Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. C URRENT O PINION Chronic obstructive pulmonary disease comorbidities Jeanette P. Brown and Carlos H. Martinez Purpose of review Classic descriptions of chronic obstructive pulmonary disease (COPD) centered on its impact on respiratory function. It is currently recognized that comorbidities contribute to the severity of symptoms and COPD progression. Understanding COPD-comorbidities associations could provide innovative treatment strategies and identify new mechanistic pathways to be targeted. Recent findings Some comorbidities are clustered with specific COPD phenotypes. There are stronger associations between airway-predominant disease and cardio-metabolic comorbidities, whereas in emphysema-predominant COPD sarcopenia and osteoporosis are frequent. These patterns suggest different inflammatory pathways acting by COPD phenotype. Osteoporosis is a major concern in COPD, particularly among men. Although b-blockers use for cardiac indications in COPD remains low, recent evidence suggests that this medication group could decrease COPD exacerbations. Gastroesophageal reflux is consistently associated with poor COPD outcomes, but mechanisms and impact of treatment are still unclear. Nontraditional comorbid conditions, such as cognitive impairment, anxiety, and depression have significant impact in COPD outcomes. Summary Clinicians should screen their COPD patients for the presence of cardiovascular disease, diabetes, osteoporosis, sleep apnea, and sarcopenia, comorbidities for which specific treatments are available and associated with better COPD outcomes. The impact of interventions to treat gastroesophageal reflux disease, anxiety and depression is still to be defined. Keywords aging, cardiovascular disease, chronic obstructive pulmonary disease, comorbidities, multimorbidity INTRODUCTION The definition of chronic obstructive pulmonary disease (COPD) used by the Global Initiative for Obstructive Lung Disease [1] is notoriously more comprehensive that previous efforts, describing the disease not just by its physiologic (airflow limita- tion) and pathophysiologic characteristics (an enhanced chronic inflammatory response in the airways and lungs to noxious particles or gases); it also emphasizes that COPD is preventable and treat- able, and underscores the role of exacerbations and comorbidities as contributors to the overall severity in individual patients. Clinicians are familiar with the fact that their COPD patients have multiple coexistent diseases. There are shared risk factors between COPD and other diseases (tobacco use, socioeconomic status, low lung function, and occupational exposures); COPD is more frequent in the elderly population, and the aging process includes accruing more diseases and limitations [2]; and there is growing evidence that inflammatory phenomena in one organ (e.g., the lung) could spill to the systemic circulation and affect other systems [3]. However, beyond the simple co-occurrence of two diseases, recent research efforts have proved that there are unique interactions between COPD and certain specific chronic conditions. Some diseases could influence COPD outcomes (disease progression and exacerbation frequency), including higher costs Division of Pulmonary and Critical Care Medicine, University of Michigan Health System, Ann Arbor, Michigan, USA Correspondence to Carlos H. Martinez, MD, MPH, Division of Pulmonary and Critical Care Medicine, University of Michigan Medical Center, 3916 Taubman Center, SPC 5360, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0360, USA. Tel: +1 734 763 2540; fax: +1 734 936 5048; e-mail: carlosma@med.umich.edu Curr Opin Pulm Med 2016, 22:113–118 DOI:10.1097/MCP.0000000000000241 1070-5287 Copyright ß 2016 Wolters Kluwer Health, Inc. All rights reserved. www.co-pulmonarymedicine.com REVIEW