Association of BMI with pulmonary function, functional capacity, symptoms, and quality of life in ILD

Integrating the assessment of quality of life in care and research in pulmonary fibrosis

PURPOSE OF REVIEW

Pulmonary fibrosis (PF) negatively influences health-related quality of life (HRQOL). Patients living with PF have voiced the desire for a focus on symptoms and HRQOL in both disease monitoring and treatment decisions.

RECENT FINDINGS

Currently available disease modifying treatments do little to impact HRQOL. Newer studies evaluating pharmacologic and nonpharmacologic therapies targeting symptoms and HRQOL in PF have been conducted with some promising results. There is increasing recognition of the importance of incorporating HRQOL as a higher tier endpoint in clinical trials. Disease-specific measure of HRQOL have been developed for those living with PF, and there is ongoing work to better understand the validity and reliability characteristics of these tools. In addition to research, there is recognition of the potential benefits of measuring HRQOL and symptoms in clinical practice in facilitate integrating patient perspective into care and allow for more personalized treatment approaches.

SUMMARY

There is increased momentum to discover treatments that impact HRQOL in PF. More work is desperately needed to identify better treatment targets, and to incorporate HRQOL and symptoms as higher tier endpoints in clinical trials. Further work is also needed to address the practicalities of integrating HRQOL measurement into clinical care.

Determinants of cough-related quality of life in interstitial lung diseases

BACKGROUND

Interstitial lung diseases (ILD) include a wide range of diseases impacting lung parenchyma and leading to fibrosis and architectural distortion. Chronic cough and dyspnea are common symptoms which affect the quality of life (QoL) in ILD patients. The mechanisms of cough in ILD patients are still unknown. The aim of this study was to prospectively investigate histological, radiological, and physiological determinants of cough-related QoL in ILD patients who underwent transbronchial lung cryobiopsy (TBLC).

METHODS

All patients (n = 111) filled in The Leicester Cough Questionnaire (LCQ) and The St George's Respiratory Questionnaire (SGRQ). They underwent lung function tests, forced vital capacity (FVC), forced vital expiratory volume in 1 s (FEV1), diffusion capacity to carbon monoxide (DLCO), high-resolution computed tomography (HRCT), and blood samples before diagnostic TBLC. Two experienced radiologists assessed the extents of following HRCT patterns: ground-glass opacities (GGO), honeycombing, reticulation, traction bronchiectasis, and emphysema. Histology of TBLC were re-analyzed by two experienced pulmonary pathologists and the presence of fibroblast foci, fibrosis, giant cells, granulomas, and honeycombing were recorded.

RESULTS

In the median multivariate regression analysis, BMI (-0.19; 95% CI -0.37- -0.014; p 0.035), GGO (-0.38; 95% CI -0.61- -0.15; p 0.001), granulomas (-3.21; 95% CI -6.12- -0.30; p 0.031), and current smoking (2.49; 95% CI 0.12-4.86; p 0.040) showed independent associations with LCQ total score. BMI (1.3; 95% CI 0.20-2.42; p 0.021) and DLCO (-0.51; 95% CI -0.85 - -0.16; p 0.004) showed independent association with SGRQ total score.

CONCLUSION

Determinants of cough-related QoL in ILD patients are multifactorial including physiological, radiological and histological parameters.

Body mass index affects spirometry indices in patients with chronic obstructive pulmonary disease and asthma

Background: Body mass index (BMI) is known to affect the outcomes of spirometry indices. However, its association with spirometry indices in COPD and asthma is less studied. We aimed to explore the impact of BMI on these patients. Methods: Patients with COPD or asthma who completed bronchodilator tests (BDTs) between 2017 and 2021 were reviewed. Spirometry indices were compared among patients with COPD or asthma that were subclassified as underweight (BMI< 18.5 kg/m2), normal weight (≥18.5 to < 25), overweight (≥ 25 to < 30), and obesity (≥ 30). Results. Results: Analysis was conducted on 3891 COPD patients (age:66.5 ± 7.8 years) and 1208 asthma patients (age:59.7 ± 7.5 years). COPD patients classified as underweight demonstrated significantly lower values of pre-and post FEV1 (L, %), pre-and post FVC (L, %), and pre- and post-FEV1/FVC (all p < 0.05). In contrast, COPD patients who were overweight or obese exhibited higher values for pre-and post FEV1 (L, %), and pre and post FEV1/FVC (all p < 0.05). Within the cohort of asthma patients, those underweight had lower pre-and post FEV1 (L, %), pre and post FVC (L, %), pre and post FEV1/FVC %. Obese asthma patients displayed higher pre and post FEV1/FVC (all p < 0.05). Conclusion: Significant BMI category differences in spirometry indices can be seen in patients with COPD or asthma. Both underweight and obesity could affect the diagnosis and severity of these diseases. Recognizing these effects is essential to better management and diagnosis of these patients.

Treatable traits: a comprehensive precision medicine approach in interstitial lung disease

Interstitial lung disease (ILD) is a diverse group of inflammatory and fibrotic lung conditions causing significant morbidity and mortality. A multitude of factors beyond the lungs influence symptoms, health-related quality of life, disease progression and survival in patients with ILD. Despite an increasing emphasis on multidisciplinary management in ILD, the absence of a framework for assessment and delivery of comprehensive patient care poses challenges in clinical practice. The treatable traits approach is a precision medicine care model that operates on the premise of individualised multidimensional assessment for distinct traits that can be targeted by specific interventions. The potential utility of this approach has been described in airway diseases, but has not been adequately considered in ILD. Given the similar disease heterogeneity and complexity between ILD and airway diseases, we explore the concept and potential application of the treatable traits approach in ILD. A framework of aetiological, pulmonary, extrapulmonary and behavioural and lifestyle treatable traits relevant to clinical care and outcomes for patients with ILD is proposed. We further describe key research directions to evaluate the application of the treatable traits approach towards advancing patient care and health outcomes in ILD.

