HIV infection continues to be a major health concern although current
drug treatments, which are based on combinations of drugs, are generally
very effective and an increasing proportion or HIV-infected individuals
are living to older age. However, some individuals have a poor response
to treatment, largely due to an inability to tolerate their drugs, poor
adherence to therapy or the development of HIV strains that are resistant
to the drugs used.
As the HIV epidemic has increased in size, and mortality rates have
dropped, the HIV-infected population in the UK has become more diverse.
The UK CHIC Study makes it possible to conduct research using information
collected on different groups of people infected with HIV in the UK.
For example, older people now make up an increasing proportion of
those with HIV, and they can have different health-care requirements.
Also, the way that an individual's immune system responds to treatment
for HIV varies with age, and the UK CHIC study data will enable investigation
of the possible adverse effects of long-term drug treatment in an
older population that may have other non-HIV related health problems.
HIV infection may contribute to an increased risk of several serious
events that had previously been thought to be unrelated to HIV, including
certain cancers, cardiovascular disease and liver failure. Research
suggests that earlier treatment for HIV may have a greater impact
on mortality than previously anticipated, so there is likely to be
a move towards starting HIV treatment earlier. The drugs used and
the way that these drugs are combined have changed over time. One
of the key aims of the UK CHIC study is to use the data to monitor
the way people's health responds to drug treatment, both in those
that are new to taking ani-HIV drugs and in those who are already
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
and to HIV surveillance data at the Health
Members of the UK CHIC steering committee are encouraged to submit
research proposals for analyses using UK CHIC data. Our study outputs
are largely in the form of research presentations at national and
international meetings, followed by publications in peer-reviewed
journals. Summaries of published studies regularly appear in the
HIV community press.
The UK CHIC Study has received project grant support from the Medical
Research Council (MRC) from 2001 to 2014. In August 2014, the UK
CHIC Study and the UK HIV Drug Resistance Database (UK HDRD) were
jointly awarded a further 5 years of support from the MRC, enabling
the projects to continue until August 2019.