized by shortness of breath caused by alveolar wall inflammation and/or fibrosis.

OBJECTIVE

Our review aims to study the depth of various variants of ILD, diagnostic procedures, pathophysiology, molecular dysfunction and regulation, subject and objective assessment techniques, pharmacological intervention, exercise training and various modes of delivery for rehabilitation.

METHOD

Articles are reviewed from PubMed and Scopus and search engines.

RESULTS

ILD is a rapidly progressing disease with a high mortality rate. Each variant has its own set of causal agents and expression patterns. Patients often find it challenging to self-manage due to persistent symptoms and a rapid rate of worsening. The present review elaborated on the pathophysiology, risk factors, molecular mechanisms, diagnostics, and therapeutic approaches for ILD will guide future requirements in the quest for innovative and tailored ILD therapies at the molecular and cellular levels.

CONCLUSION

The review highlights the rationale for conventional and novel therapeutic approaches for better management of ILD.

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.

Integrative analyses for the identification of idiopathic pulmonary fibrosis-associated genes and shared loci with other diseases

BACKGROUND

Although genome-wide association studies (GWAS) have identified many genomic regions associated with idiopathic pulmonary fibrosis (IPF), the causal genes and functions remain largely unknown. Many single-cell expression data have become available for IPF, and there is increasing evidence suggesting a shared genetic basis between IPF and other diseases.

METHODS

We conducted integrative analyses to improve the power of GWAS. First, we calculated global and local genetic correlations to identify IPF genetically associated traits and local regions. Then, we prioritised candidate genes contributing to local genetic correlation. Second, we performed transcriptome-wide association analysis (TWAS) of 44 tissues to identify candidate genes whose genetically predicted expression level is associated with IPF. To replicate our findings and investigate the regulatory role of the transcription factors (TF) in identified candidate genes, we first conducted the heritability enrichment analysis in TF binding sites. Then, we examined the enrichment of the TF target genes in cell-type-specific differentially expressed genes (DEGs) identified from single-cell expression data of IPF and healthy lung samples.

FINDINGS

We identified 12 candidate genes across 13 genomic regions using local genetic correlation, including the POT1 locus (p value=0.00041), which contained variants with protective effects on lung cancer but increasing IPF risk. We identified another 13 novel genes using TWAS. Two TFs, MAFK and SMAD2, showed significant enrichment in both partitioned heritability and cell-type-specific DEGs.

INTERPRETATION

Our integrative analysis identified new genes for IPF susceptibility and expanded the understanding of the complex genetic architecture and disease mechanism of IPF.

Prevalence and assessment of frailty in interstitial lung disease - a systematic review and meta-analysis

BACKGROUND

Frailty is a multisystem dysregulation that challenges homeostasis and increases vulnerability towards stressors. In patients with interstitial lung diseases (ILD) frailty is associated with poorer lung function, greater physical impairment, and higher symptom burden. Our understanding of the prevalence of frailty in ILD and consequently its impact on the ILD population is limited.

OBJECTIVE AND METHODS

We aimed to systematically review frailty assessment tools and to determine frailty prevalence across different ILD cohorts. Meta-analyses were used to calculate the pooled prevalence of frailty in the ILD population.

RESULTS

We identified 26 studies (15 full-texts, 11 conference abstracts) including a total of 4614 patients with ILD. The most commonly used frailty assessment tools were the Fried Frailty Phenotype (FFP), the Short Physical Performance Battery (SPPB), and the cumulative Frailty Index (FI). Data allowed for meta-analyses of FFP and SPPB prevalence. The pooled prevalence of frailty was 35% (95% CI 25%-45%) by FFP, and 19% (95% CI 12%-28%) by SPPB.

CONCLUSIONS

Frailty is common in ILD, with considerable variability of frailty prevalence depending on the frailty assessment tool used. These findings highlight the importance of frailty in ILD and the need for a standardized approach to frailty assessment in this population.

