Rituximab and mycophenolate mofetil combination in patients with interstitial lung disease (EVER-ILD): a double-blind, randomised, placebo-controlled trial.

BACKGROUND: Standard of care for interstitial lung disease (ILD) with a nonspecific interstitial pneumonia (NSIP) pattern proposes mycophenolate mofetil (MMF) as one of the first-step therapies while rituximab is used as rescue therapy. METHODS: In a randomised, double-blind, two-parallel group, placebo-controlled trial (NCT02990286), patients with connective tissue disease-associated ILD or idiopathic interstitial pneumonia (with or without autoimmune features) and a NSIP pattern (defined on NSIP pathological pattern or on integration of clinicobiological data and a NSIP-like high-resolution computed tomography pattern) were randomly assigned in a 1:1 ratio to receive rituximab (1000 mg) or placebo on day 1 and day 15 in addition to MMF (2 g daily) for 6 months. The primary end-point was the change in percent predicted forced vital capacity (FVC) from baseline to 6 months analysed by a linear mixed model for repeated measures analysis. Secondary end-points included progression-free survival (PFS) up to 6 months and safety. FINDINGS: Between January 2017 and January 2019, 122 randomised patients received at least one dose of rituximab (n=63) or placebo (n=59). The least-squares mean change from baseline to 6 months in FVC (% predicted) was +1.60 (se 1.13) in the rituximab+MMF group and -2.01 (se 1.17) in the placebo+MMF group (between-group difference 3.60, 95% CI 0.41-6.80; p=0.0273). PFS was better in the rituximab+MMF group (crude hazard ratio 0.47, 95% CI 0.23-0.96; p=0.03). Serious adverse events occurred in 26 (41%) patients of the rituximab+MMF group and in 23 (39%) of the placebo+MMF group. Nine infections were reported in the rituximab+MMF group (five bacterial infections, three viral infections, one other) and four bacterial infections in the placebo+MMF group. INTERPRETATION: Combination of rituximab and MMF was superior to MMF alone in patients with ILD and a NSIP pattern. The use of this combination must take into consideration the risk of viral infection.

Did COVID-19 impact Positive Airway Pressure adherence in 2020? A cross-sectional study of 8477 patients with sleep apnea.

BACKGROUND: Whether the COVID-19 pandemic impacts Positive Airway Pressure (PAP) adherence over the long-term is unknown and only preliminary short-term data have been reported. METHODS: With the aim of describing the impact of the first and second waves of COVID-19 on PAP adherence during 2020 in France, we designed a cross-sectional study of Sleep-Apnea (SA)-patients under PAP telemonitoring. To examine PAP adherence in adult SA patients, we assessed de-identified data from a non-profit healthcare provider database during the period January 1, 2019 to December 31, 2020. Included patients met the following criteria: (i) PAP-treated for at least 4 months before January 1, 2019 and with continuous PAP during both 2019 and 2020; (ii) ≥ 360 daily PAP telemonitored data per year. For PAP adherence, data were collected using the PAP-software. RESULTS: 8477/10482 patients were finally included in the analysis [72.4% male, median age 70 years (IQ25-75: 61-77], 25.6% < 62 years old, initial Apnea-Hypopnea Index (AHI) of 41 (31-59)/h. Median PAP adherence was 7.21 (6.12-8.10) h/day in 2020 versus 7.12 (6.05-8.02) h/day in 2019, p < 0.001. The median difference in PAP adherence between the first 2020 lockdown and the corresponding 2019 weeks was 9.75 (CI95% 8.75-10.75) min/day, p < 0.001. The median difference in PAP adherence between the second 2020 lockdown and the corresponding 2019 weeks was 5.00 (CI95% 4.00-6.00) min/day, p < 0.001. If we consider the minimal clinically important difference of 30 min for PAP adherence, 30.4% and 26% of the patients increased their PAP adherence by at least 30 min during the first and second lockdowns respectively; 17.6% and 19.3% of the patients lowered their PAP adherence by at least 30 min in the first and second lockdowns, respectively. CONCLUSION: During the first and second lockdowns, the COVID-19 pandemic had a clinically irrelevant effect on PAP adherence for the study population. Future studies are needed to describe COVID-19 pandemic impact on PAP adherence not only for long-term PAP-treated SA patients but also for incident cases. Trial registration The COVADENE study was registered on March 1st, 2021 on ClinicalTrials.gov (Identifier: NCT04775966).

