Age, median (IQR) | 41 (28–56) | 47 (29–60) | 37 (27–53) |

Female, n (%) | 68 (50.7) | 23 (48.9) | 45 (51.7) |

**Characteristics at ED presentation** | | | |

Oxygen saturation, %, median (IQR) | 97.5 (96–99) | 96 (95.5–98) | 96 (96–98) |

C-reactive protein, mg/L, median (IQR) | 8.4 (1.3–25.4) | 11 (3.7–24.7) | 6.9 (0.6–25.6) |

**Cohort trajectories** | | | |

Number of telephone encounters, median (range) | 1 (1–8) | 2 (1–8) | 1 (1–5) |

Total reattendances, n (%) | 12 (9.0) | 7 (14.6) | 5 (5.7) |

Planned reattendances, n (%) | 5 (3.7) | 3 (6.2) | 2 (2.3) |

Planned reattendances leading to admissions, n (%) | 2 (1.5) | 2 (1.3) | – |

Unplanned reattendances, n (%) | 7 (5.2)^{a} | 4 (8.3)^{b} | 3 (3.4) |

Unplanned reattendances leading to admissions, n (%) | 3 (2.2) | 3 (6.2) | – |