Clinical and laboratory correlations in patients with cystic fibrosis and Pseudomonas aeruginosa infection: The experience of a regional centre.

Pseudomonas aeruginosa (Pa) is the most important pathogen affecting the prognosis of patients with cystic fibrosis (CF). Distinguishing the correlations associated with PA infection may change the way in which investigation and therapeutic plans are approached. This study aims to evaluate the correlations between various factors such as age at diagnosis, nutritional status, homozygous status of delF508 mutation, the number of exacerbations per year, imagistic modifications, the presence of chronic infection with Staphylococcus aureus, serum levels of total immunoglobulins G (IgG) and gammaglobulins and ventilation parameters - forced vital capacity (FVC) and one-second forced expired volume (FEV1) and their association with Pa infection.

Methods: The associations between the analyzed parameters have been made by logistic regression; the comparisons between means of continuous variables were performed using Studen t-test; the variables distribution was tested using chi-square-test; and correlations between variables were assessed using Pearson coefficient.

Results: The mean age at the acquisition of Pa was 5.26 (±5.3 years). Of the 50 patients included in the study, 21 acquired the Pa infection having the median age of primo-infection of 3 years. The study identified a greater number of exacerbations per year in those infected with Pa (2.71 compared to 1.38 exacerbations per year; p=0.002); the increase of radiological score with 1 unit associated with an increased risk of infection with Pa (OR 1.31; 95% CI 1.10-1.56;p=0.002), the mean Brasfield radiologic score is lower for uninfected children (6.9 vs. 11 points, p=0.001); increasing the degree of bronchiectasis associated with Pa infection (OR 3.75;CI 1.77-7.96;p=0.001); gammaglobulin (15.91 vs. 19.42%;p=0.01) or immunoglobulin G values (IgG) (9.8 vs. 11.9 g/L;p=0.05) were higher for those infected.

Conclusions: The increased number of exacerbations per year, the severity of imagistic modifications, and IgG and gammaglobulin values are associated with Pa infection. Tracking these parameters guides the therapeutic conduct.