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The Numbers Needed to Treat for Neurological Disorders

Published online by Cambridge University Press:  02 December 2014

Miguel Bussière  and
Samuel Wiebe
Miguel Bussière*
Affiliation:
Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada
Samuel Wiebe
Affiliation:
Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
*
Division of Neurology, Department of Clinical Neurological Sciences, University of Western Ontario, 339 Windermere Road, Rm 7-GE6, London, Ontario, N6A 5A5, Canada
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Abstract:

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Background:

Numerous therapeutic interventions have been developed in the neurosciences. Clinicians need summary measures about efficacy of therapies that derive from the best available evidence, and that can be readily extrapolated to clinical practice. The number needed to treat (NNT) is intuitive and clinically applicable. We provide clinicians with a single source that summarizes important therapies in the main neurological and neurosurgical areas.

Methods:

Critically appraised evidence about therapies in the neurosciences was obtained from meta-analyses in all neurosciences groups in the Cochrane library, and from critically appraised topics at the University of Western Ontario. Therapies were included if they were deemed relevant and if outcomes were dichotomous. For each therapy, we obtained absolute risk differences and their 95% confidence intervals (CI), the corresponding NNTs, control and experimental event rates, and the time-frame of the outcome assessment.

Results:

We assembled a table of NNTs for 87 interventions in ten disease categories, deriving from meta-analyses (70%) or randomized controlled trials (30%), and assessing surgical interventions (7%), procedures (9%) or pharmacological treatments (84%). The NNTs varied widely, ranging from 1 in the use of epidural blood patch for post-dural puncture headache to 4608 for meningococcal vaccination. Preventative interventions had substantially larger NNTs. Time-frames were inappropriately short for many chronic conditions.

Conclusions:

Large collections of NNTs provide useful, updateable summaries of therapeutic effects in the neurosciences, an increasingly interventional clinical field.

Résumé:

RÉSUMÉ: Contexte:

De nombreux traitements ont été développés en neurosciences. Les cliniciens ont besoin d’une synthèse fondée sur les meilleures données sur l’efficacité de ces traitements, qui peut être facilement appliquée en pratique clinique. Nous fournissons aux cliniciens une source unique qui fait un sommaire des traitements importants dans les principaux domaines de la neurologie et de la neurochirurgie.

Méthodes:

Des données ayant fait l’objet d’une évaluation critique ont été tirées de méta-analyses en neurosciences dans la bibliothèque Cochrane et de sujets ayant fait l’objet d’une évaluation critique à l’Université Western Ontario. Les traitements n’ont été inclus que s’ils étaient considérés pertinents et si les résultats présentaient une dichotomie. Pour chaque traitement, nous avons présentons les différences du risque absolu ainsi que l’intervalle de confiance de 95%, le nombre de patients devant être traités (NPT), le taux d’incidents thérapeutiques dans le groupe témoin et le groupe expérimental et la durée de l’étude.

Résultats:

Nous fournissons une table de NPT pour 87 interventions dans 10 catégories de maladies. Ces données proviennent de méta-analyses (70%) ou d’études contrôlées randomisées (30%) et évaluent des interventions chirurgicales (7%), des techniques (9%) ou des traitements pharmacologiques (84%). Les NPT variaient considérablement, allant de 1 pour le blood-patch épidural pour traiter la céphalée suite à une brèche de la dure-mère, à 4608 pour la vaccination anti-méningococcique. Les interventions préventives comportaient des NPT considérablement plus élevés. La durée des études sur plusieurs maladies était trop courte.

Conclusions:

Un recueil de NPT fournit un sommaire utile, qui peut être mis à jour, sur les effets des traitements en neurosciences, un champ clinique où il y a de plus en plus d’interventions.

Type
Original Article
Information
Canadian Journal of Neurological Sciences , Volume 32 , Issue 4 , November 2005 , pp. 440 - 449
Copyright
Copyright © The Canadian Journal of Neurological 2005

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