Characterizing the etiology of recurrent tuberculosis using whole genome sequencing-Alaska, USA, 2008-2020.

BACKGROUND: Understanding the etiology of recurrent tuberculosis (rTB) is important for effective TB control. Prior to the advent of whole genome sequencing (WGS), attributing rTB to relapse or reinfection using genetic information was complicated by the limited resolution of conventional genotyping methods. METHODS: We applied a systematic method of evaluating whole genome single nucleotide polymorphism (wgSNP) distances and results of phylogenetic analyses to characterize the etiology of rTB in American Indian and Alaska Native (AIAN) persons in Alaska during 2008-2020. We contextualized our findings through descriptive analyses of surveillance data and results of a literature search for investigations that characterized rTB etiology using WGS. RESULTS: The percentage of TB cases in AIAN persons in Alaska classified as recurrent episodes (11.8%) was three times the national percentage (3.9%). Of 38 recurrent episodes included in genetic analyses, we attributed 25 (65.8%) to reinfection based on wgSNP distances and phylogenetic analyses; this proportion was the highest among 16 published point estimates identified through the literature search. By comparison, we attributed 11 of 38 (28.9%) and 6 of 38 (15.8%) recurrent episodes to reinfection based on wgSNP distances alone and on conventional genotyping methods, respectively. CONCLUSIONS: WGS and attribution criteria involving genetic distances and patterns of relatedness can provide an effective means of elucidating rTB etiology. Our findings indicate that rTB occurs at high proportions among AIAN persons in Alaska and is frequently attributable to reinfection, reinforcing the importance of active surveillance and control measures to limit the spread of TB disease in Alaskan AIAN communities.

Recurrence Rate of Pulmonary Tuberculosis in Patients Treated with the Standard 6-Month Regimen: Findings and Implications from a Prospective Observational Multicenter Study.

Tuberculosis (TB) recurrence following successful treatment is a significant challenge in TB control programs. However, the rate of TB recurrence varies among studies. It depends on several factors, including the country/region where the investigation occurs, the study design, sample characteristics, and the anti-TB regimen used. In Yemen, a few previous studies examined the rate of TB recurrence and reported high recurrence rates, with a 5-year recurrence rate of approximately 9.5%. However, they were conducted before 2010 using the previous anti-TB regimen which was phased out and replaced with the World Health Organization's (WHO) standard 6-month TB regimen. Consequently, this study aimed to examine the rate of TB recurrence after the implementation of the WHO standard 6-month regimen in Yemen. A prospective observational study was conducted with patients diagnosed with drug-susceptible pulmonary TB. The patients were recruited from five health centers with TB units in five governorates from January to December 2011. All the patients were followed up for five years after treatment completion. A total of 439 patients who completed the anti-TB regimen met the inclusion criteria and were included in the study. During the 5-year follow-up period, 8 patients (1.8%) died, and 13 patients (2.96%) were lost to follow-up, resulting in a final cohort of 418 patients. Of the cohort, 50.5% (n = 211) were male, while 49.5% (n = 207) were female patients. Of the patients, 129 patients (30.9%) were illiterate, 56 (13.4%) had cavitary pulmonary disease, and 6.2% (n = 26) had diabetes. The overall 5-year rate of TB recurrence in this study for the patients receiving the standard 6-month regimen was 2.9% (12/418). Moreover, almost half of the recurrent cases (41.7%; n = 5) were seen during the first year of the follow-up period. Some patient groups with risk factors recorded a higher recurrence rate, including patients with diabetes (15.4%), non-compliant patients (14.3%), pre-treatment lung cavitation patients (8.9%), illiterate patients (7.8%), and underweight patients (5.1%). In conclusion, the overall TB recurrence rate with the standard 6-month regimen was lower than that with the previous TB regimens. However, more efforts are needed to decrease TB recurrence rates further and achieve a durable cure for TB. In addition, healthcare professionals and TB control programs should consider potential risk factors of recurrence and address them to provide optimal care.

