Relying on spirometry to assess smoking-induced lung disease is inadequate, say researchers
Relying on spirometry to assess smoking-induced lung disease is inadequate, say researchers, and fails to identify a large group of people with considerable respiratory impairment
Around 50% of current or former smokers with preserved pulmonary function on spirometry suffered from chronic respiratory symptoms, the study of 2700 people found.
These individuals were more likely to have respiratory exacerbations, greater limitation of activity, and imaging evidence of lung pathology than asymptomatic former or current smokers or a control group.
And despite falling short of a diagnosis of COPD, 42% and 23% of this group used bronchodilators and inhaled glucocorticoids, respectively, a practice without an evidence base, the authors said.
Therefore the current use of spirometry to diagnose COPD “may not adequately cover the breadth of symptomatic smoking-related lung disease,” they concluded.
According to an accompanying editorial, the research introduced “a paradigm shift in our approach to smoking-induced disease” whereby smoking itself should be considered the disease.
Defining COPD in terms of airflow limitation alone had limitations for clinical practice, because it ignored symptoms and those with preserved spirometric findings, it said.
“Now we know that symptoms can be at least as sensitive, and certainly more useful, in identifying patients who need early intervention,” he said. “This finding clearly suggests that the FEV1 is not sensitive in a large majority of smokers and may be just one of the tools needed to make an early diagnosis in a subgroup of smokers.”
NEJM 2016; online 12 May
