You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
87 lines
2.9 KiB
Plaintext
87 lines
2.9 KiB
Plaintext
7 months ago
|
.-
|
||
|
|
help for ^metannt^
|
||
|
|
.-
|
||
|
|
|
||
|
|
Estimates of absolute benefit or risk from meta-analysis
|
||
|
|
--------------------------------------------------------
|
||
|
|
|
||
|
|
|
||
|
|
^metannt , measure(^or|rr|rd^) size(^#^) confint(^#,#^) baseline(^#[,#...#]^)^
|
||
|
|
|
||
|
|
|
||
|
|
Description
|
||
|
|
-----------
|
||
|
|
|
||
|
|
This program is intended to aid interpretation of meta-analyses of binary
|
||
|
|
data by presenting the effect sizes in absolute terms. Both the number
|
||
|
|
needed to treat (NNT) and the number of events avoided (or added) per
|
||
|
|
1000 are presented.
|
||
|
|
|
||
|
|
The ^Number Needed to Treat (NNT)^ is the number of individuals required
|
||
|
|
to experience the intervention in order to expect there to be one
|
||
|
|
additional event to be observed. Assuming the event is undesireable, this
|
||
|
|
is termed the "number needed to treat to benefit" (NNTB). If the
|
||
|
|
intervention arm experiences more events, this is commonly refered to as
|
||
|
|
the "number needed to treat to harm" (NNTH).
|
||
|
|
|
||
|
|
^metannt^ calculates this by deriving an effect size (e.g. a risk ratio),
|
||
|
|
applying it to a population with a given event prevalance, and from this
|
||
|
|
deriving a projected event rate if the population were to receive the
|
||
|
|
intervention. The NNT is equal to
|
||
|
|
1/(control group event rate - treatment group event rate).
|
||
|
|
|
||
|
|
The ^number of avoided or excess events (respectively) per 1000 population^
|
||
|
|
is the difference between the two event rates multiplied by 1000. The
|
||
|
|
intervention group event rate is calculated in the same manner as with
|
||
|
|
the NNT. Optionally a confidence interval is also presented, using the
|
||
|
|
confidence limits of the effect size applied to the control group event
|
||
|
|
rate.
|
||
|
|
|
||
|
|
Options for ^metannt^
|
||
|
|
-------------------
|
||
|
|
|
||
|
|
^baseline()^ specifies the baseline (ie. control group) event rates, from
|
||
|
|
which the NNT and number of events avoided are computed from. More than
|
||
|
|
one baseline event rate may be specified.
|
||
|
|
|
||
|
|
^measure(^rr|or|rd^)^ specifies whether the estimated effect size pooled is
|
||
|
|
a risk ratio, odds ratio or (absolute) risk difference.
|
||
|
|
|
||
|
|
^size(^#^)^ denotes the size of the effect
|
||
|
|
|
||
|
|
^confint(^#,#^)^ denotes the confidence interval around the effect size.
|
||
|
|
|
||
|
|
By default the saved results from the r() macros within @metan@ are used to
|
||
|
|
derive the control group event rate, the effect measure, the effect size and
|
||
|
|
its confidence interval. However, unless a recent version of metan (1.71
|
||
|
|
onwards) was used immediately beforehand, the first three options must be
|
||
|
|
specified. The confidence interval is optional.
|
||
|
|
|
||
|
|
|
||
|
|
Examples
|
||
|
|
--------
|
||
|
|
|
||
|
|
. ^metannt , measure(rr) size(0.2) baseline(0.1,0.2,0.3)^
|
||
|
|
|
||
|
|
. ^metan tdeath tnodeath cdeath cnodeath, or^
|
||
|
|
. ^metannt , baseline(0.15)^
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
Authors
|
||
|
|
-------
|
||
|
|
|
||
|
|
Michael J Bradburn, Jonathan J Deeks, Douglas G Altman.
|
||
|
|
Centre for Statistics in Medicine, Institute of Health Sciences,
|
||
|
|
Old Road, Headington, Oxford OX3 7LF, UK.
|
||
|
|
|
||
|
|
email mike.bradburn@@cancer.org.uk
|
||
|
|
|
||
|
|
Also see
|
||
|
|
--------
|
||
|
|
|
||
|
|
On-line: help for @metan@ (if installed), @meta@ (if installed)
|
||
|
|
|
||
|
|
|