TOPLINE

Patients with asthma who had persistent airflow limitation (PAL) experienced severe exacerbations more than twice as often as those without PAL and faced a nearly twofold higher annual incidence of these events. The risk escalated with increasing severity of airflow obstruction, with the most advanced stage showing more than triple the risk compared with patients without PAL.

METHODOLOGY

• A multicenter cohort study combined retrospective data from two tertiary hospitals in South Korea (January 2013–December 2019) with data from a prospective cohort (April 2018–August 2023), enrolling a total of 849 adult patients with physician-diagnosed asthma.
• PAL was defined as postbronchodilator forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio < 0.70 at baseline spirometry; severity was graded using the STaging of Airflow obstruction by Ratio classification (STAR stage), ranging from stage 0 (no PAL) to stage 4 (FEV1/FVC < 0.40).
• Primary outcomes included the annual incidence of subsequent moderate-to-severe acute exacerbations and time-to-first severe exacerbation; secondary outcomes assessed longitudinal lung function decline through repeated spirometric measurements over a mean follow-up of approximately 4 years.

TAKEAWAY

• Overall, 75.4% of patients had PAL at baseline; during follow-up, PAL was associated with a significantly higher incidence of severe exacerbations (13.0% vs 5.7%; P = .046) and a 1.77-fold higher annual incidence rate (P = .014).
• The risk for severe exacerbations was approximately 1.8-fold, 1.7-fold, and 2.3-fold higher with STAR stage 1, 2, and 4 PAL compared with stage 0 PAL.
• In time-to-event analysis, STAR stage 4 was associated with a more than threefold higher risk for severe exacerbations compared with stage 0 (adjusted hazard ratio [HR], 3.32; 95% CI, 1.60-6.89).
• Annual FEV1 decline was slower in the PAL group than in the non-PAL group (−28.1 mL/year vs −42.5 mL/year; P = .028), but within patients with PAL, STAR stage 4 demonstrated the most pronounced declines in both FEV1 and FVC, likely reflecting higher smoking intensity and more frequent severe exacerbations in this subgroup.

IN PRACTICE

"The presence and severity of PAL convey important prognostic information beyond cross-sectional lung function, underscoring its role as a longitudinal risk phenotype. Assessing PAL and its severity may therefore aid risk stratification and prognostication in clinical practice," wrote the authors of the study.

SOURCE

The study was led by Jung-Kyu Lee, Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, South Korea. It was published online on July 9 in Journal of Asthma and Allergy.

LIMITATIONS

The study combined retrospective and prospective cohorts with differing enrollment criteria and data collection methods. Recruitment from tertiary referral hospitals may limit generalizability to the broader asthma population. The observational design precludes definitive causal inferences.

DISCLOSURES

No funding was reported for this study. The authors reported no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.