Chest ultrasound findings in usual interstitial pneumonia patterns: a pilot study.

It is unknown what role chest ultrasound plays in distinguishing the various usual interstitial pneumonia (UIP) patterns of high-resolution chest tomography (HRCT). The purpose of this study was to see if there was a link between the results of chest ultrasound (u/s) and HRCT in patients with idiopathic pulmonary fibrosis (IPF). We performed chest u/s in 16 patients with UIP and probable UIP patterns to indeterminate UIP and alternative diagnosis patterns in this single center prospective study to determine any possible relationship with the HRCT findings. A chest radiologist reviewed each HRCT to determine the pattern in accordance with the American Thoracic Society (ATS) / European Respiratory Society (ERS) Guidelines. The local multidisciplinary committee validated the patients' diagnoses before they were included. When compared to the indeterminate for UIP or alternative diagnosis pattern group, there was a trend (p=0.07) toward the presence of more B lines in UIP or probable UIP patterns. There was no statistically significant difference in the presence of small, large, white lung, or pleural line thickening >5mm. Subgroup analysis revealed that patients with honeycombing were more likely to have a fragmented pleural line (p=0.04). To summarize, in our pilot study, chest u/s appears unable to differentiate UIP and probable UIP patterns from indeterminate UIP and alternative diagnosis patterns. However, it appears that this technique can be used to recognize the honeycombing pattern.

Relationship between gender and survival in a real-life cohort of patients with COPD.

BACKGROUND: Although COPD affects both men and women, its prevalence is increasing more rapidly in women. Disease outcomes appear different among women with more frequent dyspnea and anxiety or depression but whether this translates into a different prognosis remains to be determined. Our aim was to assess whether the greater clinical impact of COPD in women was associated with differences in 3-year mortality rates. METHODS: In the French Initiatives BPCO real-world cohort, 177 women were matched up to 458 menon age (within 5-year intervals) and FEV1 (within 5% predicted intervals). 3-year mortality rate and survival were analyzed. Univariate and multivariate logistic regression analyses were performed. RESULTS: For a given age and level of airflow obstruction, women with COPD had more severe dyspnea, lower BMI, and were more likely to exhibit anxiety. Nevertheless, three-year mortality rate was comparable among men and women, respectively 11.2 and 10.8%. In a multivariate model, the only factors significantly associated with mortality were dyspnea and malnutrition but not gender. CONCLUSION: Although women with COPD experience higher levels of dyspnea and anxiety than men at comparable levels of age and FEV1, these differences do not translate into variations in 3-year mortality rates. TRIAL REGISTRATION: 04-479.

Phrenic Nerve Conduction in Healthy Subjects.

INTRODUCTION: Assessment of diaphragm compound muscle action potential by noninvasive phrenic nerve stimulation at the neck is well described. However, normal values in a large cohort of healthy subjects are lacking. Our objective was to determine reference values of phrenic nerve conduction in healthy subjects. METHODS: We recruited 155 healthy subjects (25-79 years old) and measured mean amplitude (PhrenAmp) and latency (PhrenLat) of motor responses according to Bolton's method. RESULTS: The lower limit for PhrenAmp was 0.28 and 0.25 mV and the upper limit for PhrenLat was 8.41 and 8.56 ms for right and left side, respectively. PhrenLat was correlated with age. PhrenAmp, PhrenLat and area were significantly higher in men. Tolerance to phrenic nerve stimulation was excellent. CONCLUSIONS: Our study provides normative values of phrenic nerve motor responses in a large cohort of healthy subjects and identifies age and sex as factors of variation. Muscle Nerve 59:451-456, 2019.

Impact of gender on COPD expression in a real-life cohort.

Reports regarding gender-related differences in COPD expression have provided conflicting results. In the French Initiatives BPCO real-world cohort, which contained 688 patients (146 women) when data were extracted, women were matched with men (1:3 ratio: n = 107:275) on age (5-year intervals) and FEV1 (5% predicted intervals) and comparisons were performed using univariate logistic regressions. For a given age and level of airflow obstruction, women with COPD had higher BOD scores due to more pronounced dyspnea and lower BMI, suggesting worse prognosis, and were more likely to exhibit anxiety, suggesting the need for specific assessment and care.

