Table 3.
Multivariate hierarchical conditional logistic regression analysis of risk factors for CRE infection.
| CRE vs CSE |
CRE vs non-infected |
|||
|---|---|---|---|---|
| Adjusted OR (95% CI) | p | Adjusted OR (95% CI) | p | |
| Intrinsic features | ||||
| Age (per year) | – | – | 1.03 (1.01–1.05) | 0.001 |
| Chronic renal failure (moderate or severe) | 2.81 (1.40–5.64) | 0.004 | – | – |
| Epidemiological exposures | ||||
| Previous colonization/infection by CRE | 6.94 (2.74–17.53) | <0.001 | 13.14 (3.98–43.43) | <0.001 |
| Admission from home | 0.44 (0.23–0.85) | 0.014 | – | – |
| Previous hospitalization (last 6 months) | – | – | 1.84 (0.95–3.55) | 0.068 |
| Invasive procedures and therapies | ||||
| Urinary catheter (last week) | 1.78 (1.03–3.07) | 0.038 | 3.68 (1.86–7.28) | <0.001 |
| Immunosuppressive drugs | – | – | 3.38 (1.44–7.93) | 0.005 |
| Exposure to antibiotics | ||||
| MODEL A: Broad-spectrum anti-gram negative drugs | 2.20 (1.25–3.88)a | 0.006 | 2.89 (1.45–5.73)b | 0.002 |
| MODEL B: Days of broad-spectrum anti-gram negative drugs | 1.04 (1.00–1.07)c | 0.014 | 1.02 (0.99–1.04)d | 0.081 |
| MODEL C: Time of exposure to broad-spectrum drugs | ||||
| No broad spectrum anti-gram negative drugs | Refe | Ref | Reff | Ref |
| Broad spectrum anti-gram negative drugs, <6 days | 1.25 (0.57–2.71) | 0.56 | 3.00 (1.07–8.43) | 0.037 |
| Broad spectrum anti-gram negative drugs, ≥6 days | 2.86 (1.56–5.26) | 0.001 | 2.96 (1.44–6.06) | 0.003 |
| MODEL D: Number of broad-spectrum drugs | ||||
| None | Refg | Refh | ||
| One | 1.70 (1.00–2.90) | 0.050 | 2.03 (1.23–3.36) | 0.006 |
| ≥2 | 3.66 (1.77–7.58) | <0.001 | 2.95 (1.56–5.60) | <0.001 |
For exposures of antibiotics, different models were developed: model A included exposure to antibiotic groups as dichotomous variables; model B included duration of exposure to antibiotic groups; model C included only the risk category. Models with individual drugs did not provide significant associations and are not shown. The adjusted data for intrinsic features, epidemiological exposures, and invasive procedures and therapies were obtained for the model A, and were not significantly different for models B and C and therefore are not shown. Previous duration of hospital stay was included in all models.
Broad-spectrum anti-gram negative drugs: carbapenems, piperacillin-tazobactam, oxyimino-β-lactams, fluoroquinolones.
Reference categories for categorical exposures were “non-exposed” except where specified; for continuous variables (age, days of broad spectrum anti-gram negative drugs), the adjusted OR is per unit.
Area under the receiver operating characteristic curve (AUROC) for observed data of the models:
0.71 (95% CI: 0.67–0.75).
0.81 (95% CI: 0.78–0.84).
0.72 (95% CI: 0.68–0.76).
0.81 (95% CI: 0.78–0.84).
0.73 (95% CI: 0.69–0.77).
0.81 (95% CI: 0.78–0.84).
0.74 (0.70–0.78).
0.81 (0.78–0.84).