The GP practice data set included: personal identifier for data linkage - forename, surname, date of birth, NHS number and postcode; demographic information: gender, ethnicity, registered date; and postcode to map to the Index of Multiple Deprivation (IMD) [ 16] using Geographical Information System GISS) methods.
Investigators did not send any personal identifier with data, but only identification codes.
In the current study, we used two databases, both containing the personal identifier and data on residency.
Confidentiality was assured by avoiding personal identifier of the data and the data was kept in a secure place by the principal investigator.
This study used public data from the NHIC, the Korea Health Panel and the NSO which do not have personal identifiers, and data publishing was approved by each organization's ethics committee.
11 Specifically, Statistics Denmark irreversibly encrypts personal identifiers, allows data access only through its own servers, and restricts statistical output to aggregate tables.
The patient's central registration system number, a unique personal identifier, allows for data linkage to other registries such as the Danish National Patient Registry.
In the present LIBE amendment, personal data is defined as data that contains a unique personal identifier (direct identification) or data that can be attributed to a person without the presence of an identifier because of the richness of the available information.
Postrandomisation, all participants are ascribed a unique personal identifier to anonymise the data.
Data are collected anonymously on standard questionnaires, using study serial numbers, without personal identifiers (linked anonymous data).