Association of chronic nasal symptoms with dyspnoea and quality-of-life impairment in chronic obstructive pulmonary disease.

BACKGROUND AND OBJECTIVE: Previous studies suggested that chronic nasal symptoms (CNS) are frequent in chronic obstructive pulmonary disease (COPD) subjects, but their contribution to dyspnoea and quality-of-life (QoL) impairment is not clearly established. METHODS: Data from the French COPD cohort 'Initiatives bronchopneumopathie chronique obstructive' were analyzed to assess the frequency of CNS (rhinorrhea, obstruction, anosmia) in COPD patients and analyze their impact and associated risk factors. Univariate and multivariate analyses were performed to assess the relationship between CNS with sociodemographic and anthropometric characteristics, risk factors, respiratory symptoms, spirometry, QoL (Saint George's respiratory questionnaire (SGRQ)), dyspnoea (modified Medical Research Council (mMRC) scale), mood disorders (Hospital Anxiety and Depression Scale (HADS)), number of exacerbations and comorbid conditions. RESULTS: CNS were reported by 115 of 274 COPD subjects (42%). Among them, rhinorrhea and nasal obstruction were reported by 62% and 43%, respectively. In multivariate analysis, COPD patients with CNS had higher SGRQ total scores, corresponding to worse QoL (P = 0.01), while no independent association was found with exacerbations, lung function and HADS. Among SGRQ domains, an independent association was found with the activity score (P = 0.007). When SGRQ score was forced out of the model to avoid redundancy, mMRC score was independently associated with CNS (P = 0.01). Among risk factors, cumulative smoking, hay fever and atopic dermatitis but not occupational exposures were independently associated with CNS. CONCLUSIONS: In this group of COPD subjects, CNS were frequently observed and associated with dyspnoea and poorer QoL. CNS should be systematically assessed and could be a potential target in the management of COPD.

Long-term adherence with non-invasive ventilation improves prognosis in obese COPD patients.

BACKGROUND AND OBJECTIVE: Long-term non-invasive ventilation (NIV) has become a widespread modality of treatment in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure. However, benefits in terms of patient-related outcomes are still under debate. Both NIV adherence and heterogeneous responses in different COPD phenotypes may contribute to the difficulty of demonstrating NIV benefits. Our aim was to assess the impact of NIV adherence on the rate of hospitalization for acute exacerbation and death. METHODS: This is a prospective multi-centre cohort study of COPD patients treated by long-term NIV. Comorbidities, anthropometrics, respiratory parameters were collected at inclusion in the study. Follow-up data included vital status, NIV adherence and hospitalizations. The influence of NIV adherence on prognosis was tested using an adjusted Cox model. Sensitivity analyses for obese and non-obese COPD subtypes were also conducted. RESULTS: Two hundred thirteen patients (48% obese) were included with 45.5% died during 47.7 [interquartile range = 27.8; 73] months' follow-up. Survival was better in obese COPD than non-obese COPD. The use of NIV > 9 h/day was associated with an increased risk of death or hospitalization for acute exacerbation [HR = 1.6; 95CI: 1.1-2.4]. In obese COPD, this risk described a U-shaped curve from >1 to >9 h/day NIV usage with an improvement in prognosis when NIV adherence was > 5 h/day [HR = 0.5; 95CI: 0.2-0.9]. CONCLUSIONS: Adherence to NIV was associated with better prognosis only in obese COPD. NIV use > 9 h/day predicted poor outcomes.

French recommendations for the diagnosis and management of lymphangioleiomyomatosis.

BACKGROUND: The present article is an English-language version of the French National Diagnostic and Care Protocol, a pragmatic tool to optimize and harmonize the diagnosis, care pathway, management and follow-up of lymphangioleiomyomatosis in France. METHODS: Practical recommendations were developed in accordance with the method for developing a National Diagnosis and Care Protocol for rare diseases of the Haute Autorité de Santé and following international guidelines and literature on lymphangioleiomyomatosis. It was developed by a multidisciplinary group, with the help of patient representatives and of RespiFIL, the rare disease network on respiratory diseases. RESULTS: Lymphangioleiomyomatosis is a rare lung disease characterised by a proliferation of smooth muscle cells that leads to the formation of multiple lung cysts. It occurs sporadically or as part of a genetic disease called tuberous sclerosis complex (TSC). The document addresses multiple aspects of the disease, to guide the clinicians regarding when to suspect a diagnosis of lymphangioleiomyomatosis, what to do in case of recurrent pneumothorax or angiomyolipomas, what investigations are needed to make the diagnosis of lymphangioleiomyomatosis, what the diagnostic criteria are for lymphangioleiomyomatosis, what the principles of management are, and how follow-up can be organised. Recommendations are made regarding the use of pharmaceutical specialties and treatment other than medications. CONCLUSION: These recommendations are intended to guide the diagnosis and practical management of pulmonary lymphangioleiomyomatosis.

