Mild obstructive sleep apnoea in females: post hoc analysis of the MERGE randomised controlled trial.

Background: A post hoc analysis of the MERGE trial was conducted, to investigate whether sex differences are evident at the mildest end of the disease spectrum, for symptoms associated with obstructive sleep apnoea (OSA) and the response to continuous positive airway pressure (CPAP) treatment. Methods: MERGE participants with mild OSA (apnoea-hypopnoea index 5-15 events·h-1; American Academy of Sleep Medicine 2012 criteria) were randomised to either CPAP plus standard care (sleep hygiene counselling) or standard care alone for 3 months. Quality of life (QoL) was measured by questionnaires completed before and after the 3 months. This post hoc analysis of participants of the MERGE trial compared the symptom presentation, and response to CPAP, between the sexes. Results: 233 patients were included; 71 (30%) were female. Females were more symptomatic at baseline in all QoL questionnaires. Specifically, females had lower 36-item Short-Form Health Survey (SF-36) Vitality scores (mean±sd 39.1±10.1 versus 44.8±10.3) and higher Epworth Sleepiness Scale (ESS) scores (mean±sd 11.0±4.2 versus 9.5±4.4). Both sexes experienced snoring, but more females reported fatigue and more males reported witnessed apnoeas. All symptoms improved with CPAP for both sexes; however, females had larger improvements in SF-36 Vitality scores, which was the primary outcome of the MERGE trial (mean change 9.4 (95% CI 6.8-12.0) versus 6.0 (95% CI 4.3-7.7); p=0.034), and ESS (mean change -4.1 (95% CI -5.1- -3.0) versus -2.5 (95% CI -3.1- -1.8); p=0.015), after adjustment for baseline scores and CPAP usage. Conclusions: Sex differences are apparent in patients with mild OSA. Females experience worse QoL symptoms than males at presentation to the sleep clinic; however, these improve significantly with CPAP treatment.

Structural Predictors of Lung Function Decline in Young Smokers with Normal Spirometry.

RATIONALE: Chronic obstructive pulmonary disease (COPD) due to tobacco smoking commonly presents when extensive lung damage has occurred. OBJECTIVES: We hypothesised that structural change would be detected early in the natural history of COPD and would relate to loss of lung function with time. METHODS: We recruited 431 current smokers (median age 39 years, 16 pack-years smoked) and recorded symptoms by the COPD Assessment Test (CAT), spirometry and quantitative thoracic CT (QCT) scans at study entry. These scans results were compared to 67 never smoking controls. 368 participants were followed every six months with measurement of post-bronchodilator spirometry for a median of 32 months. The rate of FEV1 decline, adjusted for current smoking status, age and sex was related to the initial QCT appearances and symptoms, measured with the CAT. MEASUREMENTS AND MAIN RESULTS: There were no material differences in demography or subjective CT appearances between the young smokers and controls, but 55.7% of the former had a CAT score above 10 and 24.2% reported chronic bronchitis. QCT assessments of Disease Probability-defined functional small airways disease, ground glass opacification, bronchovascular prominence and small blood vessel to total pulmonary vessel volume ratio were increased compared to controls and were all associated with a faster FEV1 decline as was a higher CAT score. CONCLUSIONS: Radiologic abnormalities on CT are already established in young smokers with normal lung function and is associated with FEV1 loss independently of the impact of symptoms. Structural abnormalities are present early in the natural history of COPD and are markers of disease progression. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

