The American College of Physicians (ACP), American College of Chest Physicians (ACCP), American Thoracic Society (ATS), and European Respiratory Society (ERS) released a joint clinical practice guideline on diagnosing and treating stable chronic obstructive pulmonary disease (COPD) in Annals of Internal Medicine. The guideline addresses COPD treatment standards from diagnosis and management to prevention and treatment of exacerbations. Physicians aim to assist their patients in quitting smoking, as COPD occurs primarily in cigarette smokers.