Association between occupational exposure and the clinical characteristics of COPD.

BACKGROUND: The contribution of occupational exposures to COPD and their interaction with cigarette smoking on clinical pattern of COPD remain underappreciated. The aim of this study was to explore the contribution of occupational exposures on clinical pattern of COPD. METHODS: Cross-sectional data from a multicenter tertiary care cohort of 591 smokers or ex-smokers with COPD (median FEV1 49%) were analyzed. Self-reported exposure to vapor, dust, gas or fumes (VDGF) at any time during the entire career was recorded. RESULTS: VDGF exposure was reported in 209 (35%) subjects aged 31 to 88 years. Several features were significantly associated with VDGF exposure: age (median 68 versus 64 years, p < 0.001), male gender (90% vs 76%; p < 0.0001), reported work-related respiratory disability (86% vs 7%, p < 0.001), current wheezing (71% vs 61%, p = 0.03) and hay fever (15.5% vs 8.5%, p < 0.01). In contrast, current and cumulative smoking was less (p = 0.01) despite similar severity of airflow obstruction. CONCLUSION: In this patient series of COPD patients, subjects exposed to VDGF were older male patients who reported more work-related respiratory disability, more asthma-like symptoms and atopy, suggesting that, even in smokers or ex-smokers with COPD, occupational exposures are associated with distinct patients characteristics.

The effect of a pressure ventilatory support on quadriceps endurance is maintained after exercise training in severe COPD patients. A longitudinal randomized, cross over study.

Purpose: In severe chronic obstructive pulmonary disease (COPD) patients, the application of an inspiratory pressure support (IPS) during exercise increases exercise tolerance and the benefit of exercise training during pulmonary rehabilitation (PR). Moreover, it improves quadriceps endurance after a session of cycling exercise suggesting a reduced muscle fatigue. We looked for the persistence of this effect after PR and sought an association between the improved quadriceps endurance with IPS and the training load during PR. Patients and methods: We studied 20 patients with severe COPD (6 in stage 3and 14 in stage 4 of GOLD) before and after PR. As part of a PR program, patients completed 16 cycling sessions over 6 weeks with the addition of IPS during exercise. As a surrogate of muscular fatigue, quadriceps endurance was measured at 70% of maximal strength in a control condition, after a constant work rate exercise test (CWR) with IPS (TlimQ IPS) or with a sham ventilation (TlimQsham), in a random order. These tests were repeated similarly at the end of PR. Results: PR was associated with a significant increase in maximal power output, cycling endurance, quadriceps strength and endurance. Session training load (power output x duration of the session) increased by 142% during the course of the program. Before PR, CWR duration increases with IPS compared to sham ventilation (Δtime = +244s, p = 0.001). Compared to control condition, post-exercise TlimQ reduction was lower with IPS at isotime than at the end of CWR or than with sham ventilation (-9 ± 21%, -18 ± 16% and -23 ± 18%, respectively, p = 0.09, p < 0.0001 and p < 0.0001). After PR, the post-exercise decrease of TlimQ was reduced after IPS compared to sham (-9 ± 18% vs. -21 ± 17%, respectively, p = 0.004). No relationship was found between the prevention of quadriceps fatigue and the training load. Conclusion: In severe COPD patients, the beneficial effect of a ventilator support on quadriceps endurance persisted after PR with IPS. However, it was not related to the increase in training load, and could not predict the training response to non-invasive ventilation during exercise.

Multimodal nutritional rehabilitation improves clinical outcomes of malnourished patients with chronic respiratory failure: a randomised controlled trial.

