“Mild” Chronic Obstructive Pulmonary Disease—Is there a Case for Earlier Treatment?

O’Donnell D, Raghavan N, Ora J, Webb K. “Mild” COPD – Is there a case for earlier treatment? Annals of Respiratory Medicine, February 2010; 1(1):23-30

Review Article

Natya Raghavan ^{1 2}, Josuel Ora ¹, A Katherine Webb ¹ and E Denis O’Donnell ¹
Affiliations: 1Respiratory Investigation Unit, Department of Medicine, Queen’s University and Kingston General Hospital, Kingston, Ontario, Canada and 2Division of Respirology, McMaster University, Hamilton, Ontario, Canada


ABSTRACT

The majority of smokers who suffer from chronic obstructive pulmonary disease (COPD) have milder airway obstruction, as measured by standard spirometry. Relatively few studies have been conducted in mild COPD and, beyond the imperative of smoking cessation, no evidence‐based guidelines for management currently exist. More detailed physiological testing of patients with mild COPD can uncover heterogeneous peripheral airway dysfunction, as manifest by increased airway closure, abnormal distribution of ventilation, and disrupted pulmonary gas exchange. These physiological derangements are further amplified during physical exertion, and can give rise to increased respiratory discomfort and earlier exercise cessation. The clinical consequences of respiratory impairment in milder COPD are variable, but population studies have confirmed an association with increased morbidity, healthcare utilization, and even mortality. The presence of respiratory symptoms in patients with mild COPD and, in particular, self‐reported exertional breathlessness appears to portend more negative clinical outcomes. The rationale for targeted screening (by spirometry) of symptomatic smokers to expedite diagnosis is firmly established but, unfortunately, underdiagnosis of this condition remains a pervasive problem worldwide. In this paper, we review what is currently known about the pathophysiology and clinical consequences of mild COPD in order to provide a foundation for the development of an effective management paradigm.

Keywords: chronic obstructive pulmonary disease (COPD), small airway dysfunction, dyspnea, bronchodilators, lung hyperinflation
Correspondence: Denis E O’Donnell, Department of Medicine, Division of Respirology, Queen’s University, 102 Stuart Street, Kingston, Ontario, Canada, K7L 2V6. e‐mail: odonnell@queensu.ca