Individuals with pre-bronchodilator airflow obstruction at significant risk for COPD

Individuals with pre-bronchodilator airflow obstruction appeared to be at significant risk for future COPD development, researchers reported in the American Journal of Respiratory and Critical Care Medicine.

“One obvious question is whether individuals with [variable obstruction] actually have pre-COPD with early airway pathophysiologic changes and whether these changes eventually progress to fixed obstruction, with post-[bronchodilator] FEV₁/FVC < 0.7,” Russell G. Buhr, MD, PhD, assistant professor in the division of pulmonary and critical care medicine at David Geffen School of Medicine at UCLA and of the Center for the Study of Healthcare Innovation, Implementation and Policy at the Greater Los Angeles Veterans Affairs Healthcare System, Los Angeles, and colleagues wrote. “We sought to investigate individuals with variable obstruction using the SPIROMICS cohort of extensively characterized patients with COPD of varying severity as well as people with current or former tobacco exposure with preserved spirometry and nonsmoking controls.”

Researchers assessed data from the SPIROMICS — or the Subpopulations and Intermediate Outcome Measures in COPD study — cohort of 175 patients (mean age, 63.2 years; 56% men) with COPD and with prebronchodilator variable obstruction and 603 control individuals (mean age, 60.7 years; 44% men) without airflow obstruction.

Researchers evaluated differences in baseline radiographic emphysema and small airways disease and change in lung function, functional capacity, health status, exacerbation rates and COPD progression between the two groups.

Participants with variable obstruction had 6.2 times (95% CI, 4.6-8.3) the risk for future COPD development when controlling for other factors. In fact, 61% of those with variable obstruction at baseline progressed to COPD during the study compared with 14% of those without variable obstruction (P < .001).

Participants with variable obstruction also had significantly lower baseline pre-bronchodilator FEV₁ by 9.61% (95% CI, –11.79% to –7.43%), lower post-bronchodilator FEV₁ by 6.6% (95% CI, –8.73% to –4.48%) and greater post-bronchodilator FEV₁ decline over time by 0.61% (95% CI, –0.99% to –0.23%) annually compared with participants without variable obstruction.

Further, patients with vs. without variable obstruction experienced greater rates of pre-bronchodilator FVC decline, measured at –28 mL/year (P < .001), and post-bronchodilator FVC decline, measured at –16 mL/year (P = .017).

Researchers observed no significant differences in COPD exacerbations between the groups.

“Prospective studies to assess the long-term changes in disease trajectory by early intervention with COPD therapies and smoking cessation assistance among those with this phenotype, as well as the health status and economic tradeoffs thereof, are needed to understand the utility of changes to clinical practice,” the researchers wrote.