Contribution des diagnostics au points de service dans l’identification de la maladie à VIH avancée

BACKGROUND

Médecins Sans Frontières Belgium installed point-of-care (POC) diagnostics for the early detection of advanced HIV disease (AHD), and in its presence, TB and cryptococcosis, in six health centres (Kasai, St Ambroise, St Joseph, Libondi, Lisanga and Kimia) in Kinshasa, Democratic Republic of the Congo (DRC).

OBJECTIVE

To document their contribution to the diagnosis of these conditions.

METHOD

This is a retrospective cross-sectional study of HIV-positive adolescents and adults admitted with suspected AHD. A comparison 2 years before and 2 years after installation of POC was performed.

RESULTS

A total of 745 and 887 patients were included before and after POC, respectively. The mean age was 39.7 years (standard deviation [SD] 12.04); 66% (n = 1,077) were women. Patients with CD4 counts increased from 40.3% (n = 300) to 64.4% (n = 573) (P < 0.001). After the installation of POC, they ranged from 47.8% (Lisanga) to 97.1% (Kasai). The proportion of AHD was comparable (n = 158, 52.7% vs. n = 288, 50.3%; P = 0.779). Among patients with AHD, TB was detected in 28.5% (n = 82), of which 41.5% (n = 34) were confirmed; cryptococcosis was detected in 24.7% (n = 71), of which 9.9% (n = 7) were confirmed. Disparities between centres were observed.

CONCLUSION

The POCs have increased patient access to CD4 testing and diagnosis of AHD in the six centres in DRC. However, actions are required to improve this performance, including screening for TB and cryptococcosis.

TB testing in HIV-positive patients prior to antiretroviral treatment

BACKGROUND: TB diagnosis in patients with HIV is challenging due to the lower sensitivities across tests. Molecular tests are preferred and the Xpert^® MTB/RIF assay has limitations in lower-income settings. We evaluated the performance of loop-mediated isothermal amplification (LAMP) and the lipoarabinomannan (LAM) test in HIV-positive, ART-naïve clinic patients.METHODS: A total of 783 eligible patients were enrolled; three spot sputum samples of 646 patients were tested using TB-LAMP, Xpert, smear microscopy and culture, while 649 patients had TB-LAM testing. Sensitivity, specificity, and negative and positive predictive values were estimated with 95% confidence intervals.RESULTS: Sensitivities for smear microscopy, TB-LAMP and Xpert were respectively 50%, 63% and 74% compared to culture, with specificities of respectively 99.2%, 98.5% and 97.5%. An additional eight were positive on TB-LAM alone. Seventy TB patients (9%) were detected using standard-of-care testing, an additional 27 (3%) were detected using study testing. Treatment was initiated in 57/70 (81%) clinic patients, but only in 56% (57/97) of all those with positive TB tests; 4/8 multidrug-resistant samples were detected using Xpert.CONCLUSION: TB diagnostics continue to miss cases in this high-burden setting. TB-LAMP was more sensitive than smear microscopy, and if followed by culture and drug susceptibility testing as required, can diagnose TB in HIV-positive patients. TB-LAM is a useful add-in test and both tests at the point-of-care would maximise yield.