Study Explores Persons With Tobacco Exposure, Preserved Spirometry

Persons with tobacco exposure and preserved spirometry (TEPS) with symptoms (symptomatic TEPS) do not have accelerated rates of decline in forced expiratory volume in one second (FEV₁) or chronic obstructive pulmonary disease (COPD) versus those with asymptomatic TEPS, but they do have more respiratory exacerbations, according to a study published in the Aug. 1 issue of the Journal of the American Medical Association.

William McKleroy, M.D., from the University of California in San Francisco, and colleagues defined the natural history of symptomatic TEPS in an extension of the SPIROMICS I multicenter study of persons aged 40 to 80 years who smoked cigarettes, with or without COPD, and controls without tobacco exposure or airflow obstruction. Data were included for 1,397 study participants: 226 with symptomatic TEPs and 269 with asymptomatic TEPS.

The researchers found that at a median follow-up of 5.76 years, the decline in FEV₁ was −31.3 and −38.8 mL/y for participants with symptomatic and asymptomatic TEPS, respectively. The cumulative incidence of COPD was 33.0 and 31.6 percent for those with symptomatic and asymptomatic TEPS, respectively. Significantly more respiratory exacerbations were seen for participants with symptomatic versus asymptomatic TEPS (0.23 versus 0.08 exacerbations per person-year; rate ratio, 2.38).