A Double-Blind, Randomized, Placebo-controlled Trial of Long-Term Doxycycline Therapy on Exacerbation Rate in Patients with Stable Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) exacerbations are a major cause of morbidity and mortality, and preventing them is a key treatment target. Long-term macrolide treatment is effective at reducing exacerbations, but there is a paucity of evidence for other antibiotic classes. Objectives: To assess whether 12-month use of doxycycline reduces the exacerbation rate in people with COPD. Methods: People with moderate to very severe COPD and an exacerbation history were recruited from three UK centers and randomized to 12 months of doxycycline 100 mg once daily or placebo. The primary study outcome was the exacerbation rate per person-year. Results: A total of 222 people were randomized. Baseline mean FEV1 was 1.35 L (SD, 0.35 L), 52.5% predicted (SD, 15.9% predicted). The median number of treated exacerbations in the year before the study was 2 (SD, 1-4). A total of 71% of patients reported two or more exacerbations, and 81% were already prescribed inhaled corticosteroids at baseline. The COPD exacerbation rate did not differ between the groups (doxycycline/placebo rate ratio [RR], 0.86; 95% confidence interval [CI], 0.67-1.10; P = 0.23). No difference was seen if only treated exacerbations or hospitalizations were considered. In preplanned subgroup analysis, doxycycline appeared to better reduce the exacerbation rate among people with severe COPD (RR, 0.36; 95% CI, 0.15-0.85; P = 0.019) and in those with an eosinophil count <300 cells/µl (RR, 0.50; 95% CI, 0.29-0.84; P = 0.01). Health status measured by St. George's Respiratory Questionnaire was 5.2 points worse in the doxycycline group at 12 months (P < 0.007). Conclusions: Doxycycline did not significantly reduce the exacerbation rate, over 12 months, in participants with COPD who exacerbated regularly, but it may have benefitted those with more severe COPD or blood eosinophil counts <300 cells/µl. Clinical trial registered with www.clinicaltrials.gov (NCT02305940).

Contemporary Concise Review 2022: Chronic obstructive pulmonary disease.

International respiratory organizations now recommend using lower limit of normal and standardized residuals to diagnose airflow obstruction and COPD though using a fixed ratio <0.7 is simpler and robustly predicts important clinical outcomes. The most common COPD comorbidities are coronary artery calcification, emphysema and bronchiectasis. COPD patients with psychological (high anxiety and depression) and cachectic (underweight and osteoporotic) comorbidity have higher mortality and exacerbate more. Serum eosinophil count remains an important COPD biomarker and we have greater clarity about normal eosinophil levels in COPD and the wider population. Criteria for entry into COPD clinical trials continue to exclude many patients, in particular those at greater risk of exacerbation and death. The effect of hyperinflation on cardiac function impacts COPD mortality and is an important target for successful lung volume reduction procedures.

The Effect of Maintenance Treatment with Erdosteine on Exacerbation Treatment and Health Status in Patients with COPD: A Post-Hoc Analysis of the RESTORE Dataset.

Purpose: To explore the effect of erdosteine on COPD exacerbations, health-related quality of life (HRQoL), and subjectively assessed COPD severity. Patients and methods: This post-hoc analysis of the RESTORE study included participants with COPD and spirometrically moderate (GOLD 2; post-bronchodilator forced expiratory volume in 1 second [FEV1] 50‒79% predicted; n = 254), or severe airflow limitation (GOLD 3; post-bronchodilator FEV1 30‒49% predicted; n = 191) who received erdosteine 300 mg twice daily or placebo added to usual maintenance therapy for 12 months. Antibiotic and oral corticosteroid use was determined together with patient-reported HRQoL (St George's Respiratory Questionnaire, SGRQ). Patient and physician subjective COPD severity scores (scale 0‒4) were rated at baseline, 6 and 12 months. Data were analyzed using descriptive statistics for exacerbation severity, COPD severity, and treatment group. Comparisons between treatment groups used Student's t-tests or ANCOVA as appropriate. Results: Among GOLD 2 patients, 43 of 126 erdosteine-treated patients exacerbated (7 moderate-to-severe exacerbations), compared to 62 of 128 placebo-treated patients (14 moderate-to-severe exacerbations). Among those with moderate-to-severe exacerbations, erdosteine-treated patients had a shorter mean duration of corticosteroid treatment (11.4 days vs 13.3 days for placebo, P = 0.043), and fewer patients required antibiotic treatment with/without oral corticosteroids (71.4% vs 85.8% for placebo, P < 0.001). Erdosteine-treated GOLD 2 patients who exacerbated showed significant improvements from baseline in SGRQ total scores and subjective disease severity scores (patient- and physician-rated), compared with placebo-treated patients regardless of exacerbation severity. Among GOLD 3 patients, there were no significant differences between treatment groups on any of these measures. Conclusion: Adding erdosteine to the usual maintenance therapy of COPD patients with moderate airflow limitation reduced the number of exacerbations, the duration of treatment with corticosteroids and the episodes requiring treatment with antibiotics. Additionally, treatment with erdosteine improved HRQoL and patient-reported disease severity.