Determinants of Six-Minute Walk Distance in Idiopathic Pulmonary Fibrosis and Idiopathic Pleuroparenchymal Fibroelastosis

Background: In idiopathic pulmonary fibrosis (IPF), 6-minute walking distance (6MWD) is an independent factor for mortality. Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a rare disease with physical features such as emaciation, but the relationship between IPPFE and 6MWD is unclear. In this study, we investigated the factors that cause a decrease in the percent of the predicted value of a 6-minute walk distance (%6MWD), including the disease entities, IPF and IPPFE. Methods: This study included 100 patients (IPF: 75 patients, IPPFE: 25 patients, age: 73.5 ± 7.2 years, sex: 73 males) who visited the rehabilitation department. Patients with a %6MWD ≥ 80% were assigned to the normal group (n = 54), and patients with a %6MWD < 80% were assigned to the decreased group (n = 46). The items showing a significant difference between groups were used as independent variables, after the consideration of multicollinearity, for a logistic analysis where %6MWD < 80% was used as the dependent variable. Results: The 6MWD results show that there was no significant difference between IPF and IPPFE in the absolute value of 6MWD and in the number of people with 6MWD ≥ 250 m, but when 6MWD was compared with %6MWD, the IPPFE group showed a significantly lower value than the IPF group (p = 0.013). Logistic regression analysis showed that only BMI (p = 0.032), GAP index (p = 0.043), and mMRC (p = 0.026) were factors that caused a decrease in %6MWD in 100 patients. Conclusion: The results suggest that leanness, shortness of breath and severity of illness are the most important factors that determine exercise tolerance, regardless of disease entity in IPF and IPPFE.

Predictors and changes of physical activity in idiopathic pulmonary fibrosis

Background

Different clinical predictors of physical activity (PA) have been described in idiopathic pulmonary fibrosis (IPF), but studies are lacking evaluating the potential role of muscle strength and anxiety and depression symptoms in PA limitation. Moreover, little is known about the impact of changes in PA in the course of the disease. The aim of the present study was to investigate the relationship between baseline PA and a wide range of variables in IPF, to assess its longitudinal changes at 12 months and its impact on progression free-survival.

Methods

PA was assessed by accelerometer and physiological, clinical, psychological factors and health-related quality of life were evaluated in subjects with IPF at baseline and at 12 month follow-up. Predictors of PA were determined at baseline, evolution of PA parameters was described and the prognostic role of PA evolution was also established.

Results

Forty participants with IPF were included and 22 completed the follow-up. At baseline, subjects performed 5765 (3442) daily steps and spent 64 (44) minutes/day in moderate to vigorous PA. Multivariate regression models showed that at baseline, a lower six-minute walked distance, lower quadriceps strength (QMVC), and a higher depression score in the Hospital Anxiety and Depression scale were associated to lower daily step number. In addition, being in (Gender-Age-Physiology) GAP III stage, having a BMI ≥ 25 kg/m² and lower QMVC or maximum inspiratory pressure were factors associated with sedentary behaviour. Adjusted for age, gender and forced vital capacity (FVC) (%pred.) a lower progression-free survival was evidenced in those subjects that decreased PA compared to those that maintained, or even increased it, at 12 months [HR 12.1 (95% CI, 1.9–78.8); p = 0.009].

Conclusion

Among a wide range of variables, muscle strength and depression symptoms have a predominant role in PA in IPF patients. Daily PA behaviour and its evolution should be considered in IPF clinical assessment and as a potential complementary indicator of disease prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02134-4.

Sarcopenia in idiopathic pulmonary fibrosis: a prospective study exploring prevalence, associated factors and diagnostic approach

Background

Sarcopenia gained importance in the evaluation of patients with chronic respiratory diseases, including idiopathic pulmonary fibrosis (IPF), since it may impact negatively on clinical outcomes.

Aim

Aim of this study is to evaluate the prevalence and factors associated with sarcopenia, defined according to the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) 2019 definition, and to evaluate the prevalence of the single criteria that define the EWGSOP2 definition (muscle strength, muscle quantity and physical performance), in a cohort of consecutive patients with IPF prospectively followed up in 9 hospitals in Northern Italy between December 2018 and May 2021.

Methods

Enrolled patients underwent an extensive pulmonary and nutritional assessment, including bioelectrical impedance analysis, dynamometry and 4-m gait speed test, both at IPF diagnosis and at 6-month follow-up.

