Tuberculosis infection among close contacts of patients with pulmonary tuberculosis in China: a population-based, multicentered study.

OBJECTIVES: Limited information is currently available on the prevalence of and risk factors for tuberculosis infection (TBI) among close contacts of patients with pulmonary TB (PTB) in China. In this study, we estimated the burden of TBI among close contacts using QuantiFERON-TB Gold In-Tube assay (QFT) and identified factors associated with TB transmission among this high-risk population. METHODS: From January 1, 2018 to August 31, 2020, we identified laboratory-confirmed patients with PTB from a population-based, multicentered, cluster-randomized control trial for tuberculosis preventive treatment. Close contacts of these patients were identified, interviewed, and tested using the QFT assay. We estimated TBI prevalence and calculated ORs and 95% CIs for TBI risk factors. RESULTS: A total of 3138 index cases and 8117 close contacts were identified. Of these contacts, 36 had PTB (a prevalence of 443.51 cases/100 000 population). Among the remaining 7986 close contacts; 3124 (39.12%) reported a positive QFT result. QFT positivity was significantly associated with older age (adjusted OR, 1.77; [95% CI, 1.27-2.47], 2.20; [95% CI, 1.59-3.05], and 2.74; [95% CI, 1.96-3.82]) for age groups: 35-44, 45-54, and 55-64, respectively) when compared with a younger age group: 5-14; longer contact duration (adjusted OR, 1.44; 95% CI, 1.22-1.69); and sharing of a bedroom (adjusted OR, 1.39; 95% CI, 1.18-1.65). DISCUSSION: Our findings indicate a high TBI burden among the close contacts of PTB. The results also highlighted that contact tracing and investigation for TBI are necessary and beneficial, particularly for those who are older, have had a longer contact duration, and share a bedroom.

A community-based cross-sectional study of dietary composition and associated factors among tuberculosis patients in China.

To determine the dietary structure and its associated factors of tuberculosis (TB) patients in the community. This cross-sectional study analysed the dietary intake of 300 TB patients in two impoverished counties in China. Food intake was collected by using food frequency and two consecutive 24-h dietary review (24hdr) methods. The dietary composition and dietary structure of TB patients were compared with China's 2022 Dietary Reference Intake (DRIs) and the average reference value of dietary composition (ARC) in China in 2013. Binary logistic regression models were used to explore the factors associated with inadequate intake of animal food, insufficient protein and fat energy supply in patients with TB. The daily intake of various foods in TB patients was measured and the results were as follows: staple foods-median 372.12 g (interquartile range [IQR] 315.87 g); vegetables-median 200.00 g (IQR 205.55 g); fruits-median 20.22 g (IQR 36.82 g); animal foods-median 100.82 g (IQR 180.74 g); dairy products-median 0.00 g (IQR 0.00 g); nuts-median 17.10 g (IQR 29.75 g). The average daily intakes of vegetables, fruits, animal food, dairy products, soy and nuts were lower than those recommended by the DRIs (P < 0.01). Compared to women, men consumed more whole grains and mixed legumes, but less fruit. The dietary structures, including food and nutrient supply for energy, protein and fat, were significantly different in 300 patients compared with DRIs or ARC values. Inadequate rates of animal food intake were observed in 54.85% of men and 59.57% of women. Protein undersupply rates were 66.02% in men and 56.38% in women, while fat undersupply rates were 52.91% in men and 52.13% in women. The study revealed that being 18-49 years old, being the Han nationality, having less than 2 h of physical activity per day on average, and eating twice a day were risk factors for inadequate animal protein intake, protein energy deficiency and fat energy deficiency. TB patients from impoverished counties in China have inadequate intake of several food categories and insufficient protein and fat energy supply, correlating with multiple factors in socio-demographics, behavioral practices, and TB disease. To improve the nutritional status of TB patients, urgent public health actions, especially carrying out nutritional screening and evaluation once diagnosed, developing individualized nutritional support treatment plans, strengthening dietary nutritional health education and intervention, and advocating for enhanced nutritional support, should be taken.

Implementing a continuous quality-improvement framework for tuberculosis infection prevention and control in healthcare facilities in China, 2017-2019.

