Scientific Concept of the National Cohort (status ... - Nationale Kohorte

A.3.7.2 recontacting and tracking of study participants
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A.3 Study design
Personal identifying information such as name, date of birth, and address will be obtained
prior to the invitation process at baseline, will be checked at the study center during recruitment,
and recorded in a separate file. If not yet available, further information such as the
participants’ cellular telephone numbers and e-mail addresses will be collected. This information
may help to ensure that participants are not lost during follow-up.
During the follow-up period, participants will be informed about interesting developments
and results of the National Cohort by regular newsletters. These newsletters can also advise
participants to communicate any changes in contact details actively to the study center.
Every 2–3 years after the first visit in the study center, participants will be contacted by mail
or e-mail, including a follow-up questionnaire. For subjects who do not respond to the initial
follow-up questionnaire, a reminder letter will be sent. If a contact cannot be established by
these means, participants will be, where applicable, contacted by phone and a computerassisted
telephone interview will be offered at the same time or a later time scheduled. In
addition, if the subjects do not (for various reasons) want to answer the questionnaire, a
short version, assessing the health status related to the main diseases of interest, will be
asked, to enable the comparison of a few core characteristics of responders and nonresponders.
For all study subjects who do not respond to the follow-up procedure invitations (undelivered
mail/e-mail, no contact or response) an inquiry at the residents’ registration office will
be initiated that clarifies the vital status of the subject and whether subjects have moved
away (all residents in Germany are required to provide their the new address once they
move away).
In case of death, as the registries record the date and place of death, the date of death
(population registries) and cause of death (public health office) will be obtained.
For subjects who have moved, the new address will be obtained from the original registration
office.
In the study database, the tracking status for each study subject will therefore be regularly
updated. The most likely status is ”full participant” (has sent back a completed questionnaire).
The other final status categories are “dead”, “final drop out” (has left the study) or
“permanently unavailable” (e.g., no permanent residence, has moved to another country).
A.3.7.3 follow-up procedures for ascertainment of vital status and incident
diseases
Prospective ascertainment of incident diseases will primarily be based on active follow-up
procedures. These include the assessment of novel onset disease by means of questionnaires,
which will be verified, for defined diseases, by contacting the participant’s pertinent
physician(s).
Questionnaires will be sent to the participants every 2–3 years (see above) to request
information about any major, physician-diagnosed diseases that have occurred since the
baseline visit, including the treating physician and the date of diagnosis (see Table 3.15).
For certain diseases, we will also use additional information obtained via questionnaire
from the participant to increase the sensitivity of disease ascertainment (Table 3.15). For
example, to increase sensitivity to detect incident cases of type 2 diabetes, we will also
consider information on new onset of antidiabetic treatment.
A.3