Centres participating in the UK CHIC Study provide electronic data on eligible patients annually. The study collates information that is routinely collected by a clinic as part of a patient's HIV care, no additional study specific data or visits are required.

Data collected include patient demographics, information on clinical events (AIDS diagnoses and deaths), the results of various laboratory tests (CD4/CD8 counts and percentages, HIV RNA levels and laboratory measures of drug toxicity), antiretroviral drug use (date of starting and stopping each drug) and hepatitis co-infection. The data are held in a secure integrated relational database. All data are pseudonymised and it is not possible to identify individual patients from the datasets that are provided to the co-ordinating centre. After data quality checks and cleaning, each of the centres' datasets are combined, and records thought to belong to the same individual attending different clinics are merged using computer programmes. A final dataset is prepared annually, and only data items relevant to specific agreed analyses are made available to study collaborators.

Data from the UK CHIC Study are linked to HIV drug resistance test data in the UK HIV Drug Resistance Database, to the UK Seroconverter Register (CASCADE), CHIPS, and to HIV surveillance data at Public Health England.