Dechallenge computation

In the section “Time-to-onset, dechallenge, rechallenge and causality of suspect and interacting drugs”, the information about dechallenge is computed from different data elements to get a quick overview. The action taken with the drug together with the reaction outcome are translated into Dechallenge performed (Yes/No/Unknown) and Reaction resolved/resolving (Yes/No/Unknown)

Dechallenge performed is set to

• yes, if the action taken with the drug is “Drug withdrawn” or “Dose reduced”

• no, if the action taken with the drug is “Dose increased” or “Dose not changed”

• unknown, if the action taken with the drug is “Unknown”

• blank, if the action taken with the drug is “Not applicable”

Reaction resolved/resolving is set to

• yes, if the outcome of the reaction is “recovered/resolved”, “recovering/resolving” or “recovered/resolved with sequelae”

• no, if the outcome of the reaction is “not recovered/not resolved” or “fatal”

• unknown, if the outcome of the reaction is “Unknown”

Reaction resolved/resolving is only set if there is a reported value for action taken with the drug.

If none of the above is true, then free text from the data element drug additional is used. This is mainly to capture dechallenge information from case reports where we know this is not reported within the structured fields but rather as specific text strings.

• When drug additional is “DECHALL POS” then Dechallenge performed is set to yes and Reaction resolved/resolving is set to yes

• When drug additional is “DECHALL NEG” then Dechallenge performed is set to yes and Reaction resolved/resolving is set to no

• When drug additional is “DECHALL RESULT UNK” then Dechallenge performed is set to yes and Reaction resolved/resolving is set to unknown