Using computerized clinical decision support for latent tuberculosis infection screening

BACKGROUND: The Centers for Disease Control and Prevention (CDC) has published guidelines recommending screening high-risk groups for latent tuberculosis infection (LTBI). The goal of this study was to determine the impact of computerized clinical decision support and guided web-based documentation on screening rates for LTBI. DESIGN: Nonrandomized, prospective, intervention study. SETTING AND PARTICIPANTS: Participants were 8463 patients seen at two primary care, outpatient, public community health center clinics in late 2002 and early 2003. INTERVENTION: The CDC's LTBI guidelines were encoded into a computerized clinical decision support system that provided an alert recommending further assessment of LTBI risk if certain guideline criteria were met (birth in a high-risk TB country and aged <40). A guided web-based documentation tool was provided to facilitate appropriate adherence to the LTBI screening guideline and to promote accurate documentation and evaluation. Baseline data were collected for 15 weeks and study-phase data were collected for 12 weeks. MAIN OUTCOME MEASURES: Appropriate LTBI screening according to CDC guidelines based on chart review. RESULTS: Among 4135 patients registering during the post-intervention phase, 73% had at least one CDC-defined risk factor, and 610 met the alert criteria (birth in a high-risk TB country and aged <40 years) for potential screening for LTBI. Adherence with the LTBI screening guideline improved significantly from 8.9% at baseline to 25.2% during the study phase (183% increase, p < 0.001). CONCLUSIONS: This study demonstrated that computerized, clinical decision support using alerts and guided web-based documentation increased screening of high-risk patients for LTBI. This type of technology could lead to an improvement in LTBI screening in the United States and also holds promise for improved care for other preventive and chronic conditions.     

Early therapy for latent tuberculosis infection

The risk of developing active tuberculosis is highest within the first 2 years of infection. Therefore, an intervention that targets persons with recent infection, such as identifying contacts of active cases, could be particularly effective as an epidemic control measure. A mathematical model of a tuberculosis epidemic is formulated and used to evaluate the strategy of targeting therapy to persons with recently acquired latent tuberculosis infection. The model is used to quantify the effectiveness of therapy for early latent tuberculosis infection in reducing the prevalence of active tuberculosis. The model is also used to demonstrate how effective therapy for early latent tuberculosis infection has to be to eliminate tuberculosis, when used in conjunction with therapy for active tuberculosis. Analysis of the model suggests that programs such as contact investigations, which identify and treat persons recently infected with Mycobacterium tuberculosis, may have a substantial effect on controlling tuberculosis epidemics.     

The need for performance measures on testing for latent tuberculosis infection in primary care

BACKGROUND: The millions of people living in the United States with latent tuberculosis infection (LTBI) represent a reservoir of potentially active tuberculosis (TB) disease. When LTBI is left to activate, the consequences may include intense suffering, permanent disability, and high economic costs for patients, their caretakers, and society at large as TB spreads. The introduction of performance measures would improve accountability for quality of care and to reduce disparities, especially if the measures are group-targeted. PERFORMANCE MEASURES PROPOSAL: One National Quality Forum-endorsed measure (#0408) calculates the rate of TB screening in persons with HIV. Using the measure as a model, a set of performance measures is proposed. Denominators will include all persons in a given high-risk category, and numerators will include those persons from the denominators with LTBI test results. National guidelines informed appropriate exclusions. IMPLEMENTATION CHALLENGES AND SOLUTIONS: Challenges to implementation include lack of TB knowledge among primary care providers, potential for overwhelming already burdened schedules, and stigma associated with TB. However, the new measures, along with publication of educational resources, would raise clinicians' awareness. Short checklists and electronic supports would minimize time pressures. The routinization of screening would help reduce stigma. Finally, new federal funding and political will for electronic health records would facilitate data collection and impact assessment. CONCLUSIONS: TB sits at the crossroads of health and economic inequity and is a huge public health problem. The proposed performance measures will address a neglected secondary prevention opportunity and will be consistent with national priorities and health reform.     