Results

Out of the 83 patients (81% males, mean age 72.5 years) with IPF at disease diagnosis enrolled in the study, 19 (22.9%) showed sarcopenia, including 2 (2.4%) with severe sarcopenia, 5 (6.0%) with confirmed sarcopenia and 12 (14.5%) with probable sarcopenia. Sarcopenia was associated with a significantly higher severity of the disease and sedentary lifestyle, while no differences were observed in regards to body mass index, history of weight loss and comorbidities between patients with and without sarcopenia. Out of the 64 patients without sarcopenia at baseline, 16 cases showed alteration of muscle quantity and/or physical performance. In the 51 patients with complete data at 6-month follow-up, there were no cases of severe sarcopenia, 1 case (2.0%) showed confirmed sarcopenia, while the prevalence of probable sarcopenia was 19.6% (10 cases). No differences in regards to antifibrotic treatment received and onset of gastrointestinal side effects were observed between patients with and without sarcopenia at follow-up.

Conclusions

The prevalence of sarcopenia in patients with IPF both at diagnosis and at 6-month follow-up was low but not negligible and was associated with higher severity of the disease and sedentary lifestyle. In IPF patients, a comprehensive diagnostic work-up including all the criteria defining the EWGSOP2 definition might be more useful than a series testing for prompt recognition of nutritional and physical performance abnormalities.

High Prevalence of Nutritional Risk Among Pulmonary Patients Living on the Tibetan Plateau

Background

Nutritional risk is associated with adverse clinical outcomes and is more prevalent among pulmonology patients than among patients in other departments. High-altitude environments can affect patients with chronic respiratory diseases, but evidence of the prevalence of nutritional risk among hospitalized patients with respiratory diseases in high-altitude areas is limited. This study aimed to investigate the nutritional risk and status of inpatients with different major respiratory diagnoses permanently living on the Tibetan Plateau (≥3,000 m above sea level).

Methods

In this cross-sectional study, we consecutively recruited inpatients admitted to the Department of Respiratory and Critical Care Medicine at the Tibet Autonomous Region People's Hospital of Lhasa between November 2020 and May 2021. We used the Nutrition Risk Screening (NRS) 2002 tool to assess nutritional risk among these patients. An NRS 2002 score ≥3 points indicates nutritional risk; a score ≥5 indicates high nutritional risk. According to NRS-2002 scores, patients were divided into three groups (NRS-2002 0–2, 3–4, and ≥5). The differences in age, sex, major respiratory diagnoses, comorbidities, body mass index, and laboratory findings among the groups were analyzed.

Results

A total of 289 eligible Tibetan patients were enrolled in the study, and 46.1% (133/246) of them were at nutritional risk (NRS-2002 score ≥3). Twenty-one (7.3%) patients were at high nutritional risk (NRS-2002 score ≥5). The proportions of patients at nutritional risk were relatively high among patients with lung cancer (58.8%), interstitial lung disease (58.3%), pulmonary embolism (52.9%), and tuberculosis (50.0%). Laboratory findings showed that patients with NRS-2002 scores of 3–4 and ≥5 had lower red blood cell counts, serum albumin and hemoglobin levels, and higher C-reactive protein (CRP) levels than those with NRS-2002 scores < 3.

Conclusion

The prevalence of nutritional risk was high among pulmonology department inpatients permanently living on the Tibetan Plateau. Patients with lung cancer, interstitial lung disease, pulmonary embolism or tuberculosis were more likely to have nutritional risk than patients with other diagnoses. The nutritional risk of inpatients in the respiratory department in the plateau area should not be ignored, and patients at high nutritional risk should receive timely intervention.

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.

Management of Connective Tissue Disease-related Interstitial Lung Disease

Purpose of Review

This review aims to collate current evidence on the screening, diagnosis, and treatment of various connective tissue disease (CTD)–associated interstitial lung diseases (CTD-ILD) and present a contemporary framework for the management of such patients. It also seeks to summarize treatment outcomes including efficacy and safety of immunosuppressants, anti-fibrotics, and stem cell transplantation in CTD-ILD.