International Differences in the Frequency of Chronic Obstructive Pulmonary Disease Exacerbations Reported in Three Clinical Trials.

Rationale: Exacerbations of chronic obstructive pulmonary disease (COPD) are an important endpoint in multinational clinical treatment trials, but the observed event rate is often lower than anticipated and appears to vary between countries. Objectives: We investigated whether systematic differences in national exacerbation rates might explain this observed variation. Methods: We reviewed data from three large multicenter international randomized trials conducted over an 18-year period with different designs and clinical severities of COPD, comparing bronchodilator and/or inhaled corticosteroids with bronchodilators alone and/or placebo. Exacerbations were defined by antibiotic and/or oral corticosteroid use (moderate) or need for hospitalization (severe). We calculated crude exacerbation rates in the 30 countries contributing 30 or more patients to at least two trials. We grouped data by exacerbation rate based on their first study contribution. Measurements and Main Results: For the 29,756 patients in 41 countries analyzed, the mean exacerbation rate was two- to threefold different between the highest and lowest tertiles of the recruiting nations. These differences were not explained by demographic features, study protocol, or reported exacerbation history at enrollment. Of the 18 countries contributing to all trials, half of those in the highest and half in the lowest tertiles of exacerbation history remained in these groups across trials. Severe exacerbations showed a different rank order internationally. Conclusions: Countries contributing to COPD trials differ consistently in their reporting of healthcare-defined exacerbations. These differences help explain why large studies have been needed to show differences between treatments that decrease exacerbation risk.

A Pooled Analysis of Mortality in Patients with COPD Receiving Dual Bronchodilation with and without Additional Inhaled Corticosteroid.

Background: Recent studies report a lower mortality rate during treatment with long-acting muscarinic antagonist (LAMA)/long-acting ß2-agonist (LABA)/inhaled corticosteroid (ICS) versus LAMA/LABA in patients with symptomatic chronic obstructive pulmonary disease (COPD) and a history of exacerbations. Objective: We compared time to all-cause mortality with LAMA/LABA versus LAMA/LABA/ICS in patients with mild-to-very-severe COPD and a predominantly low exacerbation risk. Methods: Data were pooled from six randomized controlled trials (TONADO 1/2, DYNAGITO, WISDOM, UPLIFT and TIOSPIR; LAMA/LABA: n = 3156, LAMA/LABA/ICS: n = 11,891). Analysis was on-treatment and data were censored at 52 weeks. Patients on LAMA/LABA/ICS received ICS prior to study entry, which was not withdrawn at randomization. Patients on LAMA/LABA/ICS were propensity score (PS)-matched to patients on LAMA/LABA who had not previously received ICS; covariates included age, sex, geographical region, smoking status, post-bronchodilator forced expiratory volume in 1 second percent predicted, exacerbation history in previous year, body mass index and time since diagnosis. Time to all-cause mortality was assessed using Cox proportional hazard regression models. Results: After PS matching, 3133 patients on LAMA/LABA and 3133 patients on LAMA/LABA/ICS were analyzed. Fewer than 20% of patients reported ≥2 exacerbations in the prior year (LAMA/LABA: 19.1%; LAMA/LABA/ICS: 19.0%). There were 41 (1.3%) deaths on LAMA/LABA and 45 (1.4%) deaths on LAMA/LABA/ICS. No statistically significant difference in time to death was observed between treatment arms (hazard ratio for LAMA/LABA 1.06; 95% confidence intervals 0.68, 1.64; P = 0.806). Sensitivity analyses conducted using different covariates or in an intent-to-treat population showed similar results. Conclusion: This pooled analysis of over 6000 patients with mild-to-very-severe COPD and predominantly low exacerbation risk showed no differences in mortality with LAMA/LABA versus LAMA/LABA/ICS, suggesting that the survival benefit of triple therapy seen in some recent studies may be specific to a high-risk population. This supports current Global Initiative for Chronic Obstructive Lung Disease recommendations that triple therapy should be reserved for the subpopulations of patients who need it the most (eg, those with an eosinophilic phenotype and a high risk of exacerbations) to avoid ICS overuse.