Heightened Microbial Translocation Is a Prognostic Biomarker of Recurrent Tuberculosis.

BACKGROUND: Microbial translocation is a known characteristic of pulmonary tuberculosis (PTB). Whether microbial translocation is also a biomarker of recurrence in PTB is not known. METHODS: We examined the presence of microbial translocation in a cohort of newly diagnosed, sputum smear, and culture positive individuals with drug-sensitive PTB. Participants were followed up for a year following the end of anti-tuberculosis treatment. They were classified as cases (in the event of recurrence, n = 30) and compared to age and gender matched controls (in the event of successful, recurrence free cure; n = 51). Plasma samples were used to measure the circulating microbial translocation markers. All the enrolled study participants were treatment naïve, HIV negative and with or without diabetes mellitus. RESULTS: Baseline levels of lipopolysaccharide (LPS) (P = .0002), sCD14 (P = .0191), and LPS-binding protein (LBP) (P < .0001) were significantly higher in recurrence than controls and were associated with increased risk for recurrence, whereas intestinal fatty acid binding protein (I-FABP) and Endocab showed no association. Receiver operating characteristic (ROC) curve analysis demonstrated the utility of these individual microbial markers in discriminating recurrence from cure with high sensitivity, specificity, and area under the curve (AUC). CONCLUSIONS: Recurrence following microbiological cure in PTB is characterized by heightened baseline microbial translocation. These markers can be used as a rapid prognostic tool for predicting recurrence in PTB.

Correlation between ILC2 and Th17/Treg ratio in peripheral blood of patients at different stages of Mycobacterium tuberculosis infection / 中华微生物学和免疫学杂志

Objective:To study the correlation between type 2 innate lymphocyte (ILC2) and Treg/Th17 ratio in the peripheral blood of patients at different stages of Mycobacterium tuberculosis ( Mtb) infection. Methods:This study recruited 30 individuals with active tuberculosis (ATB group), 26 with treated tuberculosis (RTB group), 22 with latent tuberculosis infection (LTBI group) and 17 negative for tuberculin skin test (TST-negative group). Flow cytometry was used to detect the proportion of ILC2 in CD45 + cells, and that of Th17 and Treg cells in CD4 + T lymphocytes in the peripheral blood of patients in each group. Expression of Foxp3 and RORγt at mRNA level was detected by real-time fluorescence quantitative PCR. Pearson method was used to analyze the correlation between Th17 and Treg, and that between ILC2 and Treg/Th17 ratio in the peripheral blood of patients with ATB and RTB. Results:The proportions of ILC2 in RTB and ATB groups were significantly higher than those of LTBI and TST-negative groups, and the proportion of ILC2 in RTB group was significantly higher than that of ATB group ( P<0.05). The proportion of Th17 in RTB group was lower than that of ATB group ( P<0.05), and the proportions of Th17 in ATB and RTB groups were lower than those of LTBI and TST-negative groups. The proportion of Treg in RTB group was lower than that of ATB group ( P<0.05), and close to that of LTBI group and TST-negative group, but the Treg/Th17 ratios in ATB and RTB groups were higher than those of LTBI and TST-negative groups. There was no significant difference in Treg/Th17 ratio between ATB and RTB groups ( P>0.05). The expression of Foxp3 and RORγt at mRNA level and Foxp3/RORγt ratio changed accordingly. Meanwhile, there was no correlation between Th17 and Treg in ATB or RTB group ( r=0.023, P=0.444; r=0.428, P=0.150). There was a positive correlation between ILC2 and Treg/Th17 ratio in ATB group ( r=0.794, P=0.000), while no correlation was found between ILC2 and Treg/Th17 ratio in RTB group ( r=0.197, P=0.297). Conclusions:In this study, the proportion of ILC2 was increased in the peripheral blood of TB patients, and the proportion of ILC2 in RTB group was higher than that of ATB group. In RTB group, Th17 accounted for a low proportion in the peripheral blood and was involved in inflammatory reactions, while Tregs were not involved in inflammatory reactions, but might have a certain inhibitory effect in patients with ATB. Further studies found that Th17-involved inflammatory reactions were not regulated by Tregs. ILC2 was involved in Treg/Th17 imbalance in ATB patients, but not in RTB patients.

