Expand multiarm trials

This is a function to expand the format of meta-analysis data for its applicability to the calculateEffectSizes function of the metapsyTools-package.

Usage

expandMultiarmTrials(data,
                     vars.for.id = c("study", "primary",
                                     "Outc_measure",
                                     "Time", "Time_weeks",
                                     "sr_clinician"),
                     study.indicator = "study",
                     multiarm.indicator = "is.multiarm",
                     no.arms.indicator = "no.arms",
                     group.indicator = "condition",
                     condition.specification = "Cond_spec",
                     groups.column.indicator = c("_trt1", "_trt2"),
                     group.names = list("ig" = "ig",
                                        "cg" = "cg"),
                     data.format = NULL)

Arguments

data: Meta-analysis data stored as a data.frame.
vars.for.id: character vector, containing column names of all variables used to construct unique comparison IDs.
study.indicator: character, signifying the name of the variable containing the study name.
multiarm.indicator: numeric, signifying if a row is part of a multiarm study (1) or not (0).
no.arms.indicator: character, signifying the name of the variable containing the number of arms included in a study (typically 2).
group.indicator: character, column name of the variable storing the study name.
condition.specification: character, column name of the variable storing the trial condition name.
groups.column.indicator: character. If the dataset is in wide format: a character vector with two elements, representing the suffix used to differentiate between the first and second treatment in a comparison.
group.names: list, storing the name of the value corresponding to the intervention group ("ig") and control group ("cg").
data.format: character. Either "long" or "wide", depending on the format of the dataset in data. NULL by default, which lets the user define the format after the function has been called.

Value

expandMultiarmTrials returns the meta-analysis data set as class data.frame (if results are saved to a variable). The rows of multiarm studies are expanded so that each intervention group has an unambiguously assigned control group. It also generates the following columns:

id a comparison-specific ID variable.
study.id a study-specific ID variable.
study a study-specific variable containing the study name. For multiarm studies, this variable also specifies the active treatment indicated by multiarm.group.indicator behind the name of the study (e.g. "Hauksson, 2017 -grp").

Details

This function expands multiarm studies in a meta-analysis data set, thereby ensuring that each comparison (intervention group vs. control group in condition) is unique for a specific outcome, and thus has two rows. For this purpose, it duplicates the corresponding row of the control group condition if required. A specific study indicator variable is created that enables further use, e.g. in 3-level models. For more details see the help vignette: vignette("metapsyTools").

Author

Mathias Harrer mathias.h.harrer@gmail.com, Paula Kuper paula.r.kuper@gmail.com, Pim Cuijpers p.cuijpers@vu.nl

Examples

if (FALSE) {
data("inpatients")
expandMultiarmTrials(inpatients)
}