Interstitial lung abnormalities linked to COPD exacerbations
Patients with chronic obstructive pulmonary disease who also had certain interstitial lung abnormalities experienced more exacerbations and reduced lung function than those without such abnormalities, findings from a retrospective study has shown.
Interstitial lung abnormalities (ILA) are considered precursor lesions of interstitial lung disease and previous studies suggested an association with poor outcomes among chronic obstructive pulmonary disease (COPD) patients, but data on long-term clinical relevance are limited, wrote Tae Seung Lee, MD, of Seoul (South Korea) National University Hospital, and colleagues.
In a study published in Chest, the researchers reviewed data from 363 COPD patients including 44 with equivocal ILA and 103 with definite ILA. Overall, the ILA patients were older and had poorer lung function than non-ILA patients. Patients received chest CT scan and longitudinal pulmonary function tests between January 2013 and December 2018.
Over an average follow-up period of 5.4 years, patients with ILA experienced significantly more acute COPD exacerbations than did those without ILA (adjusted odds ratio, 2.03). The percentages of frequent exacerbators among patients with no ILA, equivocal ILA, and definite ILA were 8.3%, 15.9%, and 20.4%, respectively.
“Acute exacerbation is an important event during the clinical course of COPD, because it is associated with temporary or persistent reductions in lung function, lower quality of life, hospitalization, and mortality,” the researchers noted.
In a multivariate analysis, the annual decline in lung function (FEV1) was –35.7 in patients with equivocal ILA, compared with –28.0 in patients with no ILA and –15.9 in those with definite ILA.
“This may be due to the distribution of the spirometric stages in each group, and to the resulting changes in lung function,” the researchers wrote. In this study, “the equivocal ILA group had a significantly lower baseline FEV1 than the other groups. In our study population, the lower the spirometric stage, the faster the annual decline in FEV1, consistent with the results of a prior prospective study of a COPD cohort.”
The findings were limited by several factors including the retrospective design and relatively small number of ILA patients, as well as the limited evaluation of ILA and potential for selection bias, the researchers noted. However, the result support the impact of ILA on exacerbations and accelerated decline in lung function in COPD patients.
The study received no outside funding. The researchers had no financial conflicts to disclose.
SOURCE: Lee TS et al. Chest. 2020 Aug 13. doi: 10.1016/j.chest.2020.08.017.