Risk factors for types of recurrent tuberculosis (reactivation versus reinfection): A global systematic review and meta-analysis.

BACKGROUND: The purpose of this meta-analysis (PROSPERO number: CRD42021243204) is to perform extensive and penetrating analyses on the risk factors associated with reactivation or reinfection. METHODS: We searched PubMed and Embase using search terms. Risk factors (including gender, length of time between first onset and recurrent diagnosis, extrapulmonary tuberculosis, sputum smear, pulmonary cavity, Beijing family strains, diabetes, HIV infection, history of imprisonment, and immigration) were analyzed. The pooled risk ratio (RR) and 95% confidence interval (CI) were calculated with STATA 15.1. Heterogeneity was evaluated by I2 and P values. RESULTS: The meta-analysis included 25 studies with a total of 1,477 recurrent patients. After subgroup analysis, sensitivity analysis, and testing for publication bias, it was concluded that time spanning less than two years (RR = 1.56, 95% CI: 1.33-1.85) was a risk factor for endogenous reactivation, whereas coinfection with HIV (RR = 0.72, 95% CI: 0.63-0.83), Beijing family genotype (RR = 0.46, 95% CI: 0.32-0.67), history of imprisonment (RR = 0.36, 95% CI: 0.16-0.81), and immigration (RR = 0.66, 95% CI: 0.53-0.82) were associated with exogenous reinfection. CONCLUSIONS: The recurrence interval is a risk factor for the endogenous reactivation of tuberculosis. Infection with Beijing family strains, coinfection with HIV, imprisonment, and immigration contribute to the risk of exogenous reinfection.

A Mycobacterium tuberculosis Specific IgG3 Signature of Recurrent Tuberculosis.

South Africa has the highest prevalence of HIV and tuberculosis (TB) co-infection globally. Recurrent TB, caused by relapse or reinfection, makes up the majority of TB cases in South Africa, and HIV infected individuals have a greater likelihood of developing recurrent TB. Given that TB remains a leading cause of death for HIV infected individuals, and correlates of TB recurrence protection/risk have yet to be defined, here we sought to understand the antibody associated mechanisms of recurrent TB by investigating the humoral response in a longitudinal cohort of HIV co-infected individuals previously treated for TB with and without recurrent disease during follow-up, in order to identify antibody correlates of protection between individuals who do not have recurrent TB and individuals who do. We used a high-throughput, "systems serology" approach to profile biophysical and functional characteristics of antibodies targeting antigens from Mycobacterium tuberculosis (Mtb). Differences in antibody profiles were noted between individuals with and without recurrent TB, albeit these differences were largely observed close to the time of re-diagnosis. Individuals with recurrent TB had decreased Mtb-antigen specific IgG3 titers, but not other IgG subclasses or IgA, compared to control individuals. These data point to a potential role for Mtb-specific IgG3 responses as biomarkers or direct mediators of protective immunity against Mtb recurrence.

Factors associated with diagnostic delay in recurrent TB.

