UK guidelines advise testing for latent tuberculosis infection (LTBI) in people with known HIV. Both National Institute for Health and Care Excellence (NICE) 2011 and 2016, and British HIV Association (BHIVA) guidelines use targeted testing, in comparison to those from other countries, notably the United States. None of these have been compared for cost-effectiveness in a contemporary HIV population.

We sought to determine the cost-effectiveness of each UK guideline from an NHS perspective, plus alternatives, using prospective data.

All patients with a new HIV diagnosis attending an ambulatory HIV clinic, plus a sample of those with known HIV were approached; and offered a symptom questionnaire, chest radiograph (CXR), tuberculin skin test (TST), blood interferon gamma release assay (IGRA) and induced sputum for mycobacterial culture (IS). The uptake and results were used to calculate the cost-effectiveness of thirty different testing strategies using univariate, multivariate and probabilistic sensitivity analyses (PSA).

219 subjects, representative of the total clinic population, took part. 73% were male, 28% black African and 95% on antiretroviral therapy (ART). During testing, 2 cases (0.9%) of subclinical TB and 14 (6%) of LTBI were detected. Half the patients with LTBI completed preventive treatment. Over a median of 28 months follow up, no new cases of active TB were identified.

When compared to no testing, only three of the thirty strategies were below the maximum NICE threshold for cost-effectiveness <£30,000/QALY gained. Testing black Africans with just TST or IGRA cost £23,429/QALY and £28,971/QALY respectively, whilst testing black Africans plus those from countries with a TB incidence of >20/100,000 (‘middle incidence’, MI) cost £25,218/QALY and £32,410/QALY using TST alone or IGRA alone respectively. NICE, BHIVA, or more extensive strategies, were not cost-effective. (Table)

Using PSA, no testing was most likely cost-effective up to £30,000/QALY.

In a contemporary HIV population with very high uptake of ART, neither current UK guideline is cost-effective. Testing black Africans, or black Africans and people from middle TB incidence countries appear at best marginally cost-effective. Future UK guidance needs to reflect changing health demographics, improved outcomes for people in HIV care, and clinical pragmatism.