BACKGROUND: Tuberculosis (TB) infection prevention and control (IPC) in healthcare facilities is key to reducing transmission risk. A framework for systematically improving TB IPC through training and mentorship was implemented in 9 healthcare facilities in China from 2017 to 2019. METHODS: Facilities conducted standardized TB IPC assessments at baseline and quarterly thereafter for 18 months. Facility-based performance was assessed using quantifiable indicators for IPC core components and administrative, environmental, and respiratory protection controls, and as a composite of all control types We calculated the percentage changes in scores over time and differences by IPC control type and facility characteristics. RESULTS: Scores for IPC core components increased by 72% during follow-up when averaged across facilities. The percentage changes for administrative, environmental, and respiratory protection controls were 39%, 46%, and 30%, respectively. Composite scores were 45% higher after the intervention. Overall, scores increased most during the first 6 months. There was no association between IPC implementation and provincial economic development or volume of TB services. CONCLUSIONS: TB IPC policies and practices showed most improvement early during implementation and did not differ consistently by facility characteristics. The training component of the project helped increase the capacity of healthcare professionals to manage TB transmission risks. Lessons learned here will inform national TB IPC guidance.

Prevalence, Incidence, and Characteristics of Tuberculosis Among Known Diabetes Patients - A Prospective Cohort Study in 10 Sites, 2013-2015.

What is already known about this topic?: The association of diabetes mellitus (DM) with both increased risk of tuberculosis (TB) and unfavorable treatment outcomes has been identified by many studies (1). However, epidemic data for TB cases in DM patients is absent in China. What is added by this report?: This current population-based prospective cohort study, conducted in ten counties located in eastern, central, and western China during 2013-2015, revealed a high prevalence and incidence of TB in known DM patients. Most TB cases were captured by active case-finding and a much higher presence of being asymptomatic among TB/DM patients was obtained. What are the implications for public health practice?: Active case-finding should be carried out in DM patients and populations at high risk for developing TB. A TB symptom screening-based case-finding strategy is not enough; chest radiography check should be done once a year for these patients.

Comparison of yield and relative costs of different screening algorithms for tuberculosis in active case-finding: a cross-section study.

BACKGROUND: Part of tuberculosis (TB) patients were missed if symptomatic screening was based on the main TB likely symptoms. This study conducted to compare the yield and relative costs of different TB screening algorithms in active case-finding in the whole population in China. METHODS: The study population was screened based on the TB likely symptoms through a face-to-face interview in selected 27 communities from 10 counties of 10 provinces in China. If the individuals had any of the enhanced TB likely symptoms, both chest X-ray and sputum tests were carried out for them furtherly. We used the McNemar test to analyze the difference in TB detection among four algorithms in active case-finding. Of four algorithms, two were from WHO recommendations including 1a/1c, one from China National Tuberculosis Program, and one from this study with the enhanced TB likely symptoms. Furthermore, a two-way ANOVA analysis was performed to analyze the cost difference in the performance of active case-finding adjusted by different demographic and health characteristics among different algorithms. RESULTS: Algorithm with the enhanced TB likely symptoms defined in this study could increase the yield of TB detection in active case-finding, compared with algorithms recommended by WHO (p < 0.01, Kappa 95% CI: 0. 93-0.99) and China NTP (p = 0.03, Kappa 95% CI: 0.96-1.00). There was a significant difference in the total costs among different three algorithms WHO 1c/2/3 (F = 59.13, p < 0.01). No significant difference in the average costs for one active TB case screened and diagnosed through the process among Algorithms 1c/2/3 was evident (F = 2.78, p = 0.07). The average costs for one bacteriological positive case through algorithm WHO 1a was about two times as much as the costs for one active TB case through algorithms WHO 1c/2/3. CONCLUSIONS: Active case-finding based on the enhanced symptom screening is meaningful for TB case-finding and it could identify more active TB cases in time. The findings indicated that this enhanced screening approach cost more compared to algorithms recommend by WHO and China NTP, but the increased yield resulted in comparative costs per patient. And it cost much more that only smear/bacteriological-positive TB cases are screened in active case-finding.

Incidence and risk factors of tuberculosis among the elderly population in China: a prospective cohort study.

