Update an existing meta-analysis object.

```
# S3 method for meta
update(object, data = object$data,
subset = object$subset, studlab = object$data$.studlab,
exclude = object$data$.exclude, method = object$method,
sm = object$sm, incr, allincr = object$allincr,
addincr = object$addincr, allstudies = object$allstudies,
MH.exact = object$MH.exact, RR.cochrane = object$RR.cochrane,
model.glmm = object$model.glmm, level = object$level,
level.comb = object$level.comb, comb.fixed = object$comb.fixed,
comb.random = object$comb.random, hakn = object$hakn,
method.tau = object$method.tau, tau.preset = object$tau.preset,
TE.tau = object$TE.tau, tau.common = object$tau.common,
prediction = object$prediction, level.predict = object$level.predict,
null.effect = object$null.effect, method.bias = object$method.bias,
backtransf = object$backtransf, pscale = object$pscale,
irscale = object$irscale, irunit = object$irunit,
title = object$title, complab = object$complab,
outclab = object$outclab, label.e = object$label.e,
label.c = object$label.c, label.left = object$label.left,
label.right = object$label.right, n.e = object$n.e,
n.c = object$n.c, pooledvar = object$pooledvar,
method.smd = object$method.smd, sd.glass = object$sd.glass,
exact.smd = object$exact.smd, method.ci = object$method.ci,
byvar = object$byvar, bylab = object$bylab,
print.byvar = object$print.byvar, byseparator = object$byseparator,
print.CMH = object$print.CMH, keepdata = TRUE, left = object$left,
ma.fixed = object$ma.fixed, type = object$type,
n.iter.max = object$n.iter.max, warn = object$warn,
control = object$control, ...)
```

object

An object of class `meta`

.

data

Dataset.

subset

Subset.

studlab

Study label.

exclude

An optional vector specifying studies to exclude from meta-analysis, however, to include in printouts and forest plots.

method

sm

A character string indicating which summary measure is used for pooling.

incr

Either a numerical value or vector which can be added
to each cell frequency for studies with a zero cell count or the
character string `"TA"`

which stands for treatment arm
continuity correction.

allincr

A logical indicating if `incr`

is added to each
cell frequency of all studies if at least one study has a zero
cell count. If FALSE (default), `incr`

is added only to each
cell frequency of studies with a zero cell count.

addincr

A logical indicating if `incr`

is added to each
cell frequency of all studies irrespective of zero cell counts.

allstudies

A logical indicating if studies with zero or all
events in both groups are to be included in the meta-analysis
(applies only if `sm`

is equal to `"RR"`

or
`"OR"`

).

MH.exact

A logical indicating if `incr`

is not to be
added to all cell frequencies for studies with a zero cell count
to calculate the pooled estimate based on the Mantel-Haenszel
method.

RR.cochrane

A logical indicating if 2*`incr`

instead of
1*`incr`

is to be added to `n.e`

and `n.c`

in the
calculation of the risk ratio (i.e., `sm = "RR"`

) for
studies with a zero cell. This is used in RevMan 5, the Cochrane
Collaboration's program for preparing and maintaining Cochrane
reviews.

model.glmm

A character string indicating which GLMM model should be used.

level

The level used to calculate confidence intervals for individual studies.

level.comb

The level used to calculate confidence intervals for pooled estimates.

comb.fixed

A logical indicating whether a fixed effect meta-analysis should be conducted.

comb.random

A logical indicating whether a random effects meta-analysis should be conducted.

hakn

A logical indicating whether the method by Hartung and Knapp should be used to adjust test statistics and confidence intervals.

method.tau

A character string indicating which method is
used to estimate the between-study variance \(\tau^2\). Either
`"DL"`

, `"PM"`

, `"REML"`

, `"ML"`

,
`"HS"`

, `"SJ"`

, `"HE"`

, or `"EB"`

, can be
abbreviated. See function `metagen`

.

tau.preset

Prespecified value for the square-root of the between-study variance \(\tau^2\).

TE.tau

Overall treatment effect used to estimate the between-study variance \(\tau^2\).

tau.common

A logical indicating whether tau-squared should be the same across subgroups.

prediction

A logical indicating whether a prediction interval should be printed.

level.predict

The level used to calculate prediction interval for a new study.

null.effect

A numeric value specifying the effect under the null hypothesis.

method.bias

A character string indicating which test for
funnel plot asymmetry is to be used. Either `"rank"`