Immigrant screening for latent tuberculosis in Norway: a cost-effectiveness analysis

The incidence of tuberculosis (TB) disease has increased in Norway since the mid-1990s. Immigrants are screened, and some are treated, for latent TB infection (LTBI) to prevent TB disease (reactivation). In this study, we estimated the costs of both treating and screening for LTBI and TB disease, which has not been done previously in Norway. We developed a model to indicate the cost-effectiveness of four different screening algorithms for LTBI using avoided TB disease cases as the health outcome. Further, we calculated the expected value of perfect information (EVPI), and indicated areas of LTBI screening that could be changed to improve cost-effectiveness. The costs of treating LTBI and TB disease were estimated to be €1938 and €15,489 per case, respectively. The model evaluates four algorithms, and suggests three cost-effective algorithms depending on the cost-effectiveness threshold. Screening all immigrants with interferon-gamma release assays (IGRA) requires the highest threshold (€28,400), followed by the algorithms “IGRA on immigrants with risk factors” and “no LTBI screening.” EVPI is approximately €5 per screened immigrant. The costs for a cohort of 20,000 immigrants followed through 10 years range from €12.2 million for the algorithm “screening and treatment for TB disease but no LTBI screening,” to €14 million for “screening all immigrants for both TB disease and LTBI with IGRA.” The results suggest that the cost of TB disease screening and treatment is the largest contributor to total costs, while LTBI screening and treatment costs are relatively small. Increasing the proportion of IGRA-positive immigrants who are treated decreases the costs per avoided case substantially.     

Predictors of adherence to treatment for latent tuberculosis infection in high-risk Latino adolescents: a behavioral epidemiological analysis

The objective was to test whether theoretical variables predict adherence to treatment for latent tuberculosis infection in high-risk Latino adolescents. 286 Latino adolescents, age 13-18 years, were recruited from 10 middle/high schools in San Diego County, San Diego, USA. Participants completed a baseline interview and up to 9 monthly interviews. The cumulative number of pills consumed in 9 months was regressed on 16 independent variables, entered hierarchically in seven blocks. The final model accounted for 25% of the variance in adherence to isoniazid (INH), F (16, 230)=4.69, p<0.001. Adherence counseling (+), age (-), grades (+), being bicultural (+), and risk behaviors (-) were significantly related to adherence. Learning theories presume that adherence to medical regimens requires social support and freedom from physical and social barriers. Results support these theories. Future studies should explore additional precepts in order to identify additional predictors and to maximize adherence to INH among Latino adolescents and other high-risk populations. Doing so should decrease the risk of active TB among high-risk racial/ethnic and foreign-born populations.     

Increasing Latino adolescents' adherence to treatment for latent tuberculosis infection: a controlled trial

OBJECTIVES: We sought to determine the efficacy of coaching Latino adolescents with latent tuberculosis infection to adhere to isoniazid treatment. METHODS: Participants (n = 286) were randomly assigned to adherence coaching, attention control, or usual care groups. Adherence was measured via interviews and validated with urine assays. RESULTS: Coaching resulted in significant increases in adherence compared with attention and usual care groups. Bicultural adolescents were more likely to be adherent than those most or least acculturated. Age and risk behavior were negatively related to adherence. CONCLUSIONS: Coaching can increase Latino adolescents' adherence to treatment for latent tuberculosis infection and should contribute to tuberculosis control for adolescents at high risk of contracting the disease.     

Completion of screening for latent tuberculosis infection among immigrants

The objective of our study was to evaluate the sociodemographic factors associated with completion of screening for latent tuberculosis infection (LTBI) among undocumented immigrants in Brescia, Italy. Screening for LTBI was offered to 649 immigrants; 213 (33%) immigrants completed the first step of screening; only 44% (55/124) of individuals with a positive tuberculin skin test result started treatment for LTBI. The univariate analysis showed that being unmarried, of Senegalese nationality and being interviewed by a health-care worker with the same native language as the immigrant were significantly associated with completion of screening for LTBI. In the multiple logistic regression, being interviewed in the native language of the health-care worker (OR 2.5, 95% CI 1.3-4.8, P = 0.004) and being of Senegalese origin (OR 2.3, 95% CI 1.4-3.6, P = 0.0005) were independently associated with adherence to LTBI screening. Our results suggest that knowledge of the sociodemographic characteristics of immigrants, and the participation of health-care workers of the same cultural origin as the immigrant during the visits, can be an important tool to improve completion of screening for LTBI.     

