Precision medicine is a patient-specific approach that integrates all relevant clinical, genetic and biological information in order to optimise the therapeutic benefit relative to the possibility of side-effects for each individual. Recent clinical trials have shown that higher blood eosinophil counts are associated with a greater efficacy of inhaled corticosteroids (ICSs) in chronic obstructive pulmonary disease (COPD) patients. Blood eosinophil counts are a biomarker with potential to be used in clinical practice, to help target ICS treatment with more precision in COPD patients with a history of exacerbations despite appropriate bronchodilator treatment.The Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2017 pharmacological treatment algorithms, based on the ABCD assessment, can be applied relatively easily to treatment-naive individuals at initial presentation. However, their use is more problematic during follow-up in patients who are already on maintenance treatment. There is a need for a different system to guide COPD pharmacological management during follow-up.Recent large randomised controlled trials have provided important new information concerning the therapeutic effects of ICSs and long-acting bronchodilators on exacerbations. The new evidence regarding blood eosinophils and inhaled treatments, and the need to distinguish between initial and follow-up pharmacological management, led to changes in the GOLD pharmacological treatment recommendations. This article explains the evidence and rationale for the GOLD 2019 pharmacological treatment recommendations.

IMPORTANCE Outcomes after exacerbations of chronic obstructive pulmonary disease (COPD) requiring acute noninvasive ventilation (NIV) are poor and there are few treatments to prevent hospital readmission and death.OBJECTIVE To investigate the effect of home NIV plus oxygen on time to readmission or death in patients with persistent hypercapnia after an acute COPD exacerbation.

This document provides clinical recommendations for treatment of chronic obstructive pulmonary disease (COPD) exacerbations.Comprehensive evidence syntheses, including meta-analyses, were performed to summarise all available evidence relevant to the Task Force's questions. The evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluation approach and the results were summarised in evidence profiles. The evidence syntheses were discussed and recommendations formulated by a multidisciplinary Task Force of COPD experts.After considering the balance of desirable and undesirable consequences, quality of evidence, feasibility, and acceptability of various interventions, the Task Force made: 1) a strong recommendation for noninvasive mechanical ventilation of patients with acute or acute-on-chronic respiratory failure; 2) conditional recommendations for oral corticosteroids in outpatients, oral rather than intravenous corticosteroids in hospitalised patients, antibiotic therapy, home-based management, and the initiation of pulmonary rehabilitation within 3 weeks after hospital discharge; and 3) a conditional recommendation against the initiation of pulmonary rehabilitation during hospitalisation.The Task Force provided recommendations related to corticosteroid therapy, antibiotic therapy, noninvasive mechanical ventilation, home-based management, and early pulmonary rehabilitation in patients having a COPD exacerbation. These recommendations should be reconsidered as new evidence becomes available.

C hronic obstructive pulmonary disease (COPD) is the third leading cause of death worldwide; COPD led to 3.2 million deaths in 2017, a toll expected to reach 4.4 million yearly by 2040. 1,2 With a worldwide prevalence of 10.1%, COPD afflicts many people in low-income, middle-income, and wealthy countries (Fig. 1), and years of life lost prematurely increased 13.2% between 2007 and 2017. 1 Although COPD has traditionally been considered a disease that affects men, in some countries, the prevalence and associated mortality are higher among women than among men. In this review, we update the clinical face of COPD, concentrating on the pulmonary aspects of the disease, which also affects many other organ systems. The pathogenesis of COPD is discussed in a companion article by Agustí and Hogg in this issue of the Journal, 3 and the review of muco-obstructive lung diseases in a recent issue of the Journal 4 complements this article. DefinitionCOPD is an umbrella term for various clinical entities with multiple causes resulting in airflow limitation that is not fully reversible. 3,5-7 Hence, COPD is better defined as a clinical syndrome characterized by chronic respiratory symptoms, structural pulmonary abnormalities (airways disease, emphysema, or both), lungfunction impairment (primarily airflow limitation that is poorly reversible), or any combination of these. 8 Patients with COPD are at a higher risk than patients without COPD for the development of coexisting conditions that are associated with poor outcomes, including death. 9,10 Ta xonom yAs described in the companion article on the pathogenesis of COPD, a period of environment-gene interaction precedes spirometric airflow limitation. 3 In persons without obstruction who are exposed to cigarette smoking, 3,4 the presence of cough, sputum, and dyspnea and the detection of a low diffusing capacity of the lung for carbon monoxide (DLco) are associated with an increase in the risk of COPD. [11][12][13] Similarly, in persons without obstruction who have a baseline value for forced expiratory volume in 1 second (FEV 1 ) at the low end of the normal range, a reduction in FEV 1 that exceeds 40 ml per year (normal rate of loss after the third decade of life, <25 ml per year) over an 18-month period is associated with an increase by a factor of 36 in the risk that COPD will develop in the next 5 years. 14 Patients in this "silent" stage constitute a group that can be labeled as having "pre-COPD," with the term "COPD" reserved for patients with spirometric airflow