BACKGROUND: Recurrent tuberculosis (TB) contributes to the burden of TB. The study was designed to explore the time of diagnostic delay and risk of delay in patients with recurrent TB in China. METHODS: A total of 13,334 patients with new and recurrent TB registered in Yulin a city in China were included. The Kaplan-Meier survival curve was employed to estimate the median delay time. The mixed-effects survival model was used to identify the correlates associated with diagnostic delay. The outcome of interest in the model was"being diagnosed". RESULTS: We found that 6.5% of cases with TB were attributed to recurrence. The median delay time of recurrent TB cases (73 days) was more than twice as long as that of new TB (35 days). Individuals with recurrent TB had a higher risk of diagnostic delay than new TB (HR, 0.5, 95%CI, 0.5-0.6). Factors associated with diagnostic delay differed between new TB and recurrent TB cases. Immigrants (HR, 0.5, 95%CI, 0.3-0.9), cases notified by way of recommendation (HR, 0.6, 95%CI, 0.4-0.9) and diagnosed at TB dispensary (HR, 0.4, 95%CI, 0.3-0.6) were associated with a higher risk of a longer delay for recurrent TB cases. CONCLUSIONS: The proportion of TB cases attributed to recurrence was high. Patients with recurrent TB had a longer delay time and a higher risk of diagnostic delay. Further interventions to improve diagnostic delay should focus on screening for TB in immigrants, improving public health services at the lowest healthcare level and update of TB diagnosis and management model.

A Moxifloxacin-based Regimen for the Treatment of Recurrent, Drug-sensitive Pulmonary Tuberculosis: An Open-label, Randomized, Controlled Trial.

BACKGROUND: The substitution of moxifloxacin for ethambutol produced promising results for improved tuberculosis treatment outcomes. METHODS: We conducted an open-label, randomized trial to test whether a moxifloxacin-containing treatment regimen was superior to the standard regimen for the treatment of recurrent tuberculosis. The primary and secondary outcomes were the sputum culture conversion rate at the end of 8 weeks and the proportion of participants with a favorable outcome, respectively. RESULTS: We enrolled 196 participants; 69.9% were male and 70.4% were co-infected with human immunodeficiency virus (HIV). There was no significant difference between the study groups in the proportion of patients achieving culture conversion at the end of 8 weeks (83.0% [moxifloxacin] vs 78.5% [control]; P = .463); however, the median time to culture conversion was significantly shorter (6.0 weeks, interquartile range [IQR] 4.0-8.3) in the moxifloxacin group than the control group (7.9 weeks, IQR 4.0- 11.4; P = .018). A favorable end-of-treatment outcome was reported in 86 participants (87.8%) in the moxifloxacin group and 93 participants (94.9%) in the control group, for an adjusted absolute risk difference of -5.5 (95% confidence interval -13.8 to 2.8; P = .193) percentage points. There were significantly higher proportions of participants with Grade 3 or 4 adverse events (43.9% [43/98] vs 25.5% [25/98]; P = .01) and serious adverse events (27.6% [27/98] vs 12.2% [12/98]; P = .012) in the moxifloxacin group. CONCLUSIONS: The replacement of ethambutol with moxifloxacin did not significantly improve either culture conversion rates at the end of 8 weeks or treatment success, and was associated with a higher incidence of adverse events. CLINICAL TRIALS REGISTRATION: NCT02114684.

High mortality during tuberculosis retreatment at a Ghanaian tertiary center: a retrospective cohort study.

INTRODUCTION: High mortality among individuals receiving retreatment for tuberculosis (RT-TB) persists, although reasons for these poor outcomes remain unclear. METHODS: We retrospectively reviewed 394 RT-TB patients diagnosed between January 2010 and June 2016 in Accra, Ghana. RESULTS: Of RT-TB patients, 161 (40.9%) were treated empirically (negative/absent smear, culture or Xpert), of whom 30.4% (49/161) had only extrapulmonary TB signs or symptoms. Mortality during treatment was 19.4%; 15-day mortality was 10.8%. In multivariable proportional hazards regression, living with HIV (aHR=2.69 [95 CI: 1.51, 4.80], p<0.01) and previous loss-to-follow up (aHR=8.27 (95 CI: 1.10, 62.25), p=0.04) were associated with mortality, while drug susceptibility testing (DST, aHR=0.36 (95 CI: 0.13, 1.01), p=0.052) was protective. Isoniazid resistance was observed in 40% (23/58 tested) and rifampin resistance in 19.1% (12/63 tested). CONCLUSION: High rates of extrapulmonary TB and smear/culture negative disease highlight the barriers to achieving DST-driven RT-TB regimens and the need for improved diagnostics. Our finding of poly-drug resistance in rifampin-susceptible cases supports access to comprehensive first line DST. Additionally, interventions to reduce mortality, especially in HIV co-infected RT-TB patients, are urgently needed.

