measure_abstinence_period {CTNote} | R Documentation |
Measure the Length of the Longest Abstinent Period
Description
Find the longest number of sequential visits in the pattern with negative UDS
Usage
measure_abstinence_period(use_pattern_binary, use_is = "+")
Arguments
use_pattern_binary |
A character string showing the daily, by visit, or weekly substance use pattern for a single subject, recoded to binary use or abstinence indicators. |
use_is |
Which single character is used to mark positive UDS in the
use pattern string? Defaults to |
Details
The use pattern MUST be in binary code for this function to work.
For use patterns coded in our default language (see the "dictionary" in the
Details section for measure_retention
), the binary form would
have all "_" (missing by study protocol) visits replaced with "-" and all
"o" (missing for non-compliance) and "*" (mixed positive and negative)
visits replaced with "+". See the example below.
Value
An integer measuring the longest number of sequential visits for which the subject was abstinent from the substance(s) of interest. If the subject's entire use pattern is missing, then this will be 0.
Examples
pattern_char <- "__++++*o-------+--+-o-o-o+o+oooooo"
# replace "_" with "-"
pattern2_char <- recode_missing_visits(
pattern_char,
missing_is = "_",
missing_becomes = "-"
)
# replace "o" with "+"
pattern3_char <- recode_missing_visits(pattern2_char)
# replace "*" with "+"
pattern4_char <- recode_missing_visits(pattern3_char, missing_is = "*")
measure_abstinence_period(pattern4_char)