Recent Findings

Screening for ILD has been augmented by the use of artificial intelligence, ultra-low dose computerized tomography (CT) of the chest, and the use of chest ultrasound. Serum biomarkers have not found their way into clinical practice as yet. Identifying patients who need treatment and choosing the appropriate therapy is important to minimize the risk of therapy-related toxicity. The first-line drugs for systemic sclerosis (SSc) ILD include mycophenolate and cyclophosphamide. Nintedanib, an anti-fibrotic tyrosine kinase inhibitor, is approved for use in SSc-ILD. The US Food and Drug Administration (FDA) has recently approved tocilizumab subcutaneous injection for slowing the rate of decline in pulmonary function in adult patients with SSc-ILD. Autologous stem cell transplantation may have a role in select cases of SSc-ILD.

Summary

CTD-ILD is a challenging area with diverse entities and variable outcomes. High-resolution CT is the investigative modality of choice. Treatment decisions need to be individualized and are based on patient symptoms, lung function, radiologic abnormalities, and the risk of disease progression. Precision medicine may play an important role in determining the optimal therapy for an individual patient in the future.

Hypersensitivity pneumonitis: Current concepts in pathogenesis, diagnosis, and treatment

Hypersensitivity pneumonitis is an immune-mediated interstitial lung disease caused by an aberrant response to an inhaled exposure, which results in mostly T cell-mediated inflammation, granuloma formation, and fibrosis in some cases. HP is diagnosed by exposure identification, HRCT findings of ground-glass opacities, centrilobular nodules, and mosaic attenuation, with traction bronchiectasis and honeycombing in fibrotic cases. Additional testing including serum IgG testing for the presence of antigen exposure, bronchoalveolar lavage lymphocytosis, and lung biopsy demonstrating granulomas, inflammation, and fibrosis, increases the diagnostic confidence. Treatment for HP includes avoidance of the implicated exposure, immunosuppression, and anti-fibrotic therapy in select cases. This narrative review presents the recent literature in the understanding of the immunopathological mechanisms, diagnosis, and treatment of HP.

Clinical significance of pectoralis muscle strength in elderly patients with idiopathic pulmonary fibrosis

Introduction

Investigations of muscle dysfunction in patients with idiopathic pulmonary fibrosis (IPF) are limited to peripheral muscles. However, decreased thoracic muscle mass is known and deterioration of chest wall muscle strength is not clear.

Objective

The aims of the present study were to evaluate pectoralis muscle strength located on the chest wall and to investigate the relationship of spirometric measurements and respiratory muscle strength with pectoralis muscle strength.

Methods

Elderly patient with IPF (mean disease duration 7.47±7.04 years) and the age-and sex-matched healthy volunteers were recruited in this cross-sectional study. The pulmonary function test was performed by a portable spirometer for spirometric variables and a gas analyzer for diffusing capacity for carbon monoxide (DL_CO). Maximal inspiratory (MIP) and expiratory pressure (MEP) were measured with mouth pressure device. Modified Medical Research Council Dyspnea Scale (MMRC) was used to determined dyspnea severity. The pectoralis muscle strength was assessed isometrically during shoulder joint horizontal adduction movement with a handheld dynamometer.

Results

A total of 17 patients with IPF (9 males, mean age 69.06±3.94 years) and 19 healthy controls (10 males, mean age 70.95 ±4.99 years) were included. Patients with IPF had lower pectoralis muscle strength than healthy controls (p<0.001). Significant relationships were found between pectoralis muscle strength and MIP (r=0.79, p<0.001), MEP (r=0.81, p<0.001), FEV₁% (r=0.54, p=0.02), FVC% (r=0.68, p<0.003) and DL_CO (r=0.61, p=0.009). With multiple linear regression analysis, pectoralis muscle strength was the only independent predictor of FVC% (adjusted R²=0.37, p<0.05).

Conclusion

In patients with IPF, pectoralis muscle strength decreases and is associated with pulmonary function. In particular pectoralis muscle strength is likely to have an important impact on FVC%. Therefore, we consider that this test should be included routinely in chest diseases and rehabilitation clinics. The trial was registered U.S. National Library of Medicine clinical trial registry (https://clinicaltrials.gov, Trial ID: NCT04803617).