Whole genome sequencing provides additional insights into recurrent tuberculosis classified as endogenous reactivation by IS6110 DNA fingerprinting.

Recurrent tuberculosis (TB) after successful TB treatment occurs due to endogenous reactivation (relapse) or exogenous reinfection. We revisited the conclusions of relapse in a high TB incidence setting that were drawn on the basis of IS6110 restriction fragment length polymorphism (RFLP) analysis in a large retrospective cohort study in suburban Cape Town, South Africa. Using whole genome sequencing (WGS), we undertook pair-wise genome comparison of Mycobacterium tuberculosis strains cultured from diagnostic sputum samples collected at the index and recurrent TB episode for 25 recurrent TB cases who had been classified as relapse based on identical DNA fingerprint patterns in the earlier study. We found that paired strain genome sequences were identical or showed minimal variant differences in 22 of 25 recurrent TB cases, consistent with relapse. One showed 20 variant differences, suggestive of exogenous reinfection. Two of the 25 had mixed infections, each with the index episode strain detected as the dominant strain at recurrence in one of these patients, the minority strain harboured drug-resistance conferring mutations (rpoB, katG). In conclusion, our study highlights the additional value of WGS for investigating recurrent TB in settings with high infection pressure and closely related circulating strains, where the extent of re- and mixed infection may be underestimated.

Urban-rural disparities in treatment outcomes among recurrent TB cases in Southern Province, Zambia.

BACKGROUND: At least 13-20% of all Tuberculosis (TB) cases are recurrent TB. Recurrent TB has critical public health importance because recurrent TB patients have high risk of Multi-Drug Resistant TB (MDR-TB). It is critical to understand variations in the prevalence and treatment outcomes of recurrent TB between different geographical settings. The objective of our study was to estimate the prevalence of recurrent TB among TB cases and compare risk of unfavorable treatment outcomes between rural and urban settings. METHODS: In a retrospective cohort study conducted in southern province of Zambia, we used mixed effects logistic regression to asses associations between explanatory and outcome variables. Primary outcome was all-cause mortality and exposure was setting (rural/urban). Data was abstracted from the facility TB registers. RESULTS: Overall 3566 recurrent TB cases were diagnosed among 25,533 TB patients. The prevalence of recurrent TB was 15.3% (95% CI: 14.8 15.9) in urban and 11.3% (95% CI: 10.7 12.0) in rural areas. Death occurred in 197 (5.5%), 103 (2.9%) were lost to follow-up, and 113 (3.2%) failed treatment. Rural settings had 70% higher risk of death (adjusted OR: 1.7; 95% CI: 1.2 2.7). Risk of lost to follow-up was twice higher in rural than urban (adjusted OR: 2.0 95% CI: 1.3 3.0). Compared to HIV-uninfected, HIV-infected individuals on Antiretroviral Treatment (ART) were 70% more likely to die (adjusted OR: 1.7; 95% CI: 1.2 3.1). CONCLUSION: Recurrent TB prevalence was generally high in both urban and rural settings. The risk of mortality and lost to follow-up was higher among rural patients. We recommend a well-organized Directly Observed Therapy strategy adapted to setting where heightened TB control activities are focused on areas with poor treatment outcomes.

Distinct clinical characteristics and helminth co-infections in adult tuberculosis patients from urban compared to rural Tanzania.

