Number of studies | Median per cent of sample randomised | First and third quartile (%) | Minimum and maximum (%) | |
---|---|---|---|---|

Screened | 24 | 530 | 243, 773 | 100, 7067 |

Eligible | 27 | 132 | 108, 172 | 100, 448 |

Declined | 22 | 18 | 8, 144 | 3, 4942 |

Sample size | 33 | 96 | 90, 110 | 49, 323 |

Outcome assessed | 61 | 96 | 90, 100 | 52, 100 |

‘Number of studies’ refers to the number of trials that provided relevant data. Trials terminated early are included in these analyses. ‘Sample size’ refers to the sample size required to reach statistical power, not inflated to account for drop-outs. ‘Outcome assessed’ refers to total number of patients, in both arms. The denominator is the number of patients actually randomised into each trial.