Mortality and Exacerbation Risk by Body Mass Index in Patients with COPD in TIOSPIR and UPLIFT.

Rationale: There is an association between body mass index (BMI) and mortality in chronic obstructive pulmonary disease (COPD), with underweight individuals having higher mortality risk. Mortality and exacerbation risks among individuals with higher BMI are unclear. Objectives: To examine the relationship between BMI and adverse outcomes in COPD. Methods: This post hoc analysis included data from TIOSPIR (Tiotropium Safety and Performance in Respimat) (N = 17,116) and tiotropium-treated patients in UPLIFT (Understanding Potential Long-term Impacts on Function with Tiotropium) (N = 2,986). BMI classes (underweight [BMI < 20 kg/m2], normal weight [BMI 20 to <25 kg/m2], overweight [BMI 25 to <30 kg/m2], obesity class I [BMI 30 to <35 kg/m2], obesity class II [BMI 35 to <40 kg/m2], and obesity class III [BMI ⩾ 40 kg/m2]) were examined for adjusted associations with mortality, exacerbation, and nonfatal cardiovascular event risk using over 50,000 patient-years of cumulative follow-up data. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox regression models. Results: In TIOSPIR, obesity prevalence was 22%, overweight 32%, and underweight 12%. The proportion of females was highest in obesity classes II and III. Overweight and obese participants had better baseline lung function versus other BMI classes; underweight participants were more likely to be current smokers. Underweight participants had a significantly higher risk of death (HR, 1.88; 95% CI, 1.62-2.20; P < 0.0001) and severe exacerbations (HR, 1.31; 95% CI, 1.16-1.47; P < 0.0001) versus normal-weight participants; however, overweight and obese participants were at lower to no additional risk. Results from UPLIFT were similar to TIOSPIR. Conclusions: These results suggest that there is a strong association between body weight, COPD events, and risk of death. A holistic management approach taking into account respiratory and cardiovascular risk factors and nutritional status is needed to improve the general well-being of patients with COPD.

Impact of the UK lockdown on people at risk of COPD.

Impact of the UK lockdown on early COPD https://bit.ly/3laMsmi.

ACO (Asthma-COPD Overlap) Is Independent from COPD: The Case in Favour.

Over the last decade interest has been shown in people with symptomatic lung disease who have features both of COPD and asthma. In this review we examine how COPD and asthma are defined and examine clinical characteristics of people defined by researchers as having asthma-COPD overlap (ACO). We look at pathological and physiological features along with symptoms and consider the impact of each diagnosis upon therapeutic management. We highlight challenges in the diagnosis and management of airway disease and the various phenotypes that could be part of ACO, in so doing suggesting ways for the clinician to manage patients with features of both asthma and COPD.

Challenging the obesity paradox: extreme obesity and COPD mortality in the SUMMIT trial.