BACKGROUND: China is facing challenges of the shifting presentation of tuberculosis (TB) from younger to elderly due to an ageing population, longer life expectancy and reactivation disease. However, the burden of elderly TB and influence factors are not yet clear. To fill the gap, we generated a cohort study to measure the magnitude of TB incidence and associated factors among the elderly population aged 65 years and above in China. METHODS: In this cohort established in 2013 through a prevalence survey conducted in selected sites, a total of 34 076 elderlies without TB were enrolled into two-year follow-up. We used both active and passive case findings to find out all TB patients among them. The person-year (PY) incidence rates for both bacteriologically positive TB and active TB were calculated. Cox proportional regression model was performed to test effect of risk factors, and the population attributable fraction (PAF) of each risk factor contributing to incident TB among elderlies was calculated. RESULTS: Over the two-year follow-up period, a total of 215 incident active TB were identified, 62 of which were bacteriologically positive. The incidence rates for active TB and bacteriologically positive TB were 481.8 per 100 000 PY (95% CI: 417.4-546.2 per 100 000 PY) and 138.9 per 100 000 PY (95% CI: 104.4-173.5 per 100 000 PY), respectively. Incident cases detected by active case finding were significantly higher (P < 0.001). Male, non-Han nationality, previously treated TB, ex/current smoker and body mass index (BMI) < 18.5 presented as independent predictors for developing TB disease. For developing bacteriologically positive TB, the biggest contribution was from self-reported ex or current smoker (18.06%). And, for developing active TB, the biggest contribution was from non-Han nationality (35.40%), followed by male (26.80%) and age at 75 years and above (10.85%). CONCLUSIONS: Ageing population in China had a high TB incidence rate and risk to develop TB disease, implying that National TB Program (NTP) needs to prioritize for elderly. Active case finding should be applied capture more active TB cases among this particular population, especially for male, non-Han nationality, and those with identified risk factors.

A Tuberculosis Outbreak at a School - Xinjiang Uygur Autonomous Region, China, 2019.

WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Worldwide, tuberculosis (TB) continues to be the most important cause of death from a single infectious agent, and China has a high TB burden. Although the reported incidence of TB in students is lower than that in general population, TB outbreaks in schools have continuously been reported in the past years, suggesting that schools are a high-risk setting for TB transmission. WHAT IS ADDED BY THIS REPORT?: In total, 31 TB patients were founded in students. Epidemiological linkage among all TB cases could not be determined due to absence of genome sequencing. However, based on the analysis of screening results, the index case was probably the source of transmission. WHAT ARE THE IMPLICATIONS FOR PUBLIC HEALTH PRACTICE?: The preventative measurements should be implemented in schools. Adding TB examinations into entrance examinations and strengthening health education could find TB cases early, and improving ventilation could decrease the risk of TB transmission in schools.

Attrition and delays before treatment initiation among patients with MDR-TB in China (2006-13): Magnitude and risk factors.

BACKGROUND: China's national tuberculosis programme does not have cohort wise information regarding attrition and delays in the multidrug resistant tuberculosis (MDR-TB) diagnosis and treatment pathway. OBJECTIVE: Under the Global Fund programmatic management of drug-resistant TB (2006-13), we assessed the attrition and delay in the pathway and the factors associated. METHODS: Cohort study involving secondary programme data. All patients identified as presumptive MDR-TB (defined as i) previously treated TB patients which included recurrent TB, return after loss to follow up, treatment after failure and ii) new TB patients that were non-converters at three months of treatment or in close contact with a known MDR-TB patient) during October 2006 to June 2013 were eligible for phenotypic drug susceptibility testing (DST). Pre-diagnosis attrition (presumptive MDR-TB not undergoing culture and DST) and pre-treatment attrition (confirmed MDR-TB patients not initiated on treatment) was calculated. Diagnosis delay was the time interval from DST eligibility to DST result, treatment initiation delay was fom DST result to treatment initiation and total delay was from DST eligbility to treatment initiation. Factors associated with attrition and delay were identified using log binomial regression and linear regression, respectively. RESULTS: Of 78 564 presumptive MDR-TB patients, 2 470 (3.1%) underwent pre-diagnosis attrition. Of 9 283 MDR-TB patients, 3 361 (36.2%) underwent pre-treatment attrition. Median(IQR) diagnosis delay was 84 (64, 114) days; treatment initation delay was 23(6,68) days and total delay was 117(77,187) days. Long diagnosis delay was an independent predictor of pre-treatment attrition in a dose response relationship. While pre-treatment attrition was less likely among presumptive criterion 'previously treated' and with increasing time period, it was more likey among elderly and in east and west region. While the diagnosis delay increased with time period, treatment initiation delay and total delay reduced with time period. Short diagnosis delay was associated with west region, smear negative patients and presumptive criterion 'treatment after lost to follow up'. Short treatment initiation delay was associatied with east and west regions while long treatment initiation delay was associated with elderly and presumptive criterion 'recurrent TB'. Total delay predictors were similar to treatment initiation delay. In addition, short total delay was associated with presumptive criterion 'treatment after failure'. CONCLUSION: The diagnosis and treatment delay were long and the pre-treatment attrition was considerable high. Long diagnosis delay is likely to predict pre-treatment attrition.

