nnt {ClinSigMeasures}

Number Needed to Treat Calculation From a 2x2 Table

Description

Calculates number needed to treat and 95 percent confidence intervals for data from a 2x2 table

Usage

nnt(Cell1, Cell2, Cell3, Cell4)

Arguments

Cell1

Value for cases with a positive outcome

Cell2

Value for cases with a negative outcome

Cell3

Value for controls with a positive outcome

Cell4

Value for controls with a negative outcome

Value

Number Needed to Treat and 95 percent confidence intervals

Author(s)

Mike Malek-Ahmadi

References

1. Cook RJ, Sackett DL. The number needed to treat: a clinically useful measure of treatment effect [published correction appears in BMJ 1995 Apr 22;310(6986):1056]. BMJ. 1995;310(6977):452-454.

2. Zar HJ, Cotton MF, Strauss S et al Effect of isoniazid prophylaxi on mortality of tuberculosis in children with HIV: randomised controlled trial. BMJ 2007; 136-9.

Examples

#Mortality data from Zar et al (2007)

nnt(121, 11, 110, 21)