Populations with COPD demonstrate higher survival in overweight and obese compared with normal weight; the "obesity paradox". Relationships in less-severe COPD are unclear, as is the impact of cardiovascular risk, and few studies include individuals at extremes of obesity. We examined the relationship between body mass index (BMI; defined as underweight: <20 kg·m-2, normal: 20-25 kg·m-2, overweight: 25- <30 kg·m-2, obese class I: 30- <35 kg·m-2, class II: 35- <40 kg·m-2 and class III: ≥40 kg·m-2), morbidity, and mortality in the SUMMIT trial population (n=16 485), characterised by moderate COPD and heightened cardiovascular risk with a substantial proportion with class III obesity. The association between BMI category and time to event was modelled via proportional hazards (reference normal weight) adjusted for demographics and cardiorespiratory disease. Consistent with the paradox, underweight individuals demonstrated higher mortality (hazard ratio (HR) 1.31 (95% CI 1.04-1.64)), with lower mortality among overweight (HR 0.62 (95% CI 0.52-0.73)) and obese class I (HR 0.75 (95% CI 0.62-0.90)). However, mortality increased in obese class III (HR 1.36 (95% CI 1.00-1.86)). Death was primarily attributable to cardiovascular causes. Within a large, multinational cohort with moderate COPD and increased cardiovascular risk, the phenomenon of reduced mortality with obesity did not persist at BMI >40 kg·m-2, suggesting that obesity may not remain protective at the extremes in this population.

The effects of neoadjuvant chemoradiotherapy and an in-hospital exercise training programme on physical fitness and quality of life in locally advanced rectal cancer patients: a randomised controlled trial (The EMPOWER Trial).

BACKGROUND: The EMPOWER trial aimed to assess the effects of a 9-week exercise prehabilitation programme on physical fitness compared with a usual care control group. Secondary aims were to investigate the effect of (1) the exercise prehabilitation programme on psychological health; and (2) neoadjuvant chemoradiotherapy (NCRT) on physical fitness and psychological health. METHODS: Between October 2013 and December 2016, adults with locally advanced rectal cancer undergoing standardised NCRT and surgery were recruited to a multi-centre trial. Patients underwent cardiopulmonary exercise testing (CPET) and completed HRQoL questionnaires (EORTC-QLQ-C30 and EQ-5D-5L) pre-NCRT and post-NCRT (week 0/baseline). At week 0, patients were randomised to exercise prehabilitation or usual care (no intervention). CPET and HRQoL questionnaires were assessed at week 0, 3, 6 and 9, whilst semi-structured interviews were assessed at week 0 and week 9. Changes in oxygen uptake at anaerobic threshold (VO2 at AT (ml kg-1 min-1)) between groups were compared using linear mixed modelling. RESULTS: Thirty-eight patients were recruited, mean age 64 (10.4) years. Of the 38 patients, 33 were randomised: 16 to usual care and 17 to exercise prehabilitation (26 males and 7 females). Exercise prehabilitation significantly improved VO2 at AT at week 9 compared to the usual care. The change from baseline to week 9, when adjusted for baseline, between the randomised groups was + 2.9 ml kg -1 min -1; (95% CI 0.8 to 5.1), p = 0.011. CONCLUSION: A 9-week exercise prehabilitation programme significantly improved fitness following NCRT. These findings have informed the WesFit trial (NCT03509428) which is investigating the effects of community-based multimodal prehabilitation before cancer surgery. TRIAL REGISTRATION: ClinicalTrials.gov NCT01914068 . Registered 1 August 2013.

The effects of cancer therapies on physical fitness before oesophagogastric cancer surgery: a prospective, blinded, multi-centre, observational, cohort study.

