Number needed to treat: A useful new method of assessing the magnitude of treatment effect and its application to the management of diabetic retinopathy

J. A. San Laureano, E. M. Briganti, D. J. Colville

Research output: Contribution to journalReview ArticleResearchpeer-review

9 Citations (Scopus)


The magnitude of treatment effect from randomized controlled trials can be measured in various ways. The number needed to treat is a recently described measure that has been shown to offer several advantages in the clinical interpretation and application of reported treatment effects. It quantifies the number of patients that must be treated in order to prevent one patient from developing the specified outcome. The methods necessary to calculate traditional measures of treatment effect, as well as the number needed to treat, are outlined using the management of diabetic retinopathy as an example. The uses and limitations of the number needed to treat are also discussed.

Original languageEnglish
Pages (from-to)137-142
Number of pages6
JournalAustralian and New Zealand Journal of Ophthalmology
Issue number2
Publication statusPublished - 6 Jul 1999


  • Clinical decision making
  • Clinical epidemiology
  • Diabetic retinopathy
  • Number needed to treat
  • Treatment effect

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