Comparison of heart rates at fixed percentages and the ventilatory thresholds in patients with interstitial lung disease

Heart rate (HR) responses to maximal exercise are commonly used for the prescription of training intensities in pulmonary rehabilitation. Those intensities are usually based on fixed percentages of peak HR (HRpeak), heart rate reserve (HRR), or peak work load (Wpeak), and rarely on HRs at the individual ventilatory thresholds (VT1 and VT2) derived from cardiopulmonary exercise testing (CPET). For patients suffering from interstitial lung disease (ILD), data on cardiorespiratory responses to CPET are scarce. Thus, the aim of this study was to record cardiorespiratory responses to CPET and to compare fixed HR percentages with HRs at VT1 and VT2 in ILD patients. A total of 120 subjects, 80 ILD patients and 40 healthy controls, underwent a symptom‐limited CPET. From the ILD patient, 32 suffered from idiopathic pulmonary fibrosis (IPF), 37 from connective tissue disease (CTD), and 11 from sarcoidosis. HRs at fixed percentages, that is, at 70%HRpeak, at 70%Wpeak, and at 60%HRR were significantly lower in the ILD patients compared with the control group (p‐values: 0.001, 0.044, and 0.011). Large percentages of HR values at 70%Wpeak and 60%HRR ranged between the HRs at VT1 and VT2 in ILD subgroups and controls as well. HRs at 70%HRpeak were lower than HRs at VT1 in 66% of the IPF patients, 54% of the CTD patients, and 55% of patients with sarcoidosis compared with 18% in the control group. Our findings demonstrate a considerable scattering of fixed HR percentages compared with HRs at the individual VTs derived from CPET in ILD patients. These findings may provide valuable information for the prescription of exercise intensity in pulmonary rehabilitation of ILD patients.

Exercise-Based Pulmonary Rehabilitation for Interstitial Lung Diseases: A Review of Components, Prescription, Efficacy, and Safety

Interstitial lung diseases (ILDs) comprise a heterogeneous group of disorders (such as idiopathic pulmonary fibrosis, sarcoidosis, asbestosis, and pneumonitis) characterized by lung parenchymal impairment, inflammation, and fibrosis. The shortness of breath (i.e., dyspnea) is a hallmark and disabling symptom of ILDs. Patients with ILDs may also exhibit skeletal muscle dysfunction, oxygen desaturation, abnormal respiratory patterns, pulmonary hypertension, and decreased cardiac function, contributing to exercise intolerance and limitation of day-to-day activities. Pulmonary rehabilitation (PR) including physical exercise is an evidence-based approach to benefit functional capacity, dyspnea, and quality of life in ILD patients. However, despite recent advances and similarities with other lung diseases, the field of PR for patients with ILD requires further evidence. This mini-review aims to explore the exercise-based PR delivered around the world and evidence supporting prescription modes, considering type, intensity, and frequency components, as well as efficacy and safety of exercise training in ILDs. This review will be able to strengthen the rationale for exercise training recommendations as a core component of the PR for ILD patients.

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.

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.

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.

Frailty in patients with interstitial lung disease

PURPOSE OF REVIEW

The incidence of age-related diseases such as interstitial lung disease (ILD) is rising, and the importance of multimorbidity and accumulation of health deficits in patients with chronic lung diseases is increasingly recognized. There are multiple relationships between aging and ILD on a demographic and a biological level. Frailty conceptualizes the decline of a patient's physiological reserves and complements the chronological and biological aspects of aging.

RECENT FINDINGS

Frailty affects more than 50% of patients with ILD, with respiratory impairment, accelerated biological aging, comorbidities, medication adverse effects, and social factors collectively playing important roles. Frailty is an independent risk factor for adverse health outcomes such as hospitalizations and early mortality, including before and after lung transplant. Given the multicomponent determinants of frailty, programs such as pulmonary rehabilitation are promising strategies for managing this complex issue.

SUMMARY

Frailty is a common risk factor for adverse outcomes in patients with ILD. The multiple pathways leading to frailty are not completely understood, and further studies are needed to determine the optimal tools for assessment and to develop strategies to prevent and counteract frailty in the aging ILD population.

Functional performance tests in interstitial lung disease: Impairment and measurement properties

BACKGROUND

There is limited information regarding impairment in functional performance tests and their measurement properties in ILD. The present study aimed to verify the impairment and measurement properties of functional performance tests in ILD.