BACKGROUND: In chronic respiratory failure (CRF), body composition strongly predicts survival. METHODS: A prospective randomised controlled trial was undertaken in malnourished patients with CRF to evaluate the effects of 3 months of home rehabilitation on body functioning and composition. 122 patients with CRF on long-term oxygen therapy and/or non-invasive ventilation (mean (SD) age 66 (10) years, 91 men) were included from eight respiratory units; 62 were assigned to home health education (controls) and 60 to multimodal nutritional rehabilitation combining health education, oral nutritional supplements, exercise and oral testosterone for 90 days. The primary endpoint was exercise tolerance assessed by the 6-min walking test (6MWT). Secondary endpoints were body composition, quality of life after 3 months and 15-month survival. RESULTS: Mean (SD) baseline arterial oxygen tension was 7.7 (1.2) kPa, forced expiratory volume in 1 s 31 (13)% predicted, body mass index (BMI) 21.5 (3.9) kg/m2 and fat-free mass index (FFMI) 15.5 (2.4) kg/m2. The intervention had no significant effect on 6MWT. Improvements (treatment effect) were seen in BMI (+0.56 kg/m2, 95% CI 0.18 to 0.95, p=0.004), FFMI (+0.60 kg/m2, 95% CI 0.15 to 1.05, p=0.01), haemoglobin (+9.1 g/l, 95% CI 2.5 to 15.7, p=0.008), peak workload (+7.2 W, 95% CI 3.7 to 10.6, p<0.001), quadriceps isometric force (+28.3 N, 95% CI 7.2 to 49.3, p=0.009), endurance time (+5.9 min, 95% CI 3.1 to 8.8, p<0.001) and, in women, Chronic Respiratory Questionnaire (+16.5 units, 95% CI 5.3 to 27.7, p=0.006). In a multivariate Cox analysis, only rehabilitation in a per-protocol analysis predicted survival (HR 0.27, 95% CI 0.07 to 0.95, p=0.042). CONCLUSIONS: Multimodal nutritional rehabilitation aimed at improving body composition increased exercise tolerance, quality of life in women and survival in compliant patients, supporting its incorporation in the treatment of malnourished patients with CRF. Clinical Trial number NCT00230984.

Use of high-frequency peak in spectral analysis of heart rate increment to improve screening of obstructive sleep apnoea.

PURPOSE: Several studies have correlated the ratio of the very low frequency power spectral density of heart rate increment (%VLFI) with obstructive sleep apnoea syndrome (OSAS). However, patients with impaired heart rate variability may exhibit large variations of heart rate increment (HRI) spectral pattern and alter the screening accuracy of the method. METHODS: To overcome this limitation, the present study uses the high-frequency increment (HFI) peak in the HRI spectrum, which corresponds to the respiratory influence on RR variations over the frequency range 0.2 to 0.4 Hz. We evaluated 288 consecutive patients referred for snoring, observed nocturnal breathing cessation and/or daytime sleepiness. Patients were classified as OSAS if their apnoea plus hypopnoea index (AHI) during polysomnography exceeded 15 events per hour. Synchronized electrocardiogram Holter monitoring allowed HRI analysis. RESULTS: Using a %VLFI threshold >2.4% for identifying the presence of OSAS, sensitivity for OSAS was 74.9%, specificity 51%, positive predictive value 54.9% and negative predictive value 71.7% (33 false negative subjects). Using threshold for %VLFI >2.4% and HFI peak position >0.4 Hz, negative predictive value increased to 78.2% while maintaining specificity at 50.6%. Among 11 subjects with %VLFI <2.4% and HFI peak >0.4 Hz, nine demonstrated moderate to severe OSAS (AHI >30). CONCLUSIONS: HFI represents a minimal physiological criterion for applying %VLFI by ensuring that heart rate variations are band frequency limited.

Sleep disturbances and related disordered breathing after hip replacement surgery: A randomised controlled trial.