潜伏性结核分枝杆菌感染动物模型

全球1/3的人口感染结核分枝杆菌(Mycobacterium tuberculosis,MTB),其中大部分为潜伏感染［1］。研究人员对MTB潜伏感染的关注度日益增高。笔者针对当前研究MTB潜伏感染所使用的各种动物模型进行综述,分析包括小鼠、豚鼠、兔以及非人灵长类的动物模型优势和局限性,以期为研究人员正确选择合适的MTB潜伏感染动物模型以及深入开展潜伏感染的研究提供帮助。     

Cost-effectiveness of novel vaccines for tuberculosis control: a decision analysis study

Background  

The development of a successful new tuberculosis (TB) vaccine would circumvent many limitations of current diagnostic and treatment practices. However, vaccine development is complex and costly. We aimed to assess the potential cost effectiveness of novel vaccines for TB control in a sub-Saharan African country - Zambia - relative to the existing strategy of directly observed treatment, short course (DOTS) and current level of bacille Calmette-Guérin (BCG) vaccination coverage.     

Screening Latino adolescents for latent tuberculosis infection (LTBI)

OBJECTIVES: To investigate the rates of latent TB infection (LTBI) in a sample of young people in San Diego County and examine potential predictors of a positive tuberculin skin test (TST). METHODS: Latino and foreign-born students from ten public middle and high schools were invited to screenings along with a random 10% sample of all other students. After obtaining parental consent, Mantoux tests were placed (N=2,698) and read (n=2,667 [98.9%]) in 48-72 hours. A positive TST was defined as > or =10 mm induration. The mean age of the sample was 14.34 years (SD=1.81); 50.1% were female (n=1,353); 78.5% were Latino (n=2,108); 35.7% were foreign-born (n=939); and 44.3% were uninsured (n=930). RESULTS: The positive TST rate for Latinos was 21.8% vs. 5.6% for non-Latinos, p<0.001. Foreign-born Latinos had the highest infection rate (31.3%), followed by foreign-born non-Latinos (20.4%), U.S.-born Latinos (15.4%), and U.S.-born non-Latinos (1.0%), p<0.001. Logistic regression was conducted to determine predictors of TST positivity. Being Latino (odds ratio [OR]=3.27), uninsured (OR=1.60), foreign-born (OR=3.90), and living in the south county region closest to the U.S./Mexico border (OR=2.72) were significant predictors. CONCLUSIONS: Results suggest that Latino youth near the California/Mexico border are at high risk for infection, for remaining undiagnosed, and for being under-treated for LTBI.     

Ethical evaluation of immigration screening policy for latent tuberculosis infection

Objective : In Australia and New Zealand, immigration screening policy relating to tuberculosis is targeted towards identifying potential new arrivals with active infectious pulmonary disease. Recently, extensions of immigration policies to include latent tuberculosis infections have been proposed, which raise a new spectrum of ethical issues. Methods : Existing Australian and New Zealand immigration policy was reviewed. A principle‐based analytic framework was adopted for consideration of the ethical implications of proposed public health policy. Potential extensions of current policy in relation to latent tuberculosis infection are evaluated using this approach. Results : Current immigration policies related to tuberculosis focus on identification of immigrants with active infection. A principle‐based analytic framework allows evaluation of potential extensions of public health policy to incorporate screening and treatment for latent tuberculosis. Conclusions : Our paper explores the dynamic ethical tensions related to burdens and benefits of immigration screening for latent tuberculosis, and suggests that such policies could be justified under certain circumstances, including non‐arbitrary screening and post‐arrival management. The results of testing should not influence immigration outcome, but be used to mandate medical review and consideration of voluntary preventative treatment. Implications : Immigration strategies targeting latent tuberculosis could be ethically justified within appropriate guidelines. Proposed changes to policy should be evaluated on ethical grounds prior to introduction.     

Tuberculin testing to detect latent tuberculosis in developing countries

Despite the multiple studies done over several decades that have established the utility of the tuberculin skin test (TST) for the diagnosis of latent tuberculosis, the test is rarely used in developing countries experiencing a resurgence of tuberculosis. Nevertheless, several clinical trials have found that treatment of HIV-positive or HIV-negative persons with latent tuberculosis is effective in the prevention of the clinical activation of tuberculosis. Clinicians commonly justify their failure to diagnose and treat latent tuberculosis with the belief that BCG vaccine, even when it is used in infancy, will cause false positive reactivity in the TST. The important study by Gustafson and colleagues from Guinea-Bissau in this issue of the journal refutes this belief. In this study only persons with a history of BCG who also had household contact with an active case of tuberculosis had increased rates of TST positivity. Although the current emphasis is on directly observed therapy, short course (DOTS) to control tuberculosis is necessary and critically important, it is not always sufficient to control the tuberculosis epidemic in some countries with major epidemics of HIV. In many of these countries, early diagnosis of active tuberculosis and prevention of activation of latent tuberculosis will also be needed. The evidence from the Guinea-Bissau study suggests that a history of BCG vaccination should not be an obstacle to the diagnosis and treatment of latent tuberculosis.     

