Prevalence of subclinical pulmonary tuberculosis in adults in community settings: an individual participant data meta-analysis.

BACKGROUND: Subclinical pulmonary tuberculosis, which presents without recognisable symptoms, is frequently detected in community screening. However, the disease category is poorly clinically defined. We explored the prevalence of subclinical pulmonary tuberculosis according to different case definitions. METHODS: We did a one-stage individual participant data meta-analysis of nationally representative surveys that were conducted in countries with high incidence of tuberculosis between 2007 and 2020, that reported the prevalence of pulmonary tuberculosis based on chest x-ray and symptom screening in participants aged 15 years and older. Screening and diagnostic criteria were standardised across the surveys, and tuberculosis was defined by positive Mycobacterium tuberculosis sputum culture. We estimated proportions of subclinical tuberculosis for three case definitions: no persistent cough (ie, duration ≥2 weeks), no cough at all, and no symptoms (ie, absence of cough, fever, chest pain, night sweats, and weight loss), both unadjusted and adjusted for false-negative chest x-rays and uninterpretable culture results. FINDINGS: We identified 34 surveys, of which 31 were eligible. Individual participant data were obtained and included for 12 surveys (620 682 participants) across eight countries in Africa and four in Asia. Data on 602 863 participants were analysed, of whom 1944 had tuberculosis. The unadjusted proportion of subclinical tuberculosis was 59·1% (n=1149/1944; 95% CI 55·8-62·3) for no persistent cough and 39·8% (773/1944; 36·6-43·0) for no cough of any duration. The adjusted proportions were 82·8% (95% CI 78·6-86·6) for no persistent cough and 62·5% (56·6-68·7) for no cough at all. In a subset of four surveys, the proportion of participants with tuberculosis but without any symptoms was 20·3% (n=111/547; 95% CI 15·5-25·1) before adjustment and 27·7% (95% CI 21·0-36·4) after adjustment. Tuberculosis without cough, irrespective of its duration, was more frequent among women (no persistent cough: adjusted odds ratio 0·79, 95% CI 0·63-0·97; no cough: adjusted odds ratio 0·76, 95% CI 0·62-0·93). Among participants with tuberculosis, 29·1% (95% CI 25·2-33·3) of those without persistent cough and 23·1% (18·8-27·4) of those without any cough had positive smear examinations. INTERPRETATION: The majority of people in the community who have pulmonary tuberculosis do not report cough, a quarter report no tuberculosis-suggestive symptoms at all, and a quarter of those not reporting any cough have positive sputum smears, suggesting infectiousness. In high-incidence settings, subclinical tuberculosis could contribute considerably to the tuberculosis burden and to Mycobacterium tuberculosis transmission. FUNDING: Mr Willem Bakhuys Roozeboom Foundation.

Antituberculosis Drug Resistance Survey in Lesotho, 2008-2009: Lessons Learned.

SETTING: Drug resistance is an increasing threat to tuberculosis (TB) control worldwide. The World Health Organization advises monitoring for drug resistance, with either ongoing surveillance or periodic surveys. METHODS: The antituberculosis drug resistance survey was conducted in Lesotho in 2008-2009. Basic demographic and TB history information was collected from individuals with positive sputum smear results at 17 diagnostic facilities. Additional sputum sample was sent to the national TB reference laboratory for culture and drug susceptibility testing. RESULTS: Among 3441 eligible smear-positive persons, 1121 (32.6%) were not requested to submit sputum for culture. Among 2320 persons submitted sputum, 1164 (50.2%) were not asked for clinical information or did not have valid sputum samples for testing. In addition, 445/2320 (19.2%) were excluded from analysis because of other laboratory or data management reasons. Among 984/3441 (28.6%) persons who had data available for analysis, MDR-TB was present in 24/773 (3.1%) of new and 25/195 (12.8%) of retreatment TB cases. Logistical, operational and data management challenges affected survey results. CONCLUSION: MDR-TB is prevalent in Lesotho, but limitations reduced the reliability of our findings. Multiple lessons learned during this survey can be applied to improve the next drug resistance survey in Lesotho and other resource constrained countries may learn how to avoid these bottlenecks.

Preventing tuberculosis among HIV-infected pregnant women in Lesotho: the case for rolling out active case finding and isoniazid preventive therapy.

BACKGROUND: The Lesotho Ministry of Health issued guidelines on active case finding (ACF) for tuberculosis (TB) and isoniazid preventive therapy (IPT) in April 2011. ACF has been recommended in maternal and child health (MCH) settings globally, however, the feasibility of implementing IPT within MCH in countries with high concurrent HIV and TB epidemics is unknown. DESIGN/METHODS: The study evaluated the implementation of ACF and IPT guidelines in MCH settings in 2 health facilities in Lesotho. This descriptive prospective study analyzed data collected during routine services. Categorical data and continuous variables were summarized using descriptive statistics. The χ test or Wilcoxon rank-sum test was used to ascertain significant associations between categorical and continuous variables, respectively. RESULTS: Data from 160 HIV-positive and 640 HIV-negative women were reviewed. Within this study population, 99.8% of women were screened for TB, and 11.4% HIV-positive women compared with 2.3% HIV-negative women were reported to have symptoms of TB (P < 0.001). IPT was initiated in 124/158 (78.5%) HIV-positive pregnant women, 64.5% women completed a 6-month IPT regimen, 2 (1.6%) died of causes unrelated to IPT/TB, and 31.5% were lost to follow-up. Predictors of IPT initiation among HIV-positive women included gestational age at the first antenatal visit (unadjusted odds ratio, -0.93; 95% confidence interval: -0.88 to 0.98), and receipt of antiretroviral therapy for treatment rather than for prevention of mother-to-child transmission prophylaxis only (odds ratio, 4.59; 95% confidence interval: 1.32 to 15.93). CONCLUSIONS: Implementation of ACF and IPT is feasible within the MCH setting. Uptake of IPT during pregnancy among HIV-positive women was high, but with a high rate of loss to follow-up.