INTRODUCTION: Mechanisms of postoperative sleep architecture disturbances and sleep-disordered breathing are uncertain. The authors hypothesised that patients undergoing surgery under regional anaesthesia without opioids used for postoperative analgesia would experience lesser changes in these parameters than patients operated under general anaesthesia with per- and postoperative opioids. PATIENTS AND METHODS: After ethical approval and informed consent, patients undergoing total hip replacement were included in a prospective, randomised trial comparing 3 groups of patients: (1) S-LPB group receiving spinal anaesthesia and postoperative analgesia by lumbar plexus block; (2) GA-PCA group receiving general anaesthesia and postoperative analgesia by morphine patient-controlled analgesia; (3) GA-LPB group receiving general anaesthesia and postoperative analgesia by lumbar plexus block. Outcome measurements were polysomnographic parameters of sleep architecture and sleep-disordered breathing. RESULTS: Eighteen patients completed the 5-night study protocol (preoperative night: N-1, postoperative nights: N1 to N4). The percentage of rapid eye movement (REM) sleep decreased by 49% and 47% during N1 in the GA-PCA and GA-LPB groups respectively. A rebound phenomenon of more than 40% in the GA-PCA group and 25% in the GA-LPB group was observed during N2 and N3. Apnoea hypopnoea index (AHI) and the number of arousals per hour were significantly increased during N2 and N3 when compared with N-1 in the GA-groups. No sleep architecture disturbances and no sleep-disordered breathing were measured in the S-LPB group. CONCLUSION: Postoperative sleep architecture and breathing pattern were disturbed in GA groups. Both were preserved under spinal anaesthesia associated with a free opioid postoperative analgesia.

Insulin Resistance and Type 2 Diabetes in Asymptomatic Obstructive Sleep Apnea: Results of the PROOF Cohort Study After 7 Years of Follow-Up.

The aim of the study was to assess potential associations between obstructive sleep apnea (OSA) and the occurrence of diabetes mellitus and insulin resistance in the elderly. Nondiabetic volunteers (n = 549) with undiagnosed or untreated asymptomatic OSA (66.2+/-1 years at the inclusion) were evaluated as an ancillary study of the PROOF cohort study (n = 1,011). After 7 years follow-up, 494 subjects underwent assessment of fasting insulin and glucose levels. OSA was defined by an apnea-hypopnea index (AHI) of ≥15/h using polygraphy. Diabetes mellitus was defined by a fasting glucose ≥ 1.26 g/L and/or when requiring pharmacological treatment, while insulin resistance corresponded to HOMA-IR ≥ 2. Asymptomatic OSA subjects (men or women) did not display increased risk of incident diabetes (2.8 vs. 3.9%, p = 0.51). However, there was a greater frequency of insulin resistance in subjects with severe OSA (AHI > 30) [OR 2.21; 95% CI (1.22-4.02); p = 0.009]. Furthermore, multiple logistic regression showed that triglycerides levels [OR 1.61; 95% CI (1.10-2.36); p = 0.01] and fasting glycaemia [OR 4.69; 95% CI (1.12-192.78); p = 0.04], but not AHI or oxyhemoglobin desaturation index were independently associated with higher rate of insulin resistance. The deleterious metabolic effect of asymptomatic OSA in the population may be indirectly mediated via perturbations in lipids, and is particularly likely to become manifest in severe apneic subjects with higher glycemic levels.

Burden and Characteristics of Severe Chronic Hypoxemia in a Real-World Cohort of Subjects with COPD.

BACKGROUND: Chronic respiratory failure may occur as a consequence of chronic obstructive pulmonary disease (COPD) and is associated with significant morbidity and mortality. Hypoxemia is determined by underlying disease characteristics and comorbidities. Severe hypoxemia is typically only found in subjects with severe airflow obstruction (FEV1<50% predicted). However, how hypoxemia relates to disease characteristics is not fully understood. METHODS: In the French Initiatives BPCO real-life cohort, arterial blood gases were routinely collected in most patients. Relationships between severe hypoxemia, defined by a Pa02<60 mmHg (8 kPa) and clinical/lung function features, comorbidities and mortality were assessed. In subjects with severe hypoxemia, clinical characteristics and comorbidities were compared between those with non-severe versus severe airflow limitation. Classification and regression trees (CART) were used to define clinically relevant subgroups (phenotypes). RESULTS: Arterial blood gases were available from 887 subjects, of which 146 (16%) exhibited severe hypoxemia. Compared to subjects with a PaO2≥60 mmHg, the severe hypoxemia group exhibited higher mMRC dyspnea score, lower FEV1, higher RV and RV/TLC, more impaired quality of life, lower 6-minute walking distance, less frequent history of asthma, more frequent diabetes and higher 3-year mortality rate (14% versus 8%, p=0.026). Compared to subjects with Pa02<60 mmHg and FEV1<50% (n=115, 13%), those with severe hypoxemia but FEV1≥50% predicted (n=31) were older, had higher BMI, less hyperinflation, better quality of life and a higher rate of diabetes (29% versus 13%, p=0.02). Severe hypoxemia was better related to CART-defined phenotypes than to GOLD ABCD classification. CONCLUSION: In this cohort of stable COPD subjects, severe hypoxemia was associated with worse prognosis and more severe symptoms, airflow limitation and hyperinflation. Compared to subjects with severe hypoxemia and severe airflow limitation, subjects with severe hypoxemia despite non-severe airflow limitation were older, had higher BMI and more diagnosed diabetes. TRIAL REGISTRATION: 04-479.

