Comparison of screening strategies to improve the diagnosis of latent tuberculosis infection in the HIV-positive population: a cohort study
- Katrina M Pollock1,
- Herman Tam1,
- Lisa Grass1,
- Sharleen Bowes1,
- Graham S Cooke2,
- Manish Pareek1,
- Damien Montamat-Sicotte1,
- Moses Kapembwa3,
- Graham P Taylor2,
- Ajit Lalvani1
- 1Tuberculosis Research Unit, National Heart and Lung Institute, Imperial College London, London, UK
- 2Section of Infectious Diseases, Department of Medicine, Imperial College London, London, UK
- 3Department of Genitourinary and HIV medicine, Northwick Park Hospital, The North West London Hospitals NHS Trust, Middlesex, UK
- Correspondence to Dr Katrina Mary Pollock;
- Received 14 December 2011
- Accepted 23 January 2012
- Published 1 March 2012
Background HIV is the most important risk factor for progression of latent tuberculosis infection (LTBI) to active tuberculosis (TB). Detection and treatment of LTBI is necessary to reduce the increasing burden of TB in the UK, but a unified LTBI screening approach has not been adopted.
Objective To compare the effectiveness of a TB risk-focused approach to LTBI screening in the HIV-positive population against current UK National Institute for Health and Clinical Excellence (NICE) guidance.
Design Prospective cohort study.
Setting Two urban HIV treatment centres in London, UK.
Participants 114 HIV-infected individuals with defined TB risk factors were enrolled prospectively as part of ongoing studies into HIV and TB co-infection.
Outcome measures The yield and case detection rate of LTBI cases within the research study were compared with those generated by the NICE criteria.
Results 17/114 (14.9%, 95% CI 8.3 to 21.5) had evidence of LTBI. Limiting screening to those meeting NICE criteria for the general population (n=43) would have detected just over half of these, 9/43 (20.9%, 95% CI 8.3 to 33.5) and those meeting criteria for HIV co-infection (n=74) would only have captured 8/74(10.8%, 95% CI 3.6 to 18.1) cases. The case detection rates from the study and NICE approaches were not significantly different. LTBI was associated with the presence of multiple TB risk factors (p=0.002).
Conclusion Adoption of a TB risk-focused screening algorithm that does not use CD4 count stratification could prevent more cases of TB reactivation, without changing the case detection rate. These findings should be used to inform a large-scale study to create unified guidelines.
To cite: Pollock KM, Tam H, Grass L, et al. Comparison of screening strategies to improve the diagnosis of latent tuberculosis infection in the HIV-positive population: a cohort study. BMJ Open 2012;2:e000762. doi:10.1136/bmjopen-2011-000762
Contributors KMP designed the study, recruited participants, designed and performed the experiments, analysed the data and wrote the manuscript. LG recruited participants and analysed the data. HT analysed the data and wrote the manuscript. SB performed the experiments. MP analysed the data and wrote the manuscript. GSC recruited participants and wrote the manuscript. MK recruited participants. DM-S designed the experiments and provided comments on the manuscript. GPT designed the study and wrote the manuscript. AL designed the study, designed experiments and wrote the manuscript. AL is the guarantor of the study.
Funding This study was funded with a TB Funds Grant TB08/02 from the British Lung Foundation. The funding body was not involved in experimental design, recruitment of participants, experimental work, data analysis, writing the manuscript or manuscript submission.
Competing interests The ESAT-6/CFP-10 ELISpot was commercialised by an Oxford University spin-out company (Oxford Immunotec Ltd, Abingdon, UK) in which Oxford University and Professor Lalvani have a minority share of equity and entitlement to royalties.
Patient consent All patients provided written informed consent using ethically approved Tuberculosis Research Unit research tissue back consent forms.
Ethics approval Ethical approval for this study was obtained from St Mary's REC, 2nd Floor A Block, 50 Eastbourne Terrace, London W2 6LG (07/H0712/85). Signed informed consent was obtained from all participants.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All participants were assigned a unique anonymised study number and all data are stored under this study number. Data sharing: no additional data available.
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