Screening for colorectal cancer.
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Colonoscopy↗
Biomedical subjects
Thomas R Frieden
Publications and source records attributed to Thomas R Frieden.
Management of latent tuberculosis infection in immigrants.
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Antitubercular Agents↗
Impact of DOTS compared with DOTS-plus on multidrug resistant tuberculosis and tuberculosis deaths: decision analysis.
OBJECTIVE: This study sought to determine the impact of the World Health Organization's directly observed treatment strategy (DOTS) compared with that of DOTS-plus on tuberculosis deaths, mainly in the developing world. DESIGN: Decision analysis with Monte Carlo simulation of a Markov decision tree. DATA SOURCES: People with smear positive pulmonary tuberculosis. DATA ANALYSIS: Analyses modelled different levels of programme effectiveness of DOTS and DOTS-plus, and high (10%) and intermediate (3%) proportions of primary multidrug resistant tuberculosis, while accounting for exogenous reinfection. MAIN OUTCOME MEASURE: The cumulative number of tuberculosis deaths per 100 000 population over 10 years. RESULTS: The model predicted that under DOTS, 276 people would die from tuberculosis (24 multidrug resistant and 252 not multidrug resistant) over 10 years under optimal implementation in an area with 3% primary multidrug resistant tuberculosis. Optimal implementation of DOTS-plus would result in four (1.5%) fewer deaths. If implementation of DOTS-plus were to result in a decrease of just 5% in the effectiveness of DOTS, 16% more people would die with tuberculosis than under DOTS alone. In an area with 10% primary multidrug resistant tuberculosis, 10% fewer deaths would occur under optimal DOTS-plus than under optimal DOTS, but 16% more deaths would occur if implementation of DOTS-plus were to result in a 5% decrease in the effectiveness of DOTS CONCLUSIONS: Under optimal implementation, fewer tuberculosis deaths would occur under DOTS-plus than under DOTS. If, however, implementation of DOTS-plus were associated with even minimal decreases in the effectiveness of treatment, substantially more patients would die than under DOTS.
Cost-Benefit Analysis↗
Tuberculosis control: past 10 years and future progress.
The number of countries implementing directly observed therapy short-course (DOTS) has grown rapidly in the past decade and more than 10 million patients have now been treated under DOTS. While global case detection rates increased slightly, from 35% to 40% between 1995 and 2000, the proportion attributable to DOTS grew from less than one-third to more than two-thirds. DOTS is replacing inferior treatment but still treating fewer than 40% of estimated new TB cases. Misconceptions threaten to undermine continued success in tuberculosis control. The first misconception is that treatment observation is unnecessary. Treatment observation needs to be made more patient-friendly, but must not be abandoned. The second misconception is that health care reform will strengthen tuberculosis control. TB control is essentially a management problem. Greater accountability of governments, donors and providers is essential. A third misconception is to focus on treating multi-drug-resistant tuberculosis (MDRTB) cases without addressing the root causes of MDRTB. While it is important, on a clinical basis and epidemiologically in some contexts, to care optimally for patients with MDRTB, it is more important to address the cause of MDRTB and to fix the program generating MDRTB. The fourth misconception is an inordinate concern for sustainability. Delaying assistance will make implementation and sustainability in the future more difficult. Tuberculosis control is remarkably inexpensive and cost-effective, but efforts will fail unless programs have the ability to hire staff, purchase supplies, and contract for services efficiently. Critical issues for the future of tuberculosis control are sustained funding, technical rigor, and good management.
Attitude of Health Personnel↗
Processing sputum specimens in a refrigerated centrifuge does not increase the rate of isolation of Mycobacterium tuberculosis.
A total of 1,047 sputum samples from pulmonary tuberculosis patients was collected in cetyl pyridinium chloride-sodium chloride solution. Each sample was divided into two parts and randomly allocated for the isolation of Mycobacterium tuberculosis, with one part to be processed by the standard method and the other by a modified method. In the standard method, the samples were processed by using nonrefrigerated centrifuges, while in the modified method, they were processed by using a refrigerated centrifuge. Fifty-seven samples that yielded contaminants were excluded, and the remaining 990 samples were taken up for analysis. The rates of isolation of M. tuberculosis with the standard and modified methods were 48.6 and 48.1%, respectively, and the difference was not statistically significant (McNemar's test; P > 0.5). However, 51% of the positive cultures were isolated within 2 weeks with the modified method compared to 37% with the standard method (chi-square test; P < 0.001). The results of the study reveal that processing of sputum samples in a refrigerated centrifuge does not improve the rate of isolation but will result in rapid isolation of M. tuberculosis.
Centrifugation↗
Controlling tuberculosis in India.