BACKGROUND: Differences in rural and urban settings could account for distinct characteristics in the epidemiology of tuberculosis (TB). We comparatively studied epidemiological features of TB and helminth co-infections in adult patients from rural and urban settings of Tanzania. METHODS: Adult patients (≥ 18 years) with microbiologically confirmed pulmonary TB were consecutively enrolled into two cohorts in Dar es Salaam, with ~ 4.4 million inhabitants (urban), and Ifakara in the sparsely populated Kilombero District with ~ 400 000 inhabitants (rural). Clinical data were obtained at recruitment. Stool and urine samples were subjected to diagnose helminthiases using Kato-Katz, Baermann, urine filtration, and circulating cathodic antigen tests. Differences between groups were assessed by χ2, Fisher's exact, and Wilcoxon rank sum tests. Logistic regression models were used to determine associations. RESULTS: Between August 2015 and February 2017, 668 patients were enrolled, 460 (68.9%) at the urban and 208 (31.1%) at the rural site. Median patient age was 35 years (interquartile range [IQR]: 27-41.5 years), and 454 (68%) were males. Patients from the rural setting were older (median age 37 years vs. 34 years, P = 0.003), had a lower median body mass index (17.5 kg/m2 vs. 18.5 kg/m2, P <  0.001), a higher proportion of recurrent TB cases (9% vs. 1%, P <  0.001), and in HIV/TB co-infected patients a lower median CD4 cell counts (147 cells/µl vs. 249 cells/µl, P = 0.02) compared to those from urban Tanzania. There was no significant difference in frequencies of HIV infection, diabetes mellitus, and haemoglobin concentration levels between the two settings. The overall prevalence of helminth co-infections was 22.9% (95% confidence interval [CI]: 20.4-27.0%). The significantly higher prevalence of helminth infections at the urban site (25.7% vs. 17.3%, P = 0.018) was predominantly driven by Strongyloides stercoralis (17.0% vs. 4.8%, P <  0.001) and Schistosoma mansoni infection (4.1% vs. 16.4%, P <  0.001). Recurrent TB was associated with living in a rural setting (adjusted odds ratio [aOR]: 3.97, 95% CI: 1.16-13.67) and increasing age (aOR: 1.06, 95% CI: 1.02-1.10). CONCLUSIONS: Clinical characteristics and helminth co-infections pattern differ in TB patients in urban and rural Tanzania. The differences underline the need for setting-specific, tailored public health interventions to improve clinical management of TB and comorbidities.

Alternation of Gut Microbiota in Patients with Pulmonary Tuberculosis.

One-third of the world's population has been infected with Mycobacterium tuberculosis (M. tuberculosis), a primary pathogen of the mammalian respiratory system, while about 10% of latent infections progress to active tuberculosis (TB), indicating that host and environmental factors may determine the outcomes such as infection clearance/persistence and treatment prognosis. The gut microbiota is essential for development of host immunity, defense, nutrition and metabolic homeostasis. Thus, the pattern of gut microbiota may contribute to M. tuberculosis infection and prognosis. In current study we characterized the differences in gut bacterial communities in new tuberculosis patients (NTB), recurrent tuberculosis patients (RTB), and healthy control. The abundance-based coverage estimator (ACE) showed the diversity index of the gut microbiota in the patients with recurrent tuberculosis was increased significantly compared with healthy controls (p < 0.05). At the phyla level, Actinobacteria and Proteobacteria, which contain many pathogenic species, were significantly enriched in the feces RTB patients. Conversely, phylum Bacteroidetes, containing a variety of beneficial commensal organisms, was reduced in the patients with the recurrent tuberculosis compared to healthy controls. The Gram-negative genus Prevotella of oral origin from phylum of Bacteroidetes and genus Lachnospira from phylum of Firmicutes were significantly decreased in both the new and recurrent TB patient groups, compared with the healthy control group (p < 0.05). We also found that there was a positive correlation between the gut microbiota and peripheral CD4+ T cell counts in the patients. This study, for the first time, showed associations between gut microbiota with tuberculosis and its clinical outcomes. Maintaining eubiosis, namely homeostasis of gut microbiota, may be beneficial for host recovery and prevention of recurrence of M. tuberculosis infection.