Prevalence of latent tuberculosis infection in German radiologists

Healthcare workers have an increased risk of tuberculosis infection compared with the general population. There have been few attempts to quantify the prevalence of latent tuberculosis infection amongst German healthcare workers, due to inadequacy of the current tuberculin skin test (TST). Therefore, it was our aim to investigate the prevalence of latent tuberculosis in this cohort using a tuberculosis-specific ELISpot (T-SPOT.TB) test and to compare the performance of this test to that of the TST. Ninety-five healthy participants working in departments of radiology were examined by ELISpot, lymphocyte transformation test and TST. For cellular in-vitro tests, tuberculosis-specific peptides and purified protein derivate (PPD) were used as antigens. These tests were combined with a questionnaire on prior tuberculosis exposure. Out of 95 healthcare workers, only one (1%) was defined as positive by T-SPOT.TB, 92 (97%) by PPD-ELISpot, 78 (82%) by PPD-lymphocyte transformation test and 32 (34%) by TST. Multivariate analysis showed that the TST was significantly affected (P<0.0001 and P=0.001, respectively) by foreign birth and prior skin testing. The T-SPOT.TB test results were independent of foreign birth, prior skin testing and prior vaccination against tuberculosis. In contrast to the TST, T-SPOT.TB appears to be an accurate and useful tool to track tuberculosis infection in this at-risk group. With only one of 95 participants having acquired latent tuberculosis, these preliminary results argue for a low incidence of latent tuberculosis in German radiologists.     

结核定点医院医护人员结核潜伏感染对比研究

目的对比结核病定点医院呼吸科及结核科医护人员结核分枝杆菌潜伏感染情况,评估两科医护人员感染风险差异,为结核病定点医院调整防控措施提供科学依据。方法选取2018年1月-2018年5月某沿海城市结核病定点医院的呼吸科及结核病科工作人员101名,同时使用结核分枝杆菌感染T细胞斑点试验(mycobacterium tuberculosis infection T cell spot test, T-SPOT.TB)及结核菌素皮肤试验(tuberculin skin test,TST)对两科医护人员进行结核菌潜伏感染率调查;同期收集院感科关于医护人员及患者口罩佩戴情况的相关资料、随访调查患者咳嗽礼仪知晓情况,进行整合分析。结果呼吸科医护人员T-SPOT.TB阳性率为26.79%,结核科为22.22%,无统计学差异(χ~2=0.279,P=0.597),呼吸科医护人员TST阳性率为48.21%,高于结核科24.44%(χ~2=6.007,P=0.014);进一步比较分析发现,呼吸科医生的TST阳性率为52.63%,高于结核科医生的9.09%(P=0.023);结核科的医务人员及患者的口罩佩戴率和佩戴正确率均高于呼吸科(P<0.05);结核科患者的咳嗽礼仪知晓率为82.82%,高于呼吸科患者26.70%(χ~2=247.76,P<0.05);随着TST试验阳性标准的提高,TST、T-SPOT.TB试验的一致性水平越来越高(平均直径≥5 mm Kappa=0.331、平均直径≥10 mm Kappa=0.661平均直径≥15 mm Kappa=0.888)。结论上调TST试验的阳性判断标准可以提高TST和T-SPOT.TB试验的一致性,以有效发现结核病潜伏感染者;应提高结核病定点医院呼吸科医护人员结核菌感染的自我保护意识,对医务人员、患者进行正确佩戴口罩及咳嗽礼仪的指导,以提升结核病定点医院整体的院内防控水平。     

Amniocentesis or chorionic villus sampling for prenatal genetic testing: a decision analysis