BACKGROUND: Tuberculosis kills nearly 500,000 people in India each year. Until recently, less than half of patients with tuberculosis received an accurate diagnosis, and less than half of those received effective treatment. METHODS: We analyzed the effects of new policies introduced in 1993 that have resulted in increased resources, improved laboratory-based diagnosis, direct observation of treatment, and the use of standardized antituberculosis regimens and reporting methods. RESULTS: By September 2001, more than 200,000 health workers had been trained, and 436 million people (more than 40 percent of the entire population) had access to services. About 3.4 million patients had been evaluated for tuberculosis, and nearly 800,000 had received treatment, with a success rate greater than 80 percent. More than half of all those treated in the past 8 years were treated in the past 12 months. CONCLUSIONS: India's tuberculosis-control program has been successful in improving access to care, the quality of diagnosis, and the likelihood of successful treatment. We estimate that the improved program has prevented 200,000 deaths, with indirect savings of more than $400 million--more than eight times the cost of implementation. It will be a substantial challenge to sustain and expand the program, given the country's level of economic development, limited primary health care system, and large and mostly unregulated private health care system, as well as the dual threats of the human immunodeficiency virus and multidrug-resistant tuberculosis.
Communicable Disease Control↗
The global tuberculosis situation. Progress and problems in the 20th century, prospects for the 21st century.
Mycobacterium tuberculosis has been identified in prehistoric remains of humans. Despite references to TB by Hippocrates and Galen, humankind had limited understanding of and few tools to defend itself against TB until the later 19th century. Subsequently, landmark advances in the 20th century provided the means to control and prevent this disease. At the same time, epidemiological developments and fundamental problems related to human behavior, socioeconomic conditions, and political circumstances continue to thwart efforts to diminish the burden of suffering and death caused by TB. This article reviewed some of these issues including the global failure of TB control in the late 20th century, the worldwide emergence of drug-resistant TB, the extensive spread of HIV infection and its impact on TB incidence; and changing health care and political environments. The obstacles to TB control remain and will remain challenges in the coming years. Still, recent developments in immunology, biochemistry, and molecular biology suggest that new knowledge and tools are just around the corner. These will enhance the ability to conquer this microbe by the end of the current century.
HIV Infections↗
Can tuberculosis be controlled?
BACKGROUND: Tuberculosis (TB) is nearly 100% curable. However, the ability of medical and public health interventions to control TB, particularly in developing countries, is often doubted. METHODS: We reviewed data for the amenability of TB to control. We considered separately control of deaths, prevalence, rate of infection and incidence. RESULTS: Tuberculosis mortality can be reduced by more than 80% in less than 5 years. The prevalence of TB can be reduced by 30% or more annually; sustained annual decreases of 17% have been documented in a developing country. The TB infection rate can be reduced by 15% annually. In the absence of human immunodeficiency virus (HIV), TB incidence can be decreased by as much as 25% per year and up to 10% annually in developing countries. A high prevalence of untreated HIV infection in the adult population of a developing country will inevitably result in a significant increase in TB incidence despite optimal use of currently available technologies. CONCLUSIONS: Tuberculosis can be controlled if appropriate policies are followed, effective clinical and public health management is ensured, and there are committed and co-ordinated efforts from within and outside the health sector. However, in the context of a large epidemic of AIDS, TB incidence will inevitably increase. By 2001, less than 30% of global TB cases were reported to have received effective diagnosis, treatment and monitoring. Rapid expansion of effective TB control services is urgently required, both to avert the continued high burden of morbidity and mortality from TB and because of the HIV pandemic.
Antitubercular Agents↗
Molecular epidemiology of tuberculosis in a rural area of high prevalence in South India: implications for disease control and prevention.
Molecular and conventional epidemiologic techniques were used to study the mechanisms and risk factors for tuberculosis transmission in a rural area with high prevalence in south India. Restriction fragment length polymorphism analysis with IS6110 and direct repeat probes was performed with 378 Mycobacterium tuberculosis isolates from patients. Forty-one percent of M. tuberculosis isolates harbored a single copy of IS6110. Of 378 patients, 236 had distinct strains; 142 (38%) shared a strain with other patients, indicating recent infection. Older patients, those detected by a house-to-house community survey, and those hospitalized in a sanatorium were more likely to have had a recent infection. These findings suggest that the majority of the tuberculosis cases in south India were due to reactivation; therefore, efforts to control tuberculosis should be sustained.
Adult↗
Evaluation of the phenol ammonium sulfate sedimentation smear microscopy method for diagnosis of pulmonary tuberculosis.
We compared the sensitivity and specificity of the phenol ammonium sulfate (PhAS) sediment smear microscopy method for detection of acid-fast bacilli with those of direct smear microscopy, using culture results for Mycobacterium tuberculosis as the "gold standard." The sensitivities of the PhAS and direct smear methods were 85% (465 of 547) and 83% (454 of 547), respectively, and the specificity of each method was 97%. The PhAS method was better accepted by the laboratory technicians and safer but necessitates an overnight sedimentation, which delays