Figure 2. Age dependent change in FEV1 by exacerbation rate in males and females.

There was no significant main effect or interaction with age on female relationship of exacerbation rate with FEV1 (panel A). Male subjects (panel B) demonstrated a significantly lower FEV1 with increasing age associated with recurrent exacerbations in prior year and an additive effect if there were ≥3 exacerbations in the year before that. Solid line, no exacerbations in the past year; dashed line ≥3 exacerbations in the past year, none in the year prior; dotted line, ≥3 exacerbations in the past year, ≥3 exacerbations in the year prior.