They presented with a more severe respiratory impairment, with a lower mean FEV(1) (29% of predictive value vs 58% of predictive value, p < 0.001); a higher Pseudomonas colonization rate (97% vs 57%, p < 0.01); a more frequent end-stage respiratory insufficiency, defined by a FEV(1) < 30% (73% vs 29%, p < 0.05); and a more marked yearly decline of FEV(1) (3% vs 1.4%, p < 0.001).