Background: Neoadjuvant cancer treatment is associated with improved survival following major oesophagogastric cancer surgery. The impact of neoadjuvant chemo/chemoradiotherapy on physical fitness and operative outcomes is however unclear. This study aims to investigate the impact of neoadjuvant chemo/chemoradiotherapy on fitness and post-operative mortality. Methods: Patients with oesophagogastric cancer scheduled for chemo/chemoradiotherapy and surgery were recruited to a prospective, blinded, multi-centre, observational cohort study. Primary outcomes were changes in fitness with chemo/chemoradiotherapy, measured using cardiopulmonary exercise testing and its association with mortality one-year after surgery. Patients were followed up for re-admission at 30-days, in-hospital morbidity and quality of life (exploratory outcomes). Results: In total, 384 patients were screened, 217 met the inclusion criteria, 160 consented and 159 were included (72% male, mean age 65 years). A total of 132 patients (83%) underwent chemo/chemoradiotherapy, 109 (71%) underwent chemo/chemoradiotherapy and two exercise tests, 100 (63%) completed surgery and follow-up. A significant decline in oxygen uptake at anaerobic threshold and oxygen uptake peak was observed following chemo/chemoradiotherapy: -1.25ml.kg -1.min -1 (-1.80 to -0.69) and -3.02ml.kg -1.min -1 (-3.85 to -2.20); p<0.0001). Baseline chemo/chemoradiotherapy anaerobic threshold and peak were associated with one-year mortality (HR=0.72, 95%CI 0.59 to 0.88; p=0.001 and HR=0.85, 0.76 to 0.95; p=0.005). The change in physical fitness was not associated with one-year mortality. Conclusions: Chemo/chemoradiotherapy prior to oesophagogastric cancer surgery reduced physical fitness. Lower baseline fitness was associated with reduced overall survival at one-year. Careful consideration of fitness prior to chemo/chemoradiotherapy and surgery is urgently needed.

BACKGROUND: Cancer treatments such as chemotherapy and radiotherapy given to people with oesophageal and gastric cancer (also known as cancer of the food pipe/stomach) before surgery can improve survival. However, the impact such treatments have on fitness and recovery after surgery is unclear. The aim of this research was to understand the impact cancer treatments has on fitness and any complications after surgery. METHODS: Patients with oesophageal and gastric cancer (also known as cancer of the food pipe/stomach) who were being treated by cancer treatment and surgery were recruited from different hospitals in the UK. All participants were asked to undertake an exercise test to measure fitness and fill out questionnaires to measure quality of life before and after cancer treatment. Complications patients experienced after surgery, the number of patients who had to be readmitted to hospital 30 days after surgery and one-year survival was recorded. RESULTS: A total of 160 consented to participate in this study and 159 were included in the study (72% male, average age 65 years). In total, 132 patients (83%) had cancer treatment, 109 (71%) had cancer treatment and the two exercise tests and 100 (63%) had surgery and were followed-up after surgery. Study findings show that fitness reduced after cancer treatment. Patient's fitness levels at the start of the study (or before cancer treatment) were linked to one-year survival. The fall in fitness after cancer treatment was not linked to death at the one-year follow-up. CONCLUSION: Cancer treatments before oesophageal and gastric cancer reduce fitness. Patients with a lower fitness level before cancer treatment had a reduced overall survival at one-year. Careful consideration of fitness prior to such cancer treatments and surgery is urgently needed.

Pharmacotherapy and Lung Function Decline in Patients with Chronic Obstructive Pulmonary Disease. A Systematic Review.

Rationale: Whether pharmacological therapy alters decline in FEV1 in chronic obstructive pulmonary disease remains controversial. Because pharmacotherapy improves health status, exacerbation rate, and symptoms, it may be unethical to complete placebo-controlled long-term studies aimed at modifying FEV1 decline.Objectives: We conducted a systematic review of placebo-controlled pharmacological trials lasting ≥1 year to address the question of whether therapy alters FEV1 decline.Methods: A literature search for randomized trials that included repeated spirometry with at least one active and one placebo arm was conducted. Articles were excluded if study duration was <1 year, <3 spirometric measurements, or <100 subjects per arm. Study design was assessed using the Jadad score. To combine studies and find the estimated effect, we used random effects methodology to account for both within-study and between-study variation.Measurements and Main Results: There were 33,051 patients in the analysis (active component, n = 21,941; placebo, n = 11,110 in nine studies). The active treatment arms demonstrated a 5.0 ml/yr reduction (95% confidence interval, 0.8-9.1 ml/yr; P < 0.001) in the rate of FEV1 decline compared with the placebo arms. The relative FEV1 differences between active and placebo arms were within the range of differences reported for health status and for the exacerbation rate in the same studies.Conclusions: In chronic obstructive pulmonary disease, pharmacotherapy ameliorates rate of lung function decline. The relative benefit observed is within the range of those reported for health status and exacerbations in the same studies. Guidelines should be adjusted according to these findings.

