Unadjusted coefficient | IRR | 95% CI (IRR) | p-value | Adjusted coefficient^{#} | IRR | 95% CI (IRR) | p-value | |

Intercept | 1.76 | 5.83 | 3.97–8.56 | <0.001 | 1.48 | 4.38 | 2.82–6.79 | <0.001 |

Time | 0.15 | 1.16 | 1.07–1.26 | <0.001* | 0.15 | 1.16 | 1.07–1.26 | <0.001* |

CFTR modulator | −1.28 | 0.28 | 0.19–0.40 | <0.001* | −1.28 | 0.28 | 0.19–0.40 | <0.001* |

Time : CFTR modulator | 0.16 | 1.18 | 0.93–1.49 | 0.170 | 0.17 | 1.19 | 0.94–1.50 | 0.153 |

Interpretation: coefficients are on the log-scale. Incidence rate ratios (IRRs) are transformed back to the original scale. The IRR of the intercept represents the mean duration of received *i.v*. antibiotics (in days) of the study population at the time of CFTR modulator initiation (baseline). The IRR of time shows the relative annual change in the duration of *i.v.* antibiotics before CFTR modulator treatment. The IRR of CFTR modulator reflects the acute change in the duration of *i.v.* antibiotics in the first year after CFTR modulator initiation, whereas time : CFTR modulator treatment indicates the relative change of *i.v.* antibiotic treatment in the years after modulator initiation compared to the annual trend before CFTR modulator use. CFTR: cystic fibrosis transmembrane conductance regulator. ^{#}: coefficients and IRRs were adjusted for sex and age at baseline; *: significance level p<0.05.