Table 3. Risk factors for lower β-lactam serum concentrations than pharmacodynamic targets of the free fraction greater than 1 times the MIC (fT >MIC) and the total serum concentration greater than 4 times the MIC (T >4MIC) of P. aeruginosa for 40%, 50% and 70% of dosing interval for meropenem, piperacillin-tazobactam and cefepime/ceftazidime, respectively.
| Variable | fT <MIC for specified time period (n=14) | fT >MIC for specified time period (n=42) |
Univariate analysis |
Multivariate analysis |
T <4MIC for specified time period (n=45) | T >4MIC for specified time period (n=11) |
Uni-variate analysis |
Multivariate analysis |
||
|---|---|---|---|---|---|---|---|---|---|---|
| P-value | P-value | OR (95% CI) | P-value | P-value | OR (95% CI) | |||||
| Male | 7 (50.0) | 21 (50.0) | 1.0 | 21(46.7) | 7 (63.6) | 0.32 | ||||
| Weight | 106 (91–141) | 103 (80–153) | 0.43 | 102.5 (85–152.5) | 110 (80–152.5) | 0.58 | ||||
| Body mass index (kg m−2) | 37 (30–46.1) | 35 (30–54) | 0.93 | 36 (30–48) | 38 (30–54) | 0.55 | ||||
| CrCL24h (ml min−1; n=52) | 155 (76–390) | 86 (6–305) | 0.01 | 0.01 | 0.980–0.996 | 113 (23–305) | 37 (6–142) | 0.003 | 0.006 | 0.929–0.987 |
| Early serum sampling | 6 (42.9) | 17 (40.5) | 0.88 | 17 (37.8) | 6 (54.6) | 0.32 | ||||
| Abdominal circumference (cm; n=47) | 127 (118–158) | 127 (99–177) | 0.83 | 125 (99–177) | 132 (124–161) | 0.03 | 0.067 | 0.997–1.104 | ||
| Body surface area (m2) | 2.2 (2–2.5) | 2.1 (1.8–2.6) | 0.25 | 2.1 (1.8–2.6) | 2.1 (1.9–2.6) | 0.68 | ||||
| Ideal body weight (kg) | 68 (54–78) | 60 (41–80) | 0.23 | 65 (41–78) | 60 (48–80) | 0.75 | ||||
| Fat-free mass (kg) | 58 (53–72) | 58 (47–74) | 0.25 | 58 (47–74) | 57 (52–74) | 0.68 | ||||
| Lean body weight (kg) | 64 (50–77) | 58 (35–80) | 0.46 | 58 (38–77) | 61 (35–80) | 0.72 | ||||
| Adjusted body weight (kg) | 82 (71–101) | 79 (61–105) | 0.26 | 80 (61–101) | 79 (70–105) | 0.61 | ||||
| Percent ideal body weight (%) | 176 (129–214) | 160 (131–272) | 0.75 | 162 (128–272) | 165 (129–225) | 0.77 | ||||
| Meropenem | 1 (7.1) | 13 (31.0) | 0.20 | 12 (26.7) | 2 (18.2) | 0.84 | ||||
| Piperacillin-tazobactam | 10 (71.4) | 21 (50.0) | 0.10 | 24 (53.3) | 7 (63.6) | 0.87 | ||||
| Cefepime or ceftazidime | 3 (21.4) | 8 (19.1) | 0.23 | 9 (20.0) | 2 (18.2) | 0.98 | ||||
Abbreviations: CI, confidence interval; CrCL24h, measured creatinine clearance with 24-h urine collect; MIC, minimal inhibition concentration; OR, odds ratio.
Data are expressed as counts (percentage) or median (range). Boldface indicates significant P-value.