Markers of disease activity in COPD: an 8-year mortality study in the ECLIPSE cohort.

RATIONALE: There are no validated measures of disease activity in COPD. Since "active" disease is expected to have worse outcomes (e.g. mortality), we explored potential markers of disease activity in patients enrolled in the ECLIPSE cohort in relation to 8-year all-cause mortality. METHODS: We investigated 1) how changes in relevant clinical variables over time (1 or 3 years) relate to 8-year mortality; 2) whether these variables inter-relate; and 3) if any clinical, imaging and/or biological marker measured cross-sectionally at baseline relates to any activity component. RESULTS: Results showed that 1) after 1 year, hospitalisation for COPD, exacerbation frequency, worsening of body mass index, airflow obstruction, dyspnoea and exercise (BODE) index or health status (St George's Respiratory Questionnaire (SGRQ)) and persistence of systemic inflammation were significantly associated with 8-year mortality; 2) at 3 years, the same markers, plus forced expiratory volume in 1 s (FEV1) decline and to a lesser degree computed tomography (CT) emphysema, showed association, thus qualifying as markers of disease activity; 3) changes in FEV1, inflammatory cytokines and CT emphysema were not inter-related, while the multidimensional indices (BODE and SGRQ) showed modest correlations; and 4) changes in these markers could not be predicted by any baseline cross-sectional measure. CONCLUSIONS: In COPD, 1- and 3-year changes in exacerbation frequency, systemic inflammation, BODE and SGRQ scores and FEV1 decline are independent markers of disease activity associated with 8-year all-cause mortality. These disease activity markers are generally independent and not predictable from baseline measurements.

The Multifaceted Therapeutic Role of N-Acetylcysteine (NAC) in Disorders Characterized by Oxidative Stress.

Oxidative stress, which results in the damage of diverse biological molecules, is a ubiquitous cellular process implicated in the etiology of many illnesses. The sulfhydryl-containing tripeptide glutathione (GSH), which is synthesized and maintained at high concentrations in all cells, is one of the mechanisms by which cells protect themselves from oxidative stress. N-acetylcysteine (NAC), a synthetic derivative of the endogenous amino acid L-cysteine and a precursor of GSH, has been used for several decades as a mucolytic and as an antidote to acetaminophen (paracetamol) poisoning. As a mucolytic, NAC breaks the disulfide bonds of heavily cross-linked mucins, thereby reducing mucus viscosity. In vitro, NAC has antifibrotic effects on lung fibroblasts. As an antidote to acetaminophen poisoning, NAC restores the hepatic GSH pool depleted in the drug detoxification process. More recently, improved knowledge of the mechanisms by which NAC acts has expanded its clinical applications. In particular, the discovery that NAC can modulate the homeostasis of glutamate has prompted studies of NAC in neuropsychiatric diseases characterized by impaired glutamate homeostasis. This narrative review provides an overview of the most relevant and recent evidence on the clinical application of NAC, with a focus on respiratory diseases, acetaminophen poisoning, disorders of the central nervous system (chronic neuropathic pain, depression, schizophrenia, bipolar disorder, and addiction), cardiovascular disease, contrast-induced nephropathy, and ophthalmology (retinitis pigmentosa).