Candida Colonization of the Respiratory Tract and Subsequent Pseudomonas Ventilator-Associated Pneumonia: Statistical Analysis

Candida Colonization of the Respiratory Tract and Subsequent Pseudomonas Ventilator-Associated Pneumonia: Statistical AnalysisThe increase in the risk of VAP was assessed by conditional logistic regression analysis for 1:n matching, using the SAS procedure (PHREG, Version 8.02; SAS Institute) in a nested exposed-unexposed design. An exposed patient was a patient free from VAP at Candida colonization time. An unexposed patient was a patient with VAP before colonization time or without Candida colonization. In the exposed patients, only VAP cases occurring at least two days after the onset of bronchial Candida colonization were considered. Similar exposed unexposed selections were performed using P aeruginosa VAP and Staphylococcus aureus VAP as events of interest. Patients were considered between MV onset and occurrence of VAP, ICU discharge, or death. birth control pills

We calculated crude odds ratio (OR) and OR adjusted on matching criteria and variables unbalanced between exposed and unexposed patients. Analyses were adjusted on patient characteristics (direct admission, age, sex, SAPS II, LOD, presence or absence of any chronic illness [binary variable], infection or acute lung injury at ICU admission, use of vasopressors, hemodialysis or hemofiltration, sucralfate, antimicrobials agents including antifungal agents).
Results were expressed as OR and 95% confidence interval (CI). All statistical tests were two tailed, and p < 5% was considered significant. All statistical analysis was performed using statistical software (version 8.02; SAS Institute).
During the 4-year study period, 803 immunocompetent patients received MV for > 2 days in the six study ICUs. Among them, 214 patients (26.6%) had respiratory tract Candida colonization. Patient characteristics are reported in Table 1, and the patient flowchart is shown in Figure 1. Thirty patients had colonization before MV onset. The Candida colonization rate was 19.54% (16.48-22.60) on day 5, 31.49% (27.10-35.88) on day 15, and 33.66% (28.76-38.56) on day 30. C albicans was the main species (67.7%), followed by Candida glabrata (20%) and Candida tropicalis (13%). Each of these three species was usually the only pathogen retrieved from the respiratory tract, whereas Candida krusei, Candida parapsilosis, and Candida lusitaniae were generally found in combination with another Candida species.

Table 1—Patient Characteristics

Characteristics Respiratory Tract Candida Colonization (n = 214) No Respiratory Tract Candida Colonization (n = 589) p Valuef
Patient age, yr
< 54 52 (24.3) 213 (36.2) 0.002
54 to 77 116 (54.2) 294 (49.9) 0.3
> 77 46 (21.5) 82 (19.9) 0.01
Diabetes mellitus 10 (4.7) 14 (2.4) 0.1
Reasons for ICU admission
Acute respiratory failure 71 (33.2) 129 (21.9) 0.0011
Shock 55 (25.7) 142 (24.1) 0.6
Coma 33 (15.4) 199 (33.8) < 0.0001
Infection at admission 114 (53.3) 204 (34.6) < 0.0001
Direct admission 80 (37.4) 334 (46.7) < 0.0001
SAPS II score at admission (range) 45 (33-60) 47 (36-61) 0.2
LOD score at admission (range) 5 (3-7) 6(3-8) 0.038
Acute lung injury at admission! 150 (71.1) 365 (63.5) 0.047
ARDS at admission§ 89 (42.2) 222 (38.6) 0.44
Need for vasopressors 144 (67.3) 340 (57.7) 0.014
Antibiotics within 3 d after ICU admission 176 (82.2) 429 (72.8) 0.0062
Type of antibiotics
Anti-Pseudomonas drugs (ceftazidime and imipenem) 25 (11.7) 38 (6.4) 0.015
Aminoglocosides
Glycopeptides 33 (15.4) 53 (9) 0.009
Quinolones 27(12.7) 37 (6.3) 0.003
Ureido-penicillin 49 (22.9) 78 (13.2) 0.0009
Antifungal agents 16(7.5) 17 (2.9) 0.0038
Duration of MV (range), d 13 (7-24) 6(3-12) < 0.0001
Duration of MV/ICU length of stay (range), d 82 (67-97) 75 (58-96) 0.008
Occurrence of VAP 51 (23.8) 114(19.3) 0.01
Occurrence of Pseudomonas VAP 19 (8.8) 30 (5) 0.1
Length of ICU stay (range), d 17 (9-32) 9 (5-17) < 0.0001
Length of hospital stay (range), d 36(19-74) 22 (9-45) < 0.0001
Outcome
ICU mortality 78 (36.4) 190 (32.3) 0.3
Hospital mortality 93 (43.5) 214 (36.3) 0.067

Figure-1

Figure 1. Patient flowchart.

This entry was posted in Pulmonary Function and tagged Candida, mechanical ventilation, pneumonia, Pseudomonas, ventilator-associated pneumonia.