Predictors of benefit following pulmonary rehabilitation for interstitial lung disease

SummaryBackgroundPulmonary rehabilitation improves functional capacity and symptoms in the interstitial lung diseases (ILDs), however there is marked variation in outcomes between individuals. The aim of this study was to establish the impact of the aetiology and severity of ILD on response to pulmonary rehabilitation.MethodsForty-four subjects with ILD, including 25 with idiopathic pulmonary fibrosis (IPF), underwent eight weeks of pulmonary rehabilitation. Relationships between disease aetiology, markers of disease severity and response to pulmonary rehabilitation were assessed after eight weeks and six months, regardless of program completion.ResultsIn IPF, greater improvements in 6-minute walk distance (6MWD) immediately following pulmonary rehabilitation were associated with larger forced vital capacity (r = 0.49, p = 0.01), less exercise-induced oxyhaemoglobin desaturation (rS = 0.43, p = 0.04) and lower right ventricular systolic pressure (r = −0.47, p = 0.1). In participants with other ILDs there was no relationship between change in 6MWD and baseline variables. Less exercise-induced oxyhaemoglobin desaturation at baseline independently predicted a larger improvement in 6MWD at six month follow-up. Fewer participants with IPF had clinically important reductions in dyspnoea at six months compared to those with other ILDs (25% vs 56%, p = 0.04). More severe dyspnoea at baseline and diagnosis other than IPF predicted greater improvement in dyspnoea at six months.ConclusionsPatients with IPF attain greater and more sustained benefits from pulmonary rehabilitation when disease is mild, whereas those with other ILDs achieve benefits regardless of disease severity. Early referral to pulmonary rehabilitation should be considered in IPF

Impaired chronotropic response to 6-min walk test and reduced survival in interstitial lung disease

SummaryBackgroundReduced chronotropic response to maximal exercise has been associated with poor survival in people without respiratory disease. The contribution of chronotropic response to exercise limitation and survival in interstitial lung disease (ILD) is not well defined. This study investigated the relationships between chronotropic response during 6-min walk test, exercise capacity and survival in ILD.MethodsEligible participants had ILD, were ambulant and free of heart failure and beta blocker therapy. Chronotropic response during the 6-min walk test was defined as peak heart rate (HR) minus resting HR. Survival was recorded at four years.ResultsSixty-two participants (40 idiopathic pulmonary fibrosis) were included, with mean (SD) TLCO 50(18)% predicted and 6-min walk distance (6MWD) 377 (127) metres. A smaller chronotropic response was associated with reduced 6MWD (r = 0.65, p < 0.001). Independent predictors of 6MWD were chronotropic response, peak oxygen uptake on cardiopulmonary exercise test; right ventricular systolic pressure on echocardiogram; and age. This model explained 83% of the variance in 6MWD, with 24% of the variance attributable to chronotropic response. A chronotropic response during 6-min walk test of less than 20 beats per minute was an independent predictor of death at four years (odds ratio 10.71, 95% confidence interval 2.67–42.94) in a model that also included oxygen desaturation and forced vital capacity.ConclusionsImpaired chronotropic response to 6-min walk test is associated with reduced 6MWD and reduced survival in ILD, independent of physical fitness and pulmonary hypertension. Investigation of the mechanisms underlying attenuated HR response to exercise in ILD is warranted

Incidence and prognostic significance of hypoxemia in fibrotic interstitial lung disease: an international cohort study.

BACKGROUND Hypoxemia is a cardinal feature of fibrotic interstitial lung disease (ILD). The incidence, progression, and prognostic significance of hypoxemia in patients with fibrotic ILD is currently unknown. RESEARCH QUESTION What are the epidemiology of hypoxemia and its additive prognostic value in current risk prediction model in fibrotic ILD? METHODS We identified 848 patients with fibrotic ILD (258 with idiopathic pulmonary fibrosis (IPF)) in five prospective ILD registries from Australia, Canada, and Switzerland. Cumulative incidence of exertional and resting hypoxemia from the time of diagnosis was estimated at 1-year intervals in patients with baseline 6-minute walk tests, adjusted for competing risks of death and lung transplantation. Likelihood ratio tests were used to determine the prognostic significance of exertional and resting hypoxemia for 1-year mortality/transplantation when added to the ILD-GAP model. The cohort was divided into derivation and validation subsets to evaluate performance characteristics of the extended model (the "ILD-GAP-O2" model), which included oxygenation status as a predictor. RESULTS The 1-, 2-, and 5-year overall cumulative incidence was 6.1%, 17.3%, and 40.1% for exertional hypoxemia, and 2.4%, 5.6%, and 16.5% for resting hypoxemia, which were significantly higher in IPF patients compared to non-IPF patients (p<0.001 for both). Addition of exertional or resting hypoxemia to the ILD-GAP model improved 1-year mortality/transplantation prediction (p<0.001 for both). The ILD-GAP-O2 model had improved discrimination (C-index of 0.80 vs 0.75) and model fit (Akaike information criteria of 400 vs 422) in the validation cohort, with comparable calibration. INTERPRETATION IPF patients have higher cumulative incidence of exertional and resting hypoxemia than non-IPF patients. The extended ILD-GAP-O2 model provides additional risk stratification for 1-year prognosis in fibrotic ILD

An empirical approach to the nucleation of sulfuric acid droplets in the atmosphere

We use quantum mechanical evaluations of the Gibbs free energy of the hydrates of sulfuric acid, H2SO4. nH2O and (H2SO4)2 . nH2O to evaluate an empirical surface tension for sulfuric acid-water clusters containing few molecules. We use this surface tension to evaluate nucleation rates using classical heteromolecular theory. At low temperatures (T 213 K) the nucleation rates obtained with the empirical surface tensions are signifi cantly greater than those using bulk values of the surface tension. At higher temperatures the difference disappears

Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: An international case-cohort study

We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts.A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κw). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index.A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κw=0.65, IQR 0.53–0.72, p less than 0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κw=0.54, IQR 0.45–0.64, p less than 0.0001). The prognostic accuracy of academic physicians with greater than 20 years of experience (C-index=0.72, IQR 0.0–0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70–0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72–0.75).Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts

Grupo Comunitário de Porto Alegre - Leigos para o Desenvolvimento

Comunicação apresentada no 3º Encontro Conhecimento e Cooperação, INA, Lisboa, 17 de setembro de 201

The human cellular response to peanut (Arachis hypogaea) and cross-reacting tree-nuts

Abstract not availabl