Findings from a pilot project to assess the feasibility of active tuberculosis case finding among seniors in rural Sichuan Province, China, 2017.

BACKGROUND: China has a substantial tuberculosis (TB) disease burden and an aging population. Seniors have a higher risk of developing TB disease compared to younger age groups. Active case finding (ACF) could help identify seniors with TB disease. METHODS: From March to June 2017, we included ACF during annual physical check-ups for persons aged ≥ 65 years in Bayi, Sichuan Province. Seniors with clinical TB symptoms (i.e., cough lasting ≥ 2 weeks and/or hemoptysis) or one or more risk factors (e.g., previous TB disease, diabetes, and heavy alcohol consumption) were offered chest x-rays. We used acid-Fast Bacilli smear and solid culture laboratory testing for TB confirmation. We calculated the yield (i.e., cases identified among seniors screened) and cost per new each TB case detected. Focus group-interviews were conducted with health care workers and seniors to evaluate project acceptability. Participation rates and acceptability were used to assess feasibility. RESULTS: Of the 2,393 seniors residing in Bayi, 2,049 (85.6%) were enrolled in the pilot project. Of these seniors, 794 (38.7%) presented with at least one TB risk factor and 74 (3.6%) had symptoms consistent with active TB disease. Three seniors (0.2%)-each presenting with at least one risk factor-were diagnosed with active TB. The project yielded 146 TB cases per 100,000 seniors screened; the cost per case detected was $4,897. Most workers supported ACF if additional resources and staff could be provided. Seniors appreciated the convenience of this integrated health service approach. CONCLUSIONS: Although the yield was lower than expected, ACF appeared feasible in Bayi. Targeting seniors with at least one known TB risk factor could help detect previously unidentified TB cases. However, similar projects in communities with a higher TB prevalence are needed to further evaluate the yield and required resources prior to implementation on a larger scale. Findings from our pilot project should be combined with data from these future ACF projects to improve TB screening criteria.

Prevalence and risk factors of active pulmonary tuberculosis among elderly people in China: a population based cross-sectional study.

BACKGROUND: The problem of population aging is a critical public health concern in modern China, and more tuberculosis (TB) control efforts are needed to reach elderly people at high priority. In this study, we aim to determine the prevalence and identify the risk factors of TB among elderly people in China. METHODS: A multistage cluster-sampled cross-sectional survey was conducted in 2013, and 27 clusters were selected from 10 counties of 10 provinces in China. All consenting participants greater than or equal to 65 years of age were screened for pulmonary TB with a chest X-ray (CXR) and a symptom questionnaire. Three sputum specimens for bacteriological examination by microscopy and culture were collected from those whose screening was positive. Prevalence was calculated, a multiple logistic regression model was performed to confirm the risk factors, and population attributable fraction (PAF) of each risk factor was calculated to indicate the public health significance. RESULTS: Of 38 888 eligible people from 27 clusters, 34 269 participants finished both questionnaire and physical examination. There were 193 active pulmonary TB cases, 62 of which were bacteriologically confirmed. The estimated prevalence of active pulmonary TB and bacteriologically confirmed TB in those 65 years of age and older was 563.19 per 100 000 (95% CI: 483.73-642.65) and 180.92 per 100 000 (95% CI: 135.89-225.96), respectively. Male sex, older age, living in rural areas, underweight, diabetes, close contact of pulmonary TB (PTB) and previous TB history are all risk factors for TB. The risk of TB increased with increasing age and decreasing body mass index (BMI) after adjusting for other factors, and there is a positive dose-response relationship. CONCLUSIONS: In China, active case finding (ACF) could be implemented among elderly people aged 65 and above with underweight, diabetes, close contact history and previous TB history as a priority, which will get significant yields and be cost-effective.

Comparing yield and relative costs of WHO TB screening algorithms in selected risk groups among people aged 65 years and over in China, 2013.

