Download Title: The REACH study – Exploring patterns of Retention and

Title: The REACH study – Exploring patterns of Retention and Engagement Across specialised Care
services of HIV positive patients in the United Kingdom
Date of submission: March 2013
Proposed study team: Alison Evans, Fiona Burns, Caroline Sabin
Background
Retention in HIV care is vital for treatment success at both individual and population levels. Good
engagement is associated with improved adherence, virological and immunological outcomes and
survival.1 The proposed study is all the more timely in the current context of expanded HIV testing
and the development of treatment as a form of secondary HIV prevention. Innovative models of
care targeting early HIV identification must be complemented by strategies promoting long-term
integration into care.
Previous analysis of UK CHIC data has shown that 17.4% of HIV patients were potentially lost to
follow up2 and analysis of SOPHID data indicated that nearly 5% of patients disengage with HIV care
in any one-year and a further 4% are intermittent attendees.3 The proposed study will
systematically define the complex patterns of HIV outpatient attendance in the UK. Patterns of
attendance will be used to calculate the health and financial costs of disengaging or partially
disengaging with care and undertake exploratory work to inform the design of interventions to meet
the diverse needs of people living with HIV.
Aims of proposal
To examine HIV outpatient attendance patterns among people living with HIV, using data routinely
collected in the UK CHIC study and to identify predictive factors of disengagement with specialised
care services. The goal of our research is to develop intervention models to improve engagement in
care, to be tested in future studies.
Inclusion/exclusion criteria
All patients under care at a participating UK CHIC centre from 2000 onwards.
Planned analyses
Until recently, the database did not capture clinic visits from all participating clinics, thus CD4 counts
and viral loads have traditionally been used as surrogates of attendance. We will continue to use
CD4 counts and viral loads in addition to other routine blood tests as surrogates of attendance.
Where available, data on outpatient attendances will be used and will help to validate surrogate
markers.
Descriptive analysis
We will describe HIV care attendance patterns, including the proportion of patients who disengage
from care, the proportion who re-engage with care, the number of episodes of disengagement and
typical length of episodes of disengagement. We will compare attendance patterns by demographic
variables (age, gender, ethnicity, risk group).
Predictive modelling
We will use group-based trajectory modelling4 to identify clusters of individuals following similar,
distinctive progressions of attendance over time. Logistic regression analyses will be used to predict
the probability of an individual being within a particular group according to a particular set of risk
factors and to explore factors associated with delayed linkage. This strategy will provide a unique,
statistical snapshot of the key characteristics and behaviours of this complex population. We will
compare attendance patterns across the UK and highlight whether future explorative work is needed
beyond London clinics.
Variables required
Demographic (age, gender, ethnicity, risk group), clinical (prior AIDS, death), ART start/stop dates
and reasons for discontinuation, laboratory markers with dates (CD4 counts, viral loads, toxicity
markers), pregnancy.
Any assessment of feasibility required
None.
Possible limitations/issues that should be considered when interpreting the findings
Information on outpatient attendances is not provided by all clinics – analyses will use CD4 counts,
viral loads and other routine blood tests as surrogates of attendance. A sensitivity analysis will be
performed using data where outpatient attendances are available.
Proposed time scale for analysis
Next nine months to one year.
Resources required (eg statistical support, database management)
None.
References
1
Gardner EM, et al. The Spectrum of Engagement in HIV Care and its Relevance to Test-and-Treat
Strategies for Prevention of HIV Infection. Clinical Infectious Diseases. 2011;52(6):793–800.
2
Hill T, Bansi L, Sabin C, et al. Data linkage reduces loss to follow-up in an observational HIV cohort
study. Journal of Clinical Epidemiology. 2010;63:1101-9.
3
Rice BD, Delpech VC, et al. Loss to Follow-Up Among Adults Attending Human Immunodeficiency
Virus Services in England, Wales, and Northern Ireland. Sexually Transmitted Diseases. 2011;
38(8):685-90.
4
Nagin DS, Odgers CL. Group-Based Trajectory Modeling in Clinical Research. Annual Review of
Clinical Psychology. 2010;6:109-138.