derive_param_waisthgt {admiralmetabolic} | R Documentation |
Adds a Parameter for Waist to Height Ratio
Description
Adds a parameter for Waist to Height Ratio using Waist Circumference and Height for each by group (e.g., subject and visit) where the source parameters are available.
Note: This is a wrapper function for the more generic admiral::derive_param_computed()
.
Usage
derive_param_waisthgt(
dataset,
by_vars,
wstcir_code = "WSTCIR",
height_code = "HEIGHT",
set_values_to = exprs(PARAMCD = "WAISTHGT"),
filter = NULL,
constant_by_vars = NULL,
get_unit_expr
)
Arguments
dataset |
Input dataset The variables specified by the The variable specified by |
by_vars |
Grouping variables For each group defined by Permitted Values: list of variables created by |
wstcir_code |
Waist Circumference parameter code The observations where Permitted Values: character value |
height_code |
Height parameter code The observations where Permitted Values: character value |
set_values_to |
Variables to be set The specified variables are set to the specified values for the new
observations. For example Permitted Values: List of variable-value pairs |
filter |
Filter condition The specified condition is applied to the input dataset before deriving the new parameter, i.e., only observations fulfilling the condition are taken into account. Permitted Values: a condition |
constant_by_vars |
By variables for when Height is constant When Height is constant, the Height parameters (measured only once) are merged to the other parameters using the specified variables. If Height is constant (e.g. only measured once at screening or baseline) then use
Permitted Values: list of variables created by |
get_unit_expr |
An expression providing the unit of the parameter The result is used to check the units of the input parameters. If the units are not consistent within each parameter, an error will be thrown. Additionally, if the input parameters are measured in different units but are mutually convertible (e.g., centimeters for one parameter and inches for another), an automatic conversion will be performed in order to uniform the values before calculating the ratio. Note: Conversion factors come from unit definitions as per CDISC standards.
Permitted Values: A variable of the input dataset or a function call |
Details
The analysis value of the new parameter is derived as
WAISTHGT = \frac{WSTCIR}{HEIGHT}
Value
The input dataset with the new parameter added. Note, a variable will only
be populated in the new parameter rows if it is specified in by_vars
.
See Also
admiral::derive_param_computed()
ADVS Functions for adding Parameters:
derive_param_waisthip()
Examples
library(tibble)
library(rlang)
# Example 1: Derive Waist to Height Ratio where Height is measured only once
advs <- tribble(
~USUBJID, ~PARAMCD, ~PARAM, ~AVAL, ~AVALU, ~VISIT,
"01-101-1001", "HEIGHT", "Height (cm)", 147, "cm", "SCREENING",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 110, "cm", "SCREENING",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 108, "cm", "WEEK 2",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 107, "cm", "WEEK 3",
"01-101-1002", "HEIGHT", "Height (cm)", 163, "cm", "SCREENING",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 120, "cm", "SCREENING",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 118, "cm", "WEEK 2",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 117, "cm", "WEEK 3",
)
derive_param_waisthgt(
advs,
by_vars = exprs(USUBJID, VISIT),
wstcir_code = "WSTCIR",
height_code = "HEIGHT",
set_values_to = exprs(
PARAMCD = "WAISTHGT",
PARAM = "Waist to Height Ratio"
),
constant_by_vars = exprs(USUBJID),
get_unit_expr = admiral::extract_unit(PARAM)
)
# Example 2: Same as above but only adding Waist to Height Ratio
# at certain visits
derive_param_waisthgt(
advs,
by_vars = exprs(USUBJID, VISIT),
wstcir_code = "WSTCIR",
height_code = "HEIGHT",
set_values_to = exprs(
PARAMCD = "WAISTHGT",
PARAM = "Waist to Height Ratio"
),
constant_by_vars = exprs(USUBJID),
get_unit_expr = admiral::extract_unit(PARAM),
filter = VISIT %in% c("SCREENING", "WEEK 3")
)
# Example 3: Pediatric study where Height and Waist Circumference
# are measured multiple times
advs <- tribble(
~USUBJID, ~PARAMCD, ~PARAM, ~AVAL, ~AVALU, ~VISIT,
"01-101-1001", "HEIGHT", "Height (cm)", 147, "cm", "SCREENING",
"01-101-1001", "HEIGHT", "Height (cm)", 148, "cm", "WEEK 2",
"01-101-1001", "HEIGHT", "Height (cm)", 149, "cm", "WEEK 3",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 100, "cm", "SCREENING",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 99, "cm", "WEEK 2",
"01-101-1001", "WSTCIR", "Waist Circumference (cm)", 98, "cm", "WEEK 3",
"01-101-1002", "HEIGHT", "Height (cm)", 163, "cm", "SCREENING",
"01-101-1002", "HEIGHT", "Height (cm)", 164, "cm", "WEEK 2",
"01-101-1002", "HEIGHT", "Height (cm)", 165, "cm", "WEEK 3",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 110, "cm", "SCREENING",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 109, "cm", "WEEK 2",
"01-101-1002", "WSTCIR", "Waist Circumference (cm)", 108, "cm", "WEEK 3"
)
derive_param_waisthgt(
advs,
by_vars = exprs(USUBJID, VISIT),
wstcir_code = "WSTCIR",
height_code = "HEIGHT",
set_values_to = exprs(
PARAMCD = "WAISTHGT",
PARAM = "Waist to Height Ratio"
),
get_unit_expr = admiral::extract_unit(PARAM)
)
# Example 4: Automatic conversion is performed when deriving the ratio
# if parameters are provided in different units (e.g. centimeters and inches)
advs <- tribble(
~USUBJID, ~PARAMCD, ~PARAM, ~AVAL, ~AVALU, ~VISIT,
"01-101-1001", "HEIGHT", "Height (cm)", 147, "cm", "SCREENING",
"01-101-1001", "WSTCIR", "Waist Circumference (in)", 39.37, "in", "SCREENING",
"01-101-1001", "WSTCIR", "Waist Circumference (in)", 38.98, "in", "WEEK 2",
"01-101-1001", "WSTCIR", "Waist Circumference (in)", 38.58, "in", "WEEK 3",
"01-101-1002", "HEIGHT", "Height (cm)", 163, "cm", "SCREENING",
"01-101-1002", "WSTCIR", "Waist Circumference (in)", 43.31, "in", "SCREENING",
"01-101-1002", "WSTCIR", "Waist Circumference (in)", 42.91, "in", "WEEK 2",
"01-101-1002", "WSTCIR", "Waist Circumference (in)", 42.52, "in", "WEEK 3"
)
derive_param_waisthgt(
advs,
by_vars = exprs(USUBJID, VISIT),
wstcir_code = "WSTCIR",
height_code = "HEIGHT",
set_values_to = exprs(
PARAMCD = "WAISTHGT",
PARAM = "Waist to Height Ratio"
),
constant_by_vars = exprs(USUBJID),
get_unit_expr = admiral::extract_unit(PARAM)
)