METHODS

ILD and healthy individuals underwent assessments of pulmonary function, peripheral muscle strength (handgrip force and maximum isometric contraction of quadriceps femoris - MIVCq) and exercise capacity (6-min walk test - 6MWT). Functional performance was assessed by timed-up-and-go with usual (TUGu) and fast (TUGf) gait speeds, 4-m gait speed (4MGS), sit-to-stand in 30 s (30sec-STS), 1 min (1min-STS) and with 5 repetition (5rep-STS) and Short Physical Performance Battery (SPPB). Functional performance was compared between groups, validity (correlation with 6MWT and MIVCq) and reliability of tests were checked in subjects with ILD (intra- and inter-rater agreement analysis).

RESULTS

Seventy-six participants (40 ILD [25 women, 61 ± 11 years, FVC 75 ± 17 %pred] and 36 healthy [22 women, 61 ± 9 years, FVC 97 ± 11 %pred]) were included. Functional performance in ILD was worse than in healthy individuals in all tests, except for the 30sec-STS (p = 0.13). Pre-specified validity criteria were reached for TUGu, TUGf, 4MGS and 5rep-STS (-0.69 < r < 0.55; p < 0.05 for all). Except for 4MGS and SPPB, all tests showed good to excellent inter-rater (0.85 < ICC<0.93; p < 0.05 for all) and all tests showed good to excellent intra-rater (0.83 < ICC< 0.94; p < 0.05 for all) reliability.

CONCLUSIONS

Subjects with ILD present worse functional performance than healthy individuals. According to reliability and validity results, TUGu, TUGf and 5rep-STS seem to be the most appropriate tests to evaluate functional performance in ILD.

Relationship between handgrip strength and lung function in adults: a systematic review

Handgrip strength (HGS) is a functional test that has been directly associated with lung function in some healthy populations; however, inconsistent findings have been reported for populations with chronic diseases. The aim of this study was to identify the relationship between HGS and lung function in both healthy and unhealthy adults. A systematic search was conducted using six databases from their earliest inception to February 29, 2020. Two authors reviewed and assessed methodological quality of eligible studies using the Crowe Critical Appraisal Tool (CCAT). Twenty-five studies met the inclusion criteria with 8 and 17 studies examining healthy and unhealthy populations, respectively. Reported average methodological quality of all included studies using the CCAT was 38-85% with most rated as Good to Excellent. Despite the use of heterogeneous equipment and protocols during HGS and lung function assessments, significant positive and moderate correlations and/or regression coefficients were reported for healthy populations consistently. Conversely, the reported relationships between HGS and lung function for unhealthy counterparts were variable. Handgrip strength was significantly associated with lung function in most healthy adults. Future robust studies are needed to confirm the suitability of HGS to assess lung function for healthy and unhealthy adults.

Treatment of chronic fibrosing interstitial lung diseases

Interstitial lung diseases (ILD) refers to a large and heterogenous group of parenchymal lung disorders. It is difficult to diagnose and classify ILD. Nevertheless, accurate diagnosis of ILD is crucial for appropriate treatment selection and prediction of prognosis. Idiopathic pulmonary fibrosis (IPF), the most severe of the chronic forms of ILD, is defined as a specific form of chronic, progressive fibrosing interstitial pneumonia of unknown cause. In addition to IPF, a subset of patients with ILD may develop progressive fibrotic changes in lungs. As pulmonary fibrosis progresses, lung function gradually deteriorates and respiratory symptoms worsen; besides, quality of life is also impaired. Progressive fibrosis is also associated with limited response to immunomodulatory thrapies and, potentially, early death. A progressive fibrosing phenotype of ILD (PF-ILD), a subtype of ILD, shows morphological similarities, common underlying pathophysiologic mechanisms, and consistently progressive worsening. PF-ILD include idiopathic nonspecific interstitial pneumonia, unclassifiable idiopathic interstitial pneumonia, autoimmune ILD, chronic sarcoidosis, chronic hypersensitivity pneumonitis and environmental lung diseases. Antifibrotic agents pirfenidone and nintedanib have showed positive results not only for IPF but also for PF-ILD. Immunosuppressive therapy can be used for some types of PF-ILD. If a patient with PF-ILD does not respond to conventional treatment, lung transplantation may be a treatment option. Clinical trials on the treatment of PF-ILD are actively underway. Therefore, over the course of the next several years, major advances in PF-ILD treatment can be expected.

