THE AGE AT ONSET OF CHRONIC PSEUDOMONAS-AERUGINOSA COLONIZATION IN CYSTIC-FIBROSIS - PROGNOSTIC-SIGNIFICANCE

To evaluate the prognostic significance of the age at onset of chronic Pseudomonas aeruginosa colonization (OPCP) with respect to pulmonary disease progression in patients with cystic fibrosis (CF), a retrospec tive long-term analysis using annual chest radiographs was performed o n 54 CF patients. Thirty-seven patients (68%) were chronically coloniz ed before the age of 12 years (group 1), 17 patients (32%) thereafter (group 2). These two groups did not significantly differ in terms of m ean duration of follow up (16.2 +/- 5.9 years), sex, CF genotypes, col onization with other respiratory pathogens, supportive medical treatme nt and death rate during the study period. Chest radiographs were eval uated according to the Chrispin-Norman score, increasing scores repres enting increasing severity of respiratory disease. Ln both groups, pro gression of score means was not accelerated up to 6 years after OCPC ( Scores at OCPC set 0; mean score +/- SEM 6 years prior to OCPC - 5.6 /- 2.0; 10 years after OCPC + 3.6 +/- 0.7 points). Patients chronicall y colonized prior to age 12 years (group 1) scored significantly highe r between age 2 and 11 years (maximum difference at age 8 years [mean +/- SEM]: 9.4 +/- 0.7 vs. 4.3 +/- 1.3 points; P = 0.002) as compared t o group 2. After age ii years, mean scores were similar in both groups , since in group 2 scores increased rapidly after age s years. We conc lude that OCPC did not cause an immediate acceleration of CF lung dise ase judged by serial chest radiographs. Rapid progression in group 2 ( OCPC after age 12 years) was independent of OCPC since it occurred ear lier. These data indicate that OCPC may be a marker rather than the ca use of respiratory disease progression.