A75-02 Clinically Significant Respiratory Exacerbations in Smokers Without Chronic Obstructive Pulmonary Disease (COPD): Findings From a US Veterans Lung Cancer Screening

Background

People with smoking history but without spirometric COPD, also described as tobacco-exposed persons with preserved spirometry (TEPS), are increasingly recognized to experience respiratory exacerbations with acutely worsening dyspnea, cough, and mucus production, symptoms similar to “exacerbation” episodes experienced by people with COPD. Whether TEPS experience clinically significant respiratory exacerbations, and whether the frequency and severity of these events differ from those observed in COPD, remains understudied, particularly among real-world patient population.

Objective

To examine the frequency and severity of respiratory exacerbations among TEPS.

Methods

We recruited current and former (defined by abstinence for ≥1 year) smoking patients from a lung cancer screening cohort at the San Francisco VA Health Care System. Patients were classified as having spirometric COPD or TEPS by GOLD guidelines-patients with preserved ratio and impaired spirometry (PRISm) were excluded. The frequency and severity of respiratory exacerbations occurring over the preceding three years prior to enrollment were assessed using a questionnaire that elicited standardized criteria for exacerbation diagnosis based on acute worsening of respiratory symptoms and requiring treatment. For patients with COPD, events were classified as acute exacerbations of COPD; for TEPS, identical criteria were applied but events were classified as respiratory exacerbations. Exacerbations were categorized by severity from mild to severe, with moderate-to-severe events as the primary outcome. Exacerbation outcomes were analyzed using regression modeling with TEPS vs. COPD status as the primary predictor with adjustment for covariates.

Results

The cohort included 206 patients with TEPS and 295 with spirometric COPD (GOLD 1=35.2%; GOLD 2=51.2%; GOLD 3=10.2%; GOLD 4=3.4%) (Table). Over the three years prior to enrollment, 8% of TEPS reported at least one moderate-to-severe (m/s)-exacerbation, compared with 26% of those with COPD. When assessed on an annual basis, 5% of TEPS experienced ≥1 m/s-exacerbations per year, compared with 13% among those with COPD. In regression analyses, those with COPD were more likely to experience at least one m/s-exacerbation per year (OR = 2.97±1.45, p < 0.01) and more likely to experience more than two m/s-exacerbations per year (OR = 10.54±2.12, p < 0.01) (Table). Although the overall total number of m/s-exacerbations was higher in COPD patients compared to TEPS patients (ß=0.85±2.60, p < 0.01), the number of m/s-exacerbations did not differ significantly between COPD and TEPS when analysis was restricted to individuals with at least one event (ß=0.39±0.26, p = 0.14).

Conclusions

Among Veterans with a smoking history, those with preserved spirometry experienced clinically significant respiratory exacerbations, including events requiring medical intervention or hospitalization, although at lower frequency than those with COPD.

This abstract is funded by: The Flight Attendant Medical Research Institute