Adolescent with recurrent tuberculosis: Can it be chronic granulomatous disease?

Chronic granulomatous disease (CGD) is an inherited primary immunodeficiency disorder with recurrent bacterial and fungal infections like Staphylococcus aureus, Nocardia spp, Serratia marcescens, Burkholderia cepacia, Salmonella spp. and Aspergillus species. We present a 13-year-old male child who had 3 episodes of tuberculosis (TB) at 5 years, 8 years and 13 years of age, respectively, with no other intercurrent infections and who was diagnosed as CGD at the age of 13 years. This case highlights the possibility of phenotypic variations of CGD. The diagnosis of CGD should also be sought in all children with recurrent TB.

Level of understanding of co-trimoxazole use among HIV infected, recurrent pulmonary tuberculosis suspects at a national referral tuberculosis clinic in Kampala, Uganda: a qualitative analysis.

BACKGROUND: Co-trimoxazole use is the standard of care for preventing Pneumocystis jirovecii pneumonia in sub-Saharan Africa but implementation remains slow. Co-trimoxazole is self- administered with uncertain adherence. Knowledge of co-trimoxazole use among HIV infected persons is unknown. OBJECTIVES: To assess knowledge, attitudes and practices of co-trimoxazole use among HIV infected adults evaluated for recurrent PTB in Kampala, Uganda. METHODS: A qualitative study utilizing 5 focus group discussions among 30 HIV infected PTB suspects at the national referral tuberculosis treatment centre in Kampala. RESULTS: Males and females had similar median ages. 80% were currently on co-trimoxazole and 50% of participants were on HAART. Majority of participants defined co-trimoxazole as an analgesic. Few noted co-trimoxazole was a drug to treat cough and chest pain. However, few responses revealed that co-trimoxazole prevents opportunistic diseases among PLHIV. Most of participants believed HAART and anti-TB drugs work as co-trimoxazole thus it should not be taken together with them. This belief may lead to increased risk of opportunistic infections, morbidity and mortality. CONCLUSIONS: We revealed gaps in understanding of co-trimoxazole use among study participants. We therefore recommend that more facts about co-trimoxazle as prophylaxis against P. jirovecii, bacterial and diarrheal pathogens should be incorporated in VCT fact sheets.

Prevalence of extended treatment in pulmonary tuberculosis patients receiving first-line therapy and its association with recurrent tuberculosis in Beijing, China.

BACKGROUND: In China, it is known that extended treatment is given to patients with pulmonary TB after they have successfully completed 6 months of first-line treatment. This practice is not officially reported to the National Tuberculosis Control Programme, so there are no data on its prevalence, its possible benefits in terms of preventing recurrent disease or the costs. This study aimed to provide information, from a single TB dispensary in Beijing, China, on the prevalence of extended anti-TB treatment and its relationship with recurrent TB. METHODS: Retrospective cohort study using the electronic national TB information system and dispensary medical records. RESULTS: Of 935 patients with pulmonary TB who completed 6-7 months of first-line drug treatment, 399 (43%) were given extended treatment. This was more common in patients with smear-positive disease, and those with lung cavities and more extensive radiographic lobar involvement at the time of diagnosis. Over 3-4 years' follow-up, recurrent disease was not significantly different in patients who received extended treatment (2.8%, 11/399) as compared to those who received the standard 6-month treatment (3.7%, 20/534). The median length of extended treatment was 89 days at a median cost of US$111 for drugs and US$32 for laboratory examinations. CONCLUSIONS: This study shows that extended treatment is common in one TB dispensary in Beijing. Further studies are needed to determine the countrywide prevalence of this practice and ascertain more conclusively the apparent lack of benefit.