Telomere length associates with chronological age and mortality across racially diverse pulmonary fibrosis cohorts

Pulmonary fibrosis (PF) is characterized by profound scarring and poor survival. We investigated the association of leukocyte telomere length (LTL) with chronological age and mortality across racially diverse PF cohorts. LTL measurements among participants with PF stratified by race/ethnicity were assessed in relation to age and all-cause mortality, and compared to controls. Generalized linear models were used to evaluate the age-LTL relationship, Cox proportional hazards models were used for hazard ratio estimation, and the Cochran-Armitage test was used to assess quartiles of LTL. Standardized LTL shortened with increasing chronological age; this association in controls was strengthened in PF (R = -0.28; P < 0.0001). In PF, age- and sex-adjusted LTL below the median consistently predicted worse mortality across all racial groups (White, HR = 2.21, 95% CI = 1.79-2.72; Black, HR = 2.22, 95% CI = 1.05-4.66; Hispanic, HR = 3.40, 95% CI = 1.88-6.14; and Asian, HR = 2.11, 95% CI = 0.55-8.23). LTL associates uniformly with chronological age and is a biomarker predictive of mortality in PF across racial groups.

Weight loss and outcomes in subjects with progressive pulmonary fibrosis: data from the INBUILD trial

BACKGROUND

Lower body mass index (BMI) and weight loss have been associated with worse outcomes in some studies in patients with pulmonary fibrosis. We analyzed outcomes in subgroups by BMI at baseline and associations between weight change and outcomes in subjects with progressive pulmonary fibrosis (PPF) in the INBUILD trial.

METHODS

Subjects with PPF other than idiopathic pulmonary fibrosis were randomized to receive nintedanib or placebo. In subgroups by BMI at baseline (< 25, ≥ 25 to < 30, ≥ 30 kg/m²), we analyzed the rate of decline in FVC (mL/year) over 52 weeks and time-to-event endpoints indicating disease progression over the whole trial. We used a joint modelling approach to assess associations between change in weight and the time-to-event endpoints.

RESULTS

Among 662 subjects, 28.4%, 36.6% and 35.0% had BMI < 25, ≥ 25 to < 30 and ≥ 30 kg/m², respectively. The rate of decline in FVC over 52 weeks was numerically greater in subjects with baseline BMI < 25 than ≥ 25 to < 30 or ≥ 30 kg/m² (nintedanib: - 123.4, - 83.3, - 46.9 mL/year, respectively; placebo: - 229.5; - 176.9; - 171.2 mL/year, respectively). No heterogeneity was detected in the effect of nintedanib on reducing the rate of FVC decline among these subgroups (interaction p = 0.83). In the placebo group, in subjects with baseline BMI < 25, ≥ 25 to < 30 and ≥ 30 kg/m², respectively, 24.5%, 21.4% and 14.0% of subjects had an acute exacerbation or died, and 60.2%, 54.5% and 50.4% of subjects had ILD progression (absolute decline in FVC % predicted ≥ 10%) or died over the whole trial. The proportions of subjects with these events were similar or lower in subjects who received nintedanib versus placebo across the subgroups. Based on a joint modelling approach, over the whole trial, a 4 kg weight decrease corresponded to a 1.38-fold (95% CI 1.13, 1.68) increase in the risk of acute exacerbation or death. No association was detected between weight loss and the risk of ILD progression or the risk of ILD progression or death.

CONCLUSIONS

In patients with PPF, lower BMI at baseline and weight loss may be associated with worse outcomes and measures to prevent weight loss may be required.

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02999178 .

Contribution of obesity to breathlessness in a large nationally representative sample of Australian adults

BACKGROUND AND OBJECTIVE

Breathlessness is prevalent and associated with medical consequences. Obesity is related to breathlessness. However, the magnitude of its contribution has not been clearly documented. This investigation aimed to determine the contribution of obesity to breathlessness by estimating the population attributable fraction (PAF) in a representative sample of Australian adults.

METHODS

A cross-sectional, nationally representative survey of Australian residents aged ≥18 years was conducted in October 2019. Breathlessness was defined as modified Medical Research Council (mMRC) dyspnoea scale grade ≥2. BMI was calculated from self-reported height and weight. Adjusted relative risks (aRRs) were estimated using a generalized linear model with Poisson distribution, adjusted for age group and/or participant-reported diagnosed illnesses. Adjusted PAFs were estimated using aRR and obesity prevalence in Australian adults.

RESULTS

Among those who completed the National Breathlessness Survey, 9769 participants (51.4% female) were included in the analysis; 28.1% of participants were obese. The prevalence of breathlessness was 9.54%. The aRR of obesity for breathlessness was 2.04, adjusted for age. Adjusting for various co-morbid conditions, the aRR was slightly attenuated to around 1.85-1.98. The PAF, adjusted only for age, was 24.6% (95% CI 20.1-29.1) and after further adjustment for co-morbid conditions, the PAF ranged from 21.1% to 23.6%. Obesity accounted for a higher proportion of breathlessness in women than in men.

CONCLUSION

Our results demonstrate that obesity accounts for around a quarter of breathlessness symptoms in Australian adults. This has important implications for health policy in light of the global trend in increasing obesity.