Term | Explanation | Data Source |
---|---|---|

P(RTI) | Probability of a person consulting with RTI in a 30-day period | From RTI consultation rate per 30 days in CPRD |

P(AB|RTI) | Probability of receiving an AB prescription on the same date as an RTI consultation | From proportion of RTI consultations with AB prescribed, from CPRD |

P(PTA) | Probability of PTA, per 30 days | From incidence of PTA in CPRD |

P(RTI|PTA) | Probability of patients with PTA having consulted for an RTI in the 30 days preceding their PTA diagnosis | Proportion of PTA cases with previous RTI consultation, calculated from CPRD |

P(PTA|RTI) | Probability of PTA arising in the 30 days following an RTI consultation | |

P(PTA|[AB|RTI]) | Probability of patients with PTA having consulted for an RTI and received AB prescription | |

P(PTA|[No AB|RTI]) | Probability of patients with PTA having consulted for an RTI and not received an AB prescription | |

NNT | The number of additional antibiotic prescriptions required to prevent 1 case of PTA |

AB = antibiotic; CPRD = Clinical Practice Research Datalink; NNT = number needed to treat; P = probability; PTA = peritonsillar abscess; RTI = respiratory tract infection.