Table 1 Characteristics at birth and at T0 (beginning of antibiotic treatment)
Group 1*Group 2†p Value
Number7372
At birth
    Male (n (%))32 (44)38 (53)0.5
    Birth weight (g)944 (800–1160)870 (760–1160)0.64
    Post-conceptional age (weeks)28 (26–29)27.5 (26–29)0.83
    Post-conceptional age <28 weeks34 (46)36 (50)0.7
    (n (%))
At time zero
    Postnatal age (days)11 (7–18)10 (8–15)0.83
    Body weight (g)938 (795–1140)870 (707–1170)0.95
    Serum creatinine (μmol/l)70 (60–86)74 (55–104)0.34
    Serum creatinine <90 μmol/l (n (%))60 (82)50 (69)0.07
    Treated patent ductus arteriosus (n (%))11 (15)14( 19)0.48
    Central venous line65 (89)63 (88)0.25
    (n (%))

  • Data are median (Q25–Q75) or number (%).

  • *Group 1: 15 mg/kg/day or 25 mg/kg/day depending on whether serum creatinine was > or ⩽90 μmol/l.

  • †Group 2: 20 mg/kg/day or 30 mg/kg/day depending on whether serum creatinine was > or ⩽90 μmol/l.