Nutritional status and quality of life in interstitial lung disease: a prospective cohort study

Background

Malnutrition and altered body composition are well-documented in chronic pulmonary diseases; however, investigation of nutritional status in interstitial lung disease (ILD) is limited. This study aimed to describe the nutritional status of ILD patients within three diagnostic groups and explore the relationship between nutritional status and quality of life (QoL).

Methods

Consecutive patients attending an ILD clinic within a tertiary referral hospital in Sydney, Australia were studied. Weight, body-mass-index, anthropometrics, handgrip strength (HGS), subjective global assessment and QoL questionnaires (EQ-5D-5L and King’s-Brief Interstitial-Lung-Disease ‘K-BILD’) were collected. Associations between nutritional status and QoL were analysed.

Results

Ninety participants were recruited and categorised: (1) Idiopathic Pulmonary Fibrosis (IPF) (2) Connective-Tissue Disease associated-ILD (CTD-ILD) or (3) Other (non-IPF/non-CTD ILD). Median age was 66.5 (18) years. Four-percent of patients were underweight and 50% were overweight or obese. Median HGS was 71%-(25.3) of predicted and was correlated to all measures of QoL including EQ-5D health-state index (r = 0.376, p < 0.0001), patient-reported EQ-5D-5L Visual Analogue Score (r = 0.367, p < 0.0001) and K-BILD total score (r = 0.346, p = 0.001). Twenty-three percent of the variance in K-BILD total score (F = 12.888, p < 0.0001) was explained by HGS (ß = 0.273, p = 0.006) and forced vital capacity % predicted (ß = 0.331, p = 0.001).

Conclusions

Although a small number of ILD patients were malnourished, a large proportion of the cohort were overweight or obese. Handgrip strength was compromised and correlated to QoL. Future research with a larger cohort is required to explore the role of HGS as a predictor of QoL.

Reliability and validity of the Glittre-ADL test to assess the functional status of patients with interstitial lung disease

The study objective was to investigated the reliability and validity of the ADL-Glittre test (TGlittre) to assess the functional status of patients with interstitial lung disease (ILD). Twenty-one individuals with ILD participated (age: 63 ± 11 years; DLCO: 51.0 ± 12.6%predicted), evaluated with body plethysmography, Saint George Respiratory Questionnaire, modified Medical Research Council dyspnea scale, six-minute walk test (6MWT) and monitoring of physical activity of daily living. Two TGlittre were performed, with an interval of 30 minutes between them. The TGlittre demonstrated high test-retest reliability, with an intraclass correlation coefficient of 0.90 (95%CI: 0.75-0.96; p < 0.001). Nineteen patients (90.5%) performed better on the second test (mean difference between TGlittre 1 and 2: -0.57 ± 0.96 minute; p = 0.001), with a learning effect of 11.6%. The time in TGlittre correlated with 6MWT (r = -0.70; p = 0.002) and with the total energy expenditure in physical activity of daily living (r = -0.52; p = 0.02). In %predicted, TGlittre and 6MWT also correlated (r = -0.50; p = 0.04). Correlations were observed between TGlittre and pulmonary function variables (r = -0.47 to -0.57; p = 0.01 to p = 0.04). There was no difference in the physiological response between TGlittre 1 and 2, and between TGlittre and 6MWT (p > 0.05). In conclusion, the TGlittre is reliable and valid for assessing functional status of patients with ILD.

Impact of Body Mass Index on Activities of Daily Living in Patients with Idiopathic Interstitial Pneumonias

In patients with idiopathic interstitial pneumonias, undernutrition has a profound effect on prognosis. However, whether body mass index affects the ability to perform activities of daily living as measured by the Barthel index in patients with idiopathic interstitial pneumonias remains unknown. Therefore, we examined the impact of body mass index on the activities of daily living in inpatients with idiopathic interstitial pneumonia. We used a database constructed by the Japan Medical Data Center. Data were extracted from 2774 inpatients from participating hospitals with a diagnosis of idiopathic interstitial pneumonia. Multiple regression analysis adjusted for confounding factors was performed to determine whether body mass index classification would be independently related to change in Barthel index during hospitalization. Underweight, normal weight, overweight, and obesity numbered 473 (19%), 1037 (41), 795 (31%), and 235 (9%), respectively. Multivariable analysis showed that being underweight was independently associated with a change in Barthel index during hospitalization of −2.95 (95% confidence interval −4.82 to −1.07) points lower than being normal weight. Approximately 20% of the patients with idiopathic interstitial pneumonias were underweight. Those who were underweight had decreased independence in activities of daily living during hospitalization.