,
`"linreg"`

, `"mm"`

, `"count"`

, `"score"`

, or
`"peters"`

, can be abbreviated. See function
`metabias`

backtransf

A logical indicating whether results should be
back transformed in printouts and plots. If ```
backtransf =
TRUE
```

, results for `sm = "OR"`

are printed as odds ratios
rather than log odds ratios and results for `sm = "ZCOR"`

are printed as correlations rather than Fisher's z transformed
correlations, for example.

pscale

A numeric giving scaling factor for printing of
single event probabilities or risk differences, i.e. if argument
`sm`

is equal to `"PLOGIT"`

, `"PLN"`

,
`"PRAW"`

, `"PAS"`

, `"PFT"`

, or `"RD"`

.

irscale

A numeric defining a scaling factor for printing of
single incidence rates or incidence rate differences, i.e. if
argument `sm`

is equal to `"IR"`

, `"IRLN"`

,
`"IRS"`

, `"IRFT"`

, or `"IRD"`

.

irunit

A character specifying the time unit used to calculate rates, e.g. person-years.

title

Title of meta-analysis / systematic review.

complab

Comparison label.

outclab

Outcome label.

label.e

Label for experimental group.

label.c

Label for control group.

label.left

Graph label on left side of forest plot.

label.right

Graph label on right side of forest plot.

n.e

Number of observations in experimental group. (only for metagen object)

n.c

Number of observations in control group. (only for metagen object)

pooledvar

A logical indicating if a pooled variance should
be used for the mean difference (only for metacont object with
`sm = "MD"`

).

method.smd

A character string indicating which method is
used to estimate the standardised mean difference (only for
metacont object with `sm = "SMD"`

). Either `"Hedges"`

for Hedges' g (default), `"Cohen"`

for Cohen's d, or
`"Glass"`

for Glass' delta, can be abbreviated.

sd.glass

A character string indicating which standard
deviation is used in the denominator for Glass' method to
estimate the standardised mean difference (only for metacont
object with `sm = "SMD"`

). Either `"control"`

using the
standard deviation in the control group (`sd.c`

) or
`"experimental"`

using the standard deviation in the
experimental group (`sd.e`

), can be abbreviated.

exact.smd

A logical indicating whether exact formulae should be used in estimation of the standardised mean difference and its standard error.

method.ci

A character string indicating which method is used
to calculate confidence intervals for individual studies. Either
`"CP"`

, `"WS"`

, `"WSCC"`

, `"AC"`

,
`"SA"`

,, `"SACC"`

, or `"NAsm"`

, can be
abbreviated. See function `metaprop`

.

byvar

An optional vector containing grouping information
(must be of same length as `event.e`

).

bylab

A character string with a label for the grouping variable.

print.byvar

A logical indicating whether the name of the grouping variable should be printed in front of the group labels.

byseparator

A character string defining the separator between label and levels of grouping variable.

print.CMH

A logical indicating whether result of the Cochran-Mantel-Haenszel test for overall effect should be printed.

keepdata

A logical indicating whether original data (set) should be kept in meta object.

left

A logical indicating whether studies are supposed to be
missing on the left or right side of the funnel plot. If NULL,
the linear regression test for funnel plot symmetry (i.e.,
function `metabias(..., method = "linreg")`

) is used to
determine whether studies are missing on the left or right side.

ma.fixed

A logical indicating whether a fixed effect or random effects model is used to estimate the number of missing studies.

type

A character indicating which method is used to estimate
the number of missing studies. Either `"L"`

or `"R"`

.

n.iter.max

Maximum number of iterations to estimate number of missing studies.

warn

A logical indicating whether warnings should be printed
(e.g., if `incr`

is added to studies with zero cell
frequencies).

control

…

Additional arguments (ignored at the moment).

An object of class `"meta"`

and `"metabin"`

,
`"metacont"`

, `"metacor"`

, `"metainc"`

,
`"metagen"`

, `"metamean"`

, `"metaprop"`

, or
`"metarate"`

.

Wrapper function to update an existing meta-analysis object which
was created with R function `metabin`

,
`metacont`

, `metacor`

,
`metagen`

, `metainc`

,
`metamean`

, `metaprop`

, or
`metarate`

. More details on function arguments are
available in help files of respective R functions

This function can also be used for objects of class 'trimfill', 'metacum', and 'metainf'.

`metabin`

, `metacont`

,
`metacor`

, `metagen`

,
`metainc`

, `metamean`

,
`metaprop`

, `metarate`

```
# NOT RUN {
data(Fleiss93cont)
m1 <- metacont(n.e, mean.e, sd.e, n.c, mean.c, sd.c,
data = Fleiss93cont, sm = "SMD", studlab = study)
m1
# Change summary measure (from 'SMD' to 'MD')
#
update(m1, sm = "MD")
# Restrict analysis to subset of studies
#
update(m1, subset = 1:2)
# Use different levels for confidence intervals
#
m2 <- update(m1, level = 0.66, level.comb = 0.99)
print(m2, digits = 2)
forest(m2)
# }
```

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