Outcome | No. of participants (%) | ||||||||

Total cohort (n=121) | Ureaplasma positive(n=44) | Ureaplasma negative(n=77) | |||||||

AZM (n=60) | Placebo (n=61) | P value* | AZM (n=19) | Placebo (n=25) | P value* | AZM (n=41) | Placebo (n=36) | P value* | |

Ureaplasma-free survival, n (%) | 55 (92) | 37 (61) | <0.001 | 16 (84) | 3 (12) | <0.001 | 39 (95) | 34 (94) | >0.99 |

Survival, n (%) | 55 (92) | 55 (90) | 0.78 | 16 (84) | 21 (84) | >0.99 | 39 (95) | 34 (94) | >0.99 |

Ureaplasma clearance post-treatment, n (%) | 19/19 (100) | 4/25 (16) | <0.001 | 19/19 (100) | 4/25 (16) | <0.001 | N/A | N/A | |

Discharged to home, n (%) | 39 (65) | 30 (49) | 0.10 | 13 (68) | 8 (32) | 0.03 | 26 (63) | 22 (61) | 0.86 |

Survival free of physiological BPD, n (%)† | 31/59 (53) | 36/59 (61) | 0.42 | 9 (47) | 13/24 (54) | 0.54 | 22 (55) | 23 (66) | 0.33 |

Physiological BPD, n (%)†‡ | 25/56 (45) | 18/54 (33) | 0.28 | 8/17 (47) | 8/21 (38) | 0.49 | 17/39 (44) | 10/33 (30) | 0.25 |

Modified Shennan BPD, n (%)‡ | 28/57 (49) | 23/56 (41) | 0.45 | 8/17 (47) | 11/22 (50) | 0.99 | 20/40 (50) | 12/34 (35) | 0.21 |

Moderate-severe BPD, n (%)‡ | 31/57 (54) | 23/56 (39) | 0.20 | 9/17 (53) | 10/22 (45%) | 0.51 | 22/40 (55) | 13/34 (38) | 0.15 |

Postnatal steroids exposure, n (%) | 15 (25) | 14 (23) | 0.86 | 7 (37) | 6 (24) | 0.33 | 8 (20) | 8 (22) | 0.74 |

Passed hearing screen, n (%)§ | 50/54 (93) | 52/54 (96) | 0.68 | 13/16 (81) | 19/21 (90) | 0.63 | 37/38 (97) | 33/33 (100) | >0.99 |

Duration IMV, median (IQR), days¶ | 12 (3–31) | 4 (1–44) | 0.36 | 15 (5–66) | 3 (1–44) | 0.25 | 11 (2–20) | 4 (1–47) | 0.51 |

Duration supplemental oxygen, median (IQR), days¶ | 73 (39–114.5) | 68 (33–118) | 0.94 | 87 (30–140) | 75 (55–135) | 0.98 | 70 (40–91) | 60 (26–94) | 0.81 |

Duration hospitalisation, median (IQR), days¶ | 87 (62.5–138.5) | 87 (67–111) | 0.91 | 109 (54–147) | 87 (59–111) | 0.62 | 83 (66–136) | 87 (72–112) | 0.53 |

*P values for binary outcomes are based on a score test from generalised estimating equations to account for correlations between twins, or Fisher’s exact test when one of the cell sizes has an expectation of less than 5. P values for quantitative outcomes are based on non-parametric tests using multiple outputation to account for correlations between twins.

†Three participants could not be classified with respect to physiological BPD and are excluded from these percentages.

‡Excludes eight participants (three azithromycin and five placebo) who died prior to BPD assessment.

§Based on only those who survived until discharge but excludes two survivors who did not have a hearing screen.

¶In computing the median and IQR, those who died are included as having the worst outcomes.

AZM, azithromycin; BPD, bronchopulmonary dysplasia; IMV, intermittent mandatory ventilation.