Predictors in routine practice of 6-min walking distance and oxygen desaturation in patients with COPD: impact of comorbidities.

Background: The 6-min walk test (6MWT) allows exercise tolerance to be assessed, and it has a significant prognostic value in COPD. The goal of this study was to analyse the determinants (obtained in routine practice) of a low 6-min walking distance (6MWD) and exercise-induced desaturation (EID) in COPD, including comorbidities. Methods: Patients were recruited from the real-life French COPD cohort "Initiatives BPCO". A low 6MWD was defined as <350 m. EID was defined by a minimum pulse oxygen saturation (SpO2)<90% and delta SpO2≥4% from baseline. Multivariate logistic regression analyses assessed the influence on 6MWD and EID of age, sex, obesity (body mass index, BMI >30 kg/m2), low BMI (BMI <18.5 kg/m2), modified Medical Research Council (mMRC) dyspnea scale, FEV1% pred, FVC % pred, hyperinflation and comorbidities including cardiovascular diseases. Results: Among 440 patients with available 6MWT data, a 6MWD <350 m was found in 146 patients (33%), which was positively associated in multivariate analyses with age and mMRC and negatively with resting SpO2 and FVC % pred (rescaled r2=0.34), whereas no comorbidity was associated with a low 6WMD. EID was found in 155 patients (35%). This was positively associated with hypertension and negatively with age, obesity, FEV1% pred and resting SpO2 (rescaled r2=0.37). Conclusion: 6MWD and EID exhibit different determinants in COPD with a minor impact of comorbidities limited to hypertension in EID and to obesity, which was unexpectedly associated with less EID. Other variables including age, routine resting lung function and SpO2 were weakly associated with 6MWD and EID. Altogether, these results suggest that 6MWT performance remains difficult to predict with routine clinical/functional parameters.

Quadriceps Endurance Increases Following Cycling Exercise With Non-Invasive Ventilation In Moderate-To-Severe COPD Patients. A Non-Randomized Controlled Study.

Purpose: Application of non-invasive ventilation (NIV) during exercise improves exercise tolerance in severe COPD patients; however, the underlying mechanism is only partially unraveled. As part of its known effect to unload the respiratory muscles, we looked for the influence of NIV on post-exercise quadriceps muscle endurance. Patients and methods: We included 25 severe COPD patients entering an outpatient pulmonary rehabilitation program. They performed, on successive days, three quadriceps endurance tests at 70% of the maximal strength (1RM) to task failure (TlimQ); 1) control condition; 2) following constant load cycling exercise to exhaustion without Inspiratory Pressure Support (TlimQ IPS-); 3) following the same cycling exercise with IPS (TlmQ IPS+). Results: Dyspnea Borg score was significantly reduced at the end of the constant load cycling exercise with IPS+ compared to IPS- (3.5±2.6 to 4.3±2.3, p<0.05). Compared to controlled condition, TlimQ was reduced from 78.9±22.7 s to 64.7±22.1 s (p<0.01) with IPS+ and to 48.9±13.7 s (p<0.001) with IPS-. Sensitive analysis revealed a positive effect of NIV on TlimQ in only 15 of the 25 included patients (60%) and was unpredictable from exercise tolerance or maximal quadriceps strength. Conclusion: Using a simple muscle endurance test, we showed the protective effect of NIV on the exercise-induced quadriceps dysfunction. This beneficial effect is inconstant in our small series of patients and could not be predicted by exercise capacity or endurance to exercise. However, measuring quadriceps muscle endurance following a session of exercise could determine in which patient NIV would improve the benefit of pulmonary rehabilitation.