The prevalence of pulmonary tuberculosis among miners from the Karonga, Rumphi, Kasungu and Lilongwe Districts of Malawi in 2019.

Introduction: Miners in sub-Saharan Africa have a greater risk of tuberculosis (TB) than any other working population in the world. In spite of the presence of large and vulnerable population of miners in Malawi, no previous study has aimed to assess the burden of TB among these miners. This study aimed to determine the prevalence of pulmonary tuberculosis (PTB) and health-seeking behaviour (HSB) in a population of miners in Malawi, and a range of associated factors. Our goal was to develop a method to identify missing cases of TB. Methods: We conducted a cross-sectional study in the Karonga, Rumphi, Kasungu and Lilongwe districts of Malawi in 2019. We calculated frequencies, proportions, odds ratios (ORs) and their 95% confidence intervals (95% CIs), and used the chi-square test in STATA version15.1 to investigate the burden and magnitude of PTB in the mining sector. Bivariate and multivariate logistic regression models were also fitted for PTB and HSB. Results: Of the 2400 miners approached, we were able to interview 2013 (84%). Of these, 1435 (71%) were males, 1438 (71%) had known HIV status and 272 (14%) had PTB. Multivariate analysis showed that the miners performing informal mining were 50% more likely to develop PTB compared with those in formal mining (adjusted odds ratio [AOR]=1.50, 95% CI: 1.10-2.05, P=0.01). A total of 459 (23% of 2013) miners had presumptive TB. Of these, 120 (26%) sought health care; 80% sought health care at health facilities. Multivariate analysis also showed that miners who experienced night sweats were less likely to seek health care compared with those without night sweats (AOR=0.52, 95% CI: 0.30-0.90, P=0.02). Conclusion: The prevalence of PTB was higher among miners than in the general population. Consequently, targeted TB screening programmes for miners may represent a suitable strategy to adopt if we are to end TB by 2030. Poor health-seeking behaviours among miners is worrisome and further qualitative research is necessary to understand the barriers to accessing health care in these settings.

Should Urine-LAM Tests Be Used in TB Symptomatic HIV-Positive Patients When No CD4 Count Is Available? A Prospective Observational Cohort Study From Malawi.

BACKGROUND: Current eligibility criteria for urine lateral-flow lipoarabinomannan assay (LF-LAM) in ambulatory, HIV-positive patients rely on the CD4 count. We investigated the diagnostic yield of LF-LAM and the 6-month mortality in ambulatory, TB symptomatic, HIV-positive patients regardless of their CD4 count. METHODS: We conducted a prospective, observational study that included all ambulatory, ≥15-year-old, TB symptomatic (cough, weight loss, fever, or night sweats) HIV-positive patients presenting at 4 health facilities in Malawi. Patients received a clinical examination and were requested urine LF-LAM, sputum microscopy, and Xpert MTB/RIF. TB was defined as bacteriologically confirmed if Xpert was positive. RESULTS: Of 485 patients included, 171 (35.3%) had a CD4 <200 and 32 (7.2%) were seriously ill. Median CD4 count was 341 cells/µL (interquartile range: 129-546). LAM was positive in 24.9% patients with CD4 < 200 (50% LAM grades 2-4) and 12.5% with CD4 ≥ 200 (12.8% LAM grades 2-4). Xpert was positive in 14.1% (44/312). Among Xpert-positive patients, LAM positivity was 56.7% (CD4 < 200) and 42.9% (CD4 ≥ 200), P = 0.393. Of the patients without an Xpert result, 13.4% (23/172) were LAM positive (ie, potentially missed patients). Overall, mortality was 9.2% (44/478). More pronounced LAM-positive patients had higher mortality than LAM-negative (grades 2-4: 36.0%; grade 1: 9.1%; negative: 7.4%; P < 0.001). LAM-positive patients with CD4 <200 cells/µL had higher risk of mortality than LAM negatives (adjusted hazard ratio: 3.2, 95% confidence interval: 1.4 to 7.2, P = 0.006), particularly those with LAM grades 2-4 (adjusted hazard ratio: 4.9, 95% confidence interval: 1.8 to 13.3, P = 0.002). CONCLUSIONS: Urine-LAM testing can be useful for TB diagnosis in HIV-positive TB-symptomatic patients with no CD4 cell count. LAM grade can identify patients at higher risk of death in this situation.

Risk of Mycobacterium tuberculosis transmission in an antiretroviral therapy clinic.

OBJECTIVE: The risk of transmission of Mycobacterium tuberculosis in antiretroviral therapy (ART) clinics is recognized, particularly, when HIV and tuberculosis services are unified, but the degree of potential exposure to patients with infectious tuberculosis has not been measured. We aimed to quantify this clinic exposure. METHODS: Over 1 year, we recorded all visits to a clinic in northern Malawi that offers HIV testing and counselling, HIV care, ART, and TB diagnostic and treatment services. We included patients and guardians, noting timing and reason for the visit, using a palm vein reader to assist recognition of individuals and record times automatically. Screening for tuberculosis was enhanced, including induced sputum if necessary. RESULTS: Information was collected on 5011 individuals and 19 426 visits. During the period, 90 individuals with bacteriologically confirmed pulmonary tuberculosis attended the clinic when they were likely to have been infectious (taken as 6 weeks before diagnosis to 2 weeks after the start of treatment), including 76 who attended before tuberculosis was diagnosed or suspected. We estimated that 19% of visits had at least 1 h of potential exposure to patients with infectious tuberculosis, half to patients attending prediagnosis. CONCLUSION: There was considerable risk of exposure, including of immunosuppressed patients, to patients with infectious tuberculosis, especially as repeated visits are made. Much of this exposure could not be avoided by separation of patients with known tuberculosis. Good ventilation and avoidance of crowding is essential to minimize transmission of M. tuberculosis in this type of setting.