TABLE 2.
Cox regression analysis of predictive factors for the development of clinical infections due to P. aeruginosa
| Variablea | No. with clinical PA infection (%) (n = 77) | No. with nonclinical PA infection (%) (n = 337) | Crude analysis |
Adjusted analysis |
||
|---|---|---|---|---|---|---|
| HR (95% CI) | P value | HR (95% CI) | P value | |||
| Baseline feature | ||||||
| Age >65 yr | 40 (52) | 175 (52) | 1.02 (0.65–1.62) | 0.92 | ||
| Male | 57 (74) | 208 (62) | 0.88 (0.68–1.13) | 0.31 | ||
| Charlson score >2 | 40 (52) | 151 (45) | 1.49 (0.95–2.34) | 0.08 | 1.18 (0.7–2.01) | 0.531 |
| SAPS II >40 score at ICU admission | 45 (58) | 195 (58) | 1.01 (0.63–1.59) | 0.98 | ||
| Main underlying disease | ||||||
| Diabetes | 14 (18) | 94 (28) | 0.85 (0.47–1.52) | 0.58 | ||
| Chronic pulmonary disease | 17 (22) | 77 (23) | 1.05 (0.61–1.80) | 0.86 | ||
| Cardiovascular disease | 26 (34) | 124 (37) | 1.02 (0.63–1.63) | 0.95 | ||
| End-stage renal failure | 7 (9) | 47 (14) | 0.93 (0.43–2.05) | 0.86 | ||
| Chronic liver disease | 14 (18) | 40 (12) | 1.81 (1.01–3.24) | 0.046 | 1.52 (0.77–3.01) | 0.228 |
| Vascular/degenerative brain disease | 11 (14) | 34 (10) | 0.95 (0.50–4.82) | 0.89 | ||
| Malignant disease | 17 (22) | 72 (21) | 0.87 (0.50–1.53) | 0.64 | ||
| Immunosuppressed | 21 (27) | 86 (26) | 0.78 (0.56–1.55) | 0.78 | ||
| Prior hospital stay | 72 (94) | 156 (46) | 10.1 (4.08–25) | <0.001 | ||
| Prior surgery | 49 (64) | 182 (54) | 1.28 (0.80–2.06) | 0.29 | ||
| Hospital mortality | 26 (34) | 93 (28) | 1.41 (0.87–2.28) | 0.16 | ||
| Prior rectal colonization | 69 (90) | 107 (32) | 16.57 (7.53–36.49) | <0.001 | 15.23 (6.9–33.7) | <0.001 |
| Prior antibiotic use >10 days | 41 (53) | 155 (41) | 1.33 (0.80–2.12) | 0.27 | ||
| Fluoroquinolones | 12 (16) | 74 (22) | 0.42 (0.22–0.78) | 0.006 | 0.40 (0.21–0.76) | 0.005 |
| Carbapenems | 25 (32) | 96 (28) | 0.76 (0.48–1.26) | 0.30 | ||
| Antipseudomonal penicillins | 29 (38) | 128 (38) | 0.33 (0.20–0.54) | <0.001 | 0.39 (0.23–0.64) | <0.001 |
| Nonantipseudomonal penicillins | 34 (44) | 88 (26) | 1.71 (1.08–2.70) | 0.022 | 2.15 (1.3–3.55) | 0.003 |
| Antipseudomonal cephalosporins | 11 (15) | 25 (7) | 1.35 (0.71–2.57) | 0.36 | ||
| Nonantipseudomonal cephalosporins | 17 (22) | 31 (9) | 1.88 (1.08–3.27) | 0.026 | 1.05 (0.58–1.9) | 0.865 |
| Aminoglycosides | 3 (4) | 8 (2) | 1.01 (0.32–3.22) | 0.99 | ||
a
For the multivariate analyses, variables with a P value of <0.10 in the univariate analyses were included. To avoid colinearity problems, the final model does not include the prior hospital stay variable as it is nearly predicted by the prior colonization variable. Differential risks for development of prior rectal colonization were accounted for using a time-dependent variable within the model. Abbreviations: PA, Pseudomonas aeruginosa; HR, hazard ratio; CI, confidence interval.