Clinical outcomes
Of 202 APEs in 51 patients, 109 had cultures positive for P. aeruginosa and were included in the clinical analysis, 74 and 35 in the positive and negative outcome groups, respectively. The average Matouk score was 46.5 and 40.8 in the positive and negative outcome group, respectively. Table 1 shows patient’s characteristics and Table 2 shows APE-specific data. The negative outcome group was composed of 31 (88.6%) APEs with 1 criterion and 4 (11.4%) APEs with 2 criteria. Early APE reoccurrence was the leading criteria of treatment failure (71.4%) while antibiotic change was present in 40% of failures.
Of the 109 P. aeruginosa positive cultures, 97 were sensitive to at least one antibiotic administered while 12 were resistant to all antibiotics administered. A total of 65 (65.0%) susceptible strains and 6 (50%) resistant strains were in the positive outcome group.
Between outcome groups, only APE occurrence per patient, baseline ppFEV1 and concomitant antibiotics significantly differed. APE occurrence per patients, severity, concomitant antibiotics and microorganism-specific data were included in the multivariable analysis. Baseline ppFEV1 was excluded as to avoid confusion bias. The interaction between concomitant antibiotic and severity of the APE was not significant (p =0.695).
In relation to treatment outcome, APE occurrence per patients (p =0.004), ceftazidime and piperacillin/tazobactam as concomitant antibiotics (p <0.001 and p =0.047, respectively) were the only variables achieving significance (Table 3).
Of the 153 evaluated APEs, no cases of nephrotoxicity were identified. Nephrotoxicity could not be evaluated in 51 APEs as a result of missing data; 28 in the analyzed group, 15 (24.2%) and 13 (27.7%) APEs in the positive and negative outcome groups, respectively.