We used decision analysis to examine the strategies of amniocentesis, chorionic villus sampling, and no prenatal testing for a pregnant woman who would be 35 years of age at the expected date of delivery. Probabilities were obtained from the obstetric and genetic literature, and utilities from previously published standard reference gambles and from responses of obstetric residents and students recorded on a linear rating scale. The expected utility of amniocentesis exceeded that of chorionic villus sampling by 0.1 utility units, and of no prenatal testing by 0.12 utility units. The decision was insensitive to clinically plausible values for the probabilities of spontaneous abortion after amniocentesis and chorionic villus sampling, the probabilities of abnormal and indeterminate chorionic villus sampling results, the probability of an abnormal amniocentesis result after an indeterminate chorionic villus sampling, the sensitivities and specificities of amniocentesis and chorionic villus sampling, and the probabilities of significant maternal morbidity after first- and second-trimester therapeutic abortion. Chorionic villus sampling was preferred to amniocentesis when the utility of a first-trimester therapeutic abortion exceeded that of a second-trimester abortion by 23.2 utility units, or when the anxiety "cost" of awaiting second-trimester amniocentesis results exceeded 0.1 utility unit. We conclude that over a range of assumptions concerning the probabilities involved in the prenatal testing decision, amniocentesis was preferred to chorionic villus sampling. However, for a decision maker for whom a second-trimester therapeutic abortion would be significantly less acceptable than a first-trimester procedure, or for whom the anxiety of awaiting second-trimester chromosomal diagnosis might be an important consideration, chorionic villus sampling could become the procedure of choice.     

Early life patterns of common infection: a latent class analysis

Early life infection has been implicated in the aetiology of many chronic diseases, most often through proxy measures. Data on ten infectious symptoms were collected by parental questionnaire when children were 6 months old as part of the Avon Longitudinal Study of Parents and Children, United Kingdom. A latent class analysis was used to identify patterns of infection and their relationship to five factors commonly used as proxies: sex, other children in the home, maternal smoking, breastfeeding and maternal education. A total of 10,032 singleton children were included in the analysis. Five classes were identified with differing infectious disease patterns and children were assigned to the class for which they had a highest probability of membership based on their infectious symptom profile: ‘general infection’ (n = 1,252, 12.5%), ‘gastrointestinal’ (n = 1,902, 19.0%), ‘mild respiratory’ (n = 3,560, 35.5%), ‘colds/ear ache’ (n = 462, 4.6%) and ‘healthy’ (n = 2,856, 28.5%). Females had a reduced risk of being in all infectious classes, other children in the home were associated with an increased risk of being in the ‘general infection’, ‘mild respiratory’ or ‘colds/ear ache’ class. Breastfeeding reduced the risk of being in the ‘general infection’ and ‘gastrointestinal’ classes whereas maternal smoking increased the risk of membership. Higher maternal education was associated with an increased risk of being in the ‘mild respiratory’ group. Other children in the home had the greatest association with infectious class membership. Latent class analysis provided a flexible method of investigating the relationship between multiple symptoms and demographic and lifestyle factors.     

Factors associated with latent tuberculosis infection in the contacts of tuberculosis patients

BACKGROUND: As tuberculosis control programs have reached acceptable levels in the identification and treatment of persons with active tuberculosis, the next step should be to develop methods of preventing new cases. Persons with latent tuberculosis infection (LTI) are considered to have a higher risk of developing active tuberculosis. The objective of this study was to evaluate the prevalence of LTI and its associated factors in the contacts of tuberculosis patients. METHODS: We studied the contacts of tuberculosis patients who were examined in the Center for Tuberculosis Control and Prevention in Lleida (Spain) from 1991-1997. Factors associated with the index case (demographic, radiographic, bacteriologic and therapeutic) and tuberculin skin test results and demographic data in contacts were collected. Data on HIV infection, injection drug use and alcohol consumption in tuberculosis patients were also collected. The associations were assessed by obtaining crude and adjusted odds ratios. RESULTS: The prevalence of LTI among contacts was 36.1% (780/2,161). In the multivariate analysis a higher frequency of LTI was detected in contacts older than 14 years (ORa = 3.34; 95% CI, 2.51-4.45), contacts who had a higher degree of exposure to the index case (ORa = 1.96; 95% CI, 1.59-2.42), contacts of pulmonary tuberculosis patients (ORa = 1.54; 95% CI, 1.01-2.35), contacts of patients with a positive sputum smear (ORa = 1.51; 95% CI, 1.15-1.99), contacts of patients with caverns on chest x-ray (ORa = 1.27; 95% CI, 1.01-1.61) and contacts of patients with delayed treatment (ORa = 1.31; 95% CI, 1.05-1.62). CONCLUSIONS: The overall prevalence of LTI in the contacts of patients with tuberculosis was high. Among the factors studied, delayed treatment in the index case was independently associated with the frequency of LTI in tuberculosis contacts. Measures for the early diagnosis and treatment of tuberculosis should be intensified.