OBJECTIVE: To calculate the yield and cost per diagnosed tuberculosis (TB) case for three World Health Organization screening algorithms and one using the Chinese National TB program (NTP) TB suspect definitions, using data from a TB prevalence survey of people aged 65 years and over in China, 2013. METHODS: This was an analytic study using data from the above survey. Risk groups were defined and the prevalence of new TB cases in each group calculated. Costs of each screening component were used to give indicative costs per case detected. Yield, number needed to screen (NNS) and cost per case were used to assess the algorithms. FINDINGS: The prevalence survey identified 172 new TB cases in 34,250 participants. Prevalence varied greatly in different groups, from 131/100,000 to 4651/ 100,000. Two groups were chosen to compare the algorithms. The medium-risk group (living in a rural area: men, or previous TB case, or close contact or a BMI <18.5, or tobacco user) had appreciably higher cost per case (USD 221, 298 and 963) in the three algorithms than the high-risk group (all previous TB cases, all close contacts). (USD 72, 108 and 309) but detected two to four times more TB cases in the population. Using a Chest x-ray as the initial screening tool in the medium risk group cost the most (USD 963), and detected 67% of all the new cases. Using the NTP definition of TB suspects made little difference. CONCLUSIONS: To "End TB", many more TB cases have to be identified. Screening only the highest risk groups identified under 14% of the undetected cases,. To "End TB", medium risk groups will need to be screened. Using a CXR for initial screening results in a much higher yield, at what should be an acceptable cost.

Proportions and Risk Factors of Developing Multidrug Resistance Among Patients with Tuberculosis in China: A Population-Based Case-Control Study.

AIMS: Limited studies have been conducted to explore risk factors of developing multidrug-resistant tuberculosis (MDR-TB) in China. This study aimed to find the proportions and risk factors of developing MDR-TB in China among new patients and previously treated tuberculosis (TB) patients. METHODS: A population-based case-control study was conducted from March 2010 to December 2013 in five cities in China. Proportions and risk factors of developing MDR-TB were calculated and analyzed separately for new patients and previously treated patients. RESULTS: The proportion of MDR-TB was 3.9% among new patients and 25.3% among previously treated patients in our study population. The proportion of extensively drug resistant TB was 0.1% among new patients and 1.4% among previously treated patients in our study population. Multivariate analysis found that being registered as migrants (odds ratio [OR] = 6.08; 95% confidence interval [CI]: 1.75-21.09), having more than three affected lung fields (OR = 2.18; 95% CI: 1.20-2.94), having more than 8 months of initial treatment (OR = 2.15; 95% CI: 1.09-4.28), having more than three prior episodes of anti-TB treatment (OR = 3.10; 95% CI: 1.48-6.48), and experiencing failure or continued worsening from the last treatment (OR = 3.82; 95% CI: 1.86-7.85) were associated with developing MDR-TB in previously treated patients with TB. Univariate analysis showed that less than 30 years of living in the same location (p = 0.034) was a risk factor for new patients with MDR-TB. CONCLUSION: The surveillance of multidrug resistance among patients with previously treated TB who also possess these risk factors and the management of patients with MDR-TB should be reinforced.

[A study on the cooperation between centers for disease control and special tuberculosis hospitals for treatment and management of multi-drug resistant tuberculosis].

OBJECTIVE: To improve the effectiveness of case detection and treatment of multi-drug resistant tuberculosis (MDR-TB) by implementing a mechanism of cooperation between hospitals and centers for disease control (CDC). METHODS: Since 1 March 2010, a new mechanism of cooperation between hospitals and CDCs had been established in 5 cities including Daqing, Quzhou, Puyang, Tianjin and Wanzhou in China. Data of MDR-TB case-detection, treatment and economic burdens before the intervention (January 1, 2006-June 30, 2009) and after the intervention (March 1, 2010-February 29, 2012) were collected. Then all data were analyzed by statistical method. RESULTS: After the intervention, samples from 68.4% (5 287/7 733) of smear-positive TB patients in the study regions underwent TB drug-resistant testing, and the number of the detected MDR-TB cases were 9.8 times that prior to the intervention. 93.1% (108/116) of the patients incorporated into the treatment of MDR-TB received the standardized initial chemotherapy program, and the number was 7 times that before the intervention. The referral rates after hospital discharge raised from 0% before the intervention to 92.8% after (90/97) the intervention; and 85.7% (83/97) of the patients received treatment and management by CDC. When the 6-month injection ended, MDR-TB patients still under treatment after the intervention were 84.5% (82/97), and those whose sputum culture became negative were 56.7% (55/97). The proportion of patients with self-paid and with catastrophic expenditures after the intervention were reduced to 18.0% (1 678/9 324) and 44.7% (17/38) respectively, as compared to 75.4% (7 659/10 158) and 76.7% (23/30) respectively before the intervention. CONCLUSION: To establish a well-performed Hospital-CDC cooperation mechanism could promote the performance of MDR-TB case detection and treatment.