### Abstract

Objective: The objective of this study was to present ways to graphically represent a number needed to treat (NNT) in (network) meta-analysis (NMA). Study Design and Setting: A barrier to using NNT in NMA when an odds ratio (OR) or risk ratio (RR) is used is the determination of a single control event rate (CER). We discuss approaches to calculate a CER, and illustrate six graphical methods for NNT from NMA. We illustrate the graphical approaches using an NMA of cognitive enhancers for Alzheimer's dementia. Results: The NNT calculation using a relative effect measure, such as OR and RR, requires a CER value, but different CERs, including mean CER across studies, pooled CER in meta-analysis, and expert opinion-based CER may result in different NNTs. An NNT from NMA can be presented in a bar plot, Cates plot, or forest plot for a single outcome, and a bubble plot, scatterplot, or rank-heat plot for ≥2 outcomes. Each plot is associated with different properties and can serve different needs. Conclusion: Caution is needed in NNT interpretation, as considerations such as selection of effect size and CER, and CER assumption across multiple comparisons, may impact NNT and decision-making. The proposed graphs are helpful to interpret NNTs calculated from (network) meta-analyses.

Original language | English |
---|---|

Pages (from-to) | 11-22 |

Number of pages | 12 |

Journal | Journal of Clinical Epidemiology |

Volume | 111 |

Early online date | 21 Mar 2019 |

DOIs | |

Publication status | Published - 1 Jul 2019 |

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*Journal of Clinical Epidemiology*,

*111*, 11-22. https://doi.org/10.1016/j.jclinepi.2019.03.007

}

*Journal of Clinical Epidemiology*, vol. 111, pp. 11-22. https://doi.org/10.1016/j.jclinepi.2019.03.007

**The number needed to treat in pairwise and network meta-analysis and its graphical representation.** / Veroniki, Areti Angeliki; Bender, Ralf; Glasziou, Paul; Straus, Sharon E.; Tricco, Andrea C.

Research output: Contribution to journal › Article › Research › peer-review

TY - JOUR

T1 - The number needed to treat in pairwise and network meta-analysis and its graphical representation

AU - Veroniki, Areti Angeliki

AU - Bender, Ralf

AU - Glasziou, Paul

AU - Straus, Sharon E.

AU - Tricco, Andrea C.

PY - 2019/7/1

Y1 - 2019/7/1

N2 - Objective: The objective of this study was to present ways to graphically represent a number needed to treat (NNT) in (network) meta-analysis (NMA). Study Design and Setting: A barrier to using NNT in NMA when an odds ratio (OR) or risk ratio (RR) is used is the determination of a single control event rate (CER). We discuss approaches to calculate a CER, and illustrate six graphical methods for NNT from NMA. We illustrate the graphical approaches using an NMA of cognitive enhancers for Alzheimer's dementia. Results: The NNT calculation using a relative effect measure, such as OR and RR, requires a CER value, but different CERs, including mean CER across studies, pooled CER in meta-analysis, and expert opinion-based CER may result in different NNTs. An NNT from NMA can be presented in a bar plot, Cates plot, or forest plot for a single outcome, and a bubble plot, scatterplot, or rank-heat plot for ≥2 outcomes. Each plot is associated with different properties and can serve different needs. Conclusion: Caution is needed in NNT interpretation, as considerations such as selection of effect size and CER, and CER assumption across multiple comparisons, may impact NNT and decision-making. The proposed graphs are helpful to interpret NNTs calculated from (network) meta-analyses.

AB - Objective: The objective of this study was to present ways to graphically represent a number needed to treat (NNT) in (network) meta-analysis (NMA). Study Design and Setting: A barrier to using NNT in NMA when an odds ratio (OR) or risk ratio (RR) is used is the determination of a single control event rate (CER). We discuss approaches to calculate a CER, and illustrate six graphical methods for NNT from NMA. We illustrate the graphical approaches using an NMA of cognitive enhancers for Alzheimer's dementia. Results: The NNT calculation using a relative effect measure, such as OR and RR, requires a CER value, but different CERs, including mean CER across studies, pooled CER in meta-analysis, and expert opinion-based CER may result in different NNTs. An NNT from NMA can be presented in a bar plot, Cates plot, or forest plot for a single outcome, and a bubble plot, scatterplot, or rank-heat plot for ≥2 outcomes. Each plot is associated with different properties and can serve different needs. Conclusion: Caution is needed in NNT interpretation, as considerations such as selection of effect size and CER, and CER assumption across multiple comparisons, may impact NNT and decision-making. The proposed graphs are helpful to interpret NNTs calculated from (network) meta-analyses.

UR - http://www.scopus.com/inward/record.url?scp=85064198314&partnerID=8YFLogxK

U2 - 10.1016/j.jclinepi.2019.03.007

DO - 10.1016/j.jclinepi.2019.03.007

M3 - Article

VL - 111

SP - 11

EP - 22

JO - Journal of Chronic Diseases

JF - Journal of Chronic Diseases

SN - 0895-4356

ER -