Nutrition in Patients with Idiopathic Pulmonary Fibrosis: Critical Issues Analysis and Future Research Directions

In idiopathic pulmonary fibrosis (IPF), several factors may have a negative impact on the nutritional status, including an increased respiratory muscles load, release of inflammation mediators, the coexistence of hypoxemia, and physical inactivity. Nutritional abnormalities also have an impact on IPF clinical outcomes. Given the relevance of nutritional status in IPF patients, we sought to focus on some critical issues, highlighting what is known and what should be further learned about these issues. We revised scientific literature published between 1995 and August 2019 by searching on Medline/PubMed and EMBASE databases including observational and interventional studies. We conducted a narrative review on nutritional assessment in IPF, underlining the importance of nutritional evaluation not only in the diagnostic process, but also during follow-up. We also highlighted the need to keep a high level of attention on cardiovascular comorbidities. We also focused on current clinical treatment in IPF with Nintedanib and Pirfenidone and management of gastrointestinal adverse events, such as diarrhea, induced by these antifibrotic drugs. Finally, we concentrated on the importance of pulmonary rehabilitation program, including nutritional assessment, education and behavioral change, and psychological support among its essential components. More attention should be devoted to the assessment of the undernutrition and overnutrition, as well as of muscle strength and physical performance in IPF patients, taking also into account that an adequate clinical management of gastrointestinal complications makes IPF drug treatments more feasible.

Nutrition in Patients with Idiopathic Pulmonary Fibrosis: Critical Issues Analysis and Future Research Directions

In idiopathic pulmonary fibrosis (IPF), several factors may have a negative impact on the nutritional status, including an increased respiratory muscles load, release of inflammation mediators, the coexistence of hypoxemia, and physical inactivity. Nutritional abnormalities also have an impact on IPF clinical outcomes. Given the relevance of nutritional status in IPF patients, we sought to focus on some critical issues, highlighting what is known and what should be further learned about these issues. We revised scientific literature published between 1995 and August 2019 by searching on Medline/PubMed and EMBASE databases including observational and interventional studies. We conducted a narrative review on nutritional assessment in IPF, underlining the importance of nutritional evaluation not only in the diagnostic process, but also during follow-up. We also highlighted the need to keep a high level of attention on cardiovascular comorbidities. We also focused on current clinical treatment in IPF with Nintedanib and Pirfenidone and management of gastrointestinal adverse events, such as diarrhea, induced by these antifibrotic drugs. Finally, we concentrated on the importance of pulmonary rehabilitation program, including nutritional assessment, education and behavioral change, and psychological support among its essential components. More attention should be devoted to the assessment of the undernutrition and overnutrition, as well as of muscle strength and physical performance in IPF patients, taking also into account that an adequate clinical management of gastrointestinal complications makes IPF drug treatments more feasible.

Progression of fibrosing interstitial lung disease

Fibrotic interstitial lung diseases (ILDs) are often challenging to diagnose and classify, but an accurate diagnosis has significant implications for both treatment and prognosis. A subset of patients with fibrotic ILD experience progressive deterioration in lung function, physical performance, and quality of life. Several risk factors for ILD progression have been reported, such as male sex, older age, lower baseline pulmonary function, and a radiological or pathological pattern of usual interstitial pneumonia. Morphological similarities, common underlying pathobiologic mechanisms, and the consistently progressive worsening of these patients support the concept of a progressive fibrosing (PF)-ILD phenotype that can be applied to a variety of ILD subtypes. The conventional approach has been to use antifibrotic medications in patients with idiopathic pulmonary fibrosis (IPF) and immunosuppressive medications in patients with other fibrotic ILD subtypes; however, recent clinical trials have suggested a favourable treatment response to antifibrotic therapy in a wider variety of fibrotic ILDs. This review summarizes the literature on the evaluation and management of patients with PF-ILD, and discusses questions relevant to applying recent clinicial trial findings to real-world practice.