Abnormal spirometry has been detected in a sample of patients with more than 10 pack-years of smoking but without a current COPD diagnosis
Abnormal spirometry, defined as either airflow obstruction (AFO) or preserved ratio impaired spirometry, has been identified in just over a third of patients deemed at high risk of developing COPD because of a smoking history of at least 10 pack-years according to an analysis of data from the COPDgene study.
Chronic obstructive pulmonary disease (COPD) is an increasingly important cause of morbidity, disability, and mortality worldwide with data from 2019, estimating that globally, 391·9 million people aged 30-79 years had COPD. Nevertheless, COPD often goes undetected and one study of the general population, revealed how of 95,288 screened individuals, 3699 (11%) met the COPD criteria yet 2903 (78%) of these were undiagnosed yet 71% were symptomatic. However, the prevalence of undiagnosed COPD among heavy smokers, i.e., those who are at a high risk of developing the disease is less clear and was the overall objective of the current study, where researchers assessed the extent of abnormal spirometry, based on AFO and preserved ratio impaired spirometry, among a cohort of heavy smokers.
The team included individuals with a ≥10 pack-years of smoking and for whom there was no self-reported or physician diagnosed COPD, asthma or other related disease. In addition, a subgroup of patients were followed-up for a period of 5 years.
Abnormal spirometry findings
A total of 5,055 individuals without known obstructive lung disease were enrolled in the study, ranging in age from 56 to 61. Abnormal spirometry, based on AFO and preserved ratio impaired spirometry was seen in 21 % and in 13.6% of participants respectively.
Factors such as age, pack-years, current smoking and a history of acute bronchitis were all significantly and positively associated with AFO. In contrast, body mass index, female gender and Black ethnicity, were inversely, but significantly associated with AFO.
In a subgroup of 2,800 participants who had 5 years of follow-up, 19% had an incident diagnosis of COPD and factors significantly associated with the diagnosis included a MMRC > 2 (dyspnoea score) and the presence of a chronic, productive cough.
The authors concluded that there was a high prevalence of undiagnosed COPD in at-risk individuals and that the associated factors could be used to identify those at risk for enable earlier diagnosis and treatment of the disease.
Trab TV et al. Prevalence of abnormal spirometry in individuals with a smoking history and no known obstructive lung disease. Respir Med 2023