Mild chronic obstructive pulmonary disease: why spirometry is not sufficient!

ABSTRACT

Introduction: Chronic obstructive pulmonary disease (COPD) – an inflammatory disease of the airways, alveoli and lung microvasculature – is a leading cause of death worldwide. Smokers with milder airway obstruction constitute the majority of patients with this disease. Many studies have shown increased morbidity, activity-related dyspnea, exercise intolerance and mortality in such patients, compared with age-matched healthy populations. Clinical evaluation of symptomatic smokers with ostensibly mild airway obstruction poses a challenge in clinical practice as spirometry can obscure extensive heterogeneous pathophysiological impairment.

Areas covered: A detailed review of the evidence for complex biological, physiological and radiological abnormalities in smokers who barely fit arbitrary spirometric criteria for COPD diagnosis. A brief discussion of the debate about current diagnostic spirometric criteria for COPD that can lead to diagnostic confusion and, in-some-instances, to inappropriate management. Finally, we provide a review of the clinical implications of these structural and functional abnormalities and try to build a solid rationale for earlier detection and effective, timely management.

Expert commentary: The prevalence of mild COPD among smokers is high, yet under-diagnosis remains a major problem and there is lack of evidence-based management recommendations for this sub-population. Further tests beyond spirometry are useful in uncovering patho-physiological derangements that are clinically relevant.

KEYWORDS:

• Mild COPD
• spirometry
• imaging
• small airway remodeling
• vascular injury
• exercise
• dyspnea

Declaration of interest

Financial support was provided through the John Alexander Stewart scholar award from Queen’s University to AF. Elbehairy. Outside the submitted work, D. O’Donnell has received research funding via Queen’s University from AstraZeneca, Boehringer Ingelheim and GlaxoSmithKline; and has served on speakers bureaus, consultation panels and advisory boards for AstraZeneca, Boehringer Ingelheim and GlaxoSmithKline. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Additional information

Funding

This paper was not funded.