Table 2.
Demographic and Clinical Characteristics of 879 Pediatric Patients Receiving Combination Therapy or Monotherapy for Gram-Negative Bacteremia, Before and After Propensity Score Adjustmenta
| Characteristic | Combination Therapy (n = 537) | Monotherapy, Unweighted (n = 342) | P Value, Combination vs Unweightedb | Monotherapy, Weightedc | P Value, Combination vs Weightedb |
|---|---|---|---|---|---|
| Age, mean (SD), y | 5.7 (6.4) | 6.4 (7.0) | .09 | 5.7 (6.5) | 0.99 |
| Female sex | 39.9 | 43.6 | .28 | 44.8 | 0.18 |
| Preexisting medical conditions | |||||
| Prematurity (≤33wk gestation) | 16.2 | 12.0 | .08 | 12.3 | .14 |
| Hematological | 3.9 | 8.5 | .01 | 11.3 | .07 |
| Neuromuscular | 6.1 | 9.4 | .09 | 10.0 | .08 |
| Cardiovascular | 8.2 | 5.8 | .18 | 7.0 | .55 |
| Respiratory | 6.7 | 5.6 | .49 | 8.0 | .66 |
| Gastrointestinal | 30.5 | 18.1 | <.001 | 21.0 | .01 |
| Renal | 8.4 | 9.4 | .62 | 10.0 | .58 |
| Immunocompromisedd | 16.0 | 22.2 | .02 | 20.3 | .16 |
| Cancer | 21.8 | 38.9 | <.001 | 26.3 | .20 |
| Genetic or metabolic | 10.4 | 7.0 | .08 | 9.0 | .56 |
| Second- or third-degree burns | 1.0 | 1.0 | .74 | 1.4 | .58 |
| No. of preexisting conditions, mean (SD) | 1.3 (0.6) | 1.2 (0.6) | .06 | 1.3 (0.6) | .19 |
| Highest PRISM III score, mean (SD) | 7.6 (8.8) | 7.1 (7.6) | .37 | 7.7 (8.4) | .99 |
| ICU admission | 46.7 | 35.7 | .001 | 45.0 | .57 |
| Vasopressors | 18.8 | 13.7 | .04 | 19.2 | .96 |
| Mechanical ventilation | 29.1 | 15.5 | <.001 | 24.6 | .19 |
| Time at risk, mean (SD), de | 17.9 (33.4) | 16.8 (35.2) | .09 | 19.4 (39.5) | .65 |
| Absolute neutrophil count ≤100 cells/μL | 13.1 | 10.2 | .01 | 12.2 | .35 |
| Central line in place 72 h after first positive blood culture result | 58.1 | 49.1 | .01 | 54.6 | .45 |
| Pseudomonas species bacteremia | 29.1 | 16.1 | <.001 | 19.3 | .01 |
| Other body sites where organism was recovered | |||||
| Urine | 12.7 | 7.3 | .01 | 6.5 | .003 |
| Pleural or bronchoalveolar lavage fluid | 4.5 | 5.3 | .60 | 2.5 | .27 |
| Bone or joint specimens | 1.0 | 2.0 | .13 | 3.5 | .08 |
| Intra-abdominal fluid | 1.0 | 1.8 | .32 | 1.6 | .61 |
| Cerebrospinal fluid | 1.7 | 1.0 | .12 | 1.3 | .60 |
Abbreviations: ICU, intensive care unit; PRISM, Pediatric Risk of Mortality.
Combination therapy included a β-lactam and an aminoglycoside; monotherapy, only a β-lactam. Data represent percentages unless otherwise indicated.
P value for t statistic for continuous variables and Pearson χ2 statistic for categorical variables.
The effective sample size was 233; this value captures the increase in sampling variance created by weighted means and gives an estimate of the number of patients receiving monotherapy who are comparable to those receiving combination therapy.
Immunocompromised patients include those receiving corticosteroid therapy (≥2 mg/kg for ≥14 d), immunomodulator therapy, hematopoietic stem cell transplant ≥1 y before onset of bacteremia, solid organ transplant, or cancer chemotherapy ≥6 mo before onset of bacteremia; those with congenital immunodeficiency; and those positive for human immunodeficiency virus (CD4+ T-cell count, <200 cells/mL).
Time at risk was defined as the number of days from hospital admission until the first positive blood culture result.