Time computations

Age, Reaction duration, Drug treatment duration and Time-To-Onset

These values are considered durations and are all calculated according to the same principles. If the actual value is not reported, a calculated duration from reported dates are shown.’

Duration	Start date	Stop date
Patient age	PatientBirthDate	ReactionStartDate*
Reaction duration	ReactionStartDate	ReactionEndDate
Drug treatment duration	DrugStartDate	DrugEndDate
Time-To-Onset	DrugStartDate	ReactionStartDate

*When several reactions with different start dates are reported within the same case, the earliest date is used.

Each date is given a min and a max value (down to minute), see examples below:

Date (reported)	Date min	Date max
2000	2000-01-01 00:00	2000-12-31 23:59
200001	2000-01-01 00:00	2000-01-31 23:59
20000101	2000-01-01 00:00	2000-01-01 23:59
2000010113	2000-01-01 13:00	2000-01-01 13:59
200001011334	2000-01-01 13:34	2000-01-01 13:34

Duration is calculated out of the min and the max dates and each duration is given a min, max and mean value.

Duration min is set to the time span between the highest possible start date and the lowest possible stop date (e.g. for Patient age it is ReactionStartDate min – PatientBirthDate max) Duration max is set to the time span between the lowest possible start date and the highest possible stop date (e.g. for Patient age it is ReactionStartDate max – PatientBirthDate min) Duration mean is set to (Duration min + Duration max) /2.

Durations are always rounded to nearest integer, except age which is rounded down. Duration mean is shown in VigiLyze, see examples below:

Start date - Stop date	Duration min	Duration max
200406-2006	1.5 years	2.6 years	2 years
20050506 – 2011	5.7 years	6.7 years	6 years
20130617-201309	2.5 months	3.4 months	3 months 2 months (if age)
19840108-19840111	2 days	4 days	3 days
19840108-19840108	-1 day	1 day	0 days
20090511-20090530	18 days	20 days	19 days
201103-2011	3 months	10 months	-*
2005-2005	-12 months	12 months	-*
200105-200105	-31 days	31 days	-*
20040903-200409	-3 days	28 days	-*

*If the uncertainty is high, i.e. difference between max and mean duration is more than 1.5, no duration is shown. This happens with incomplete dates that are close in time.