Beta-agonist type | FEV1 rate of change, mean percent predicted per year ± SE |

None | −1.297 ± 0.371 (122 visits) |

Beta-agonist | 0.125 ± 0.288 (187 visits) |

P = 0.002 | |

None | −1.311 ± 0.346 (122 visits) |

Short-acting | −0.393 ± 0.665 (48 visits) |

Both short-acting and long-acting | 0.493 ± 0.365 (104 visits) |

Long-acting | 0.880 ± 0.782 (35 visits) |

N vs. S | P = 0.2253 |

N vs. SL | P = 0.0004 |

N vs. L | P = 0.0113 |

S vs. SL | P = 0.2399 |

S vs. L | P = 0.2103 |

SL vs. L | P = 0.6525 |

With statistical correction, significant

*P*values are those less than 0.0083. L, long-acting beta-agonist; N, no beta agonist; S, short-acting beta-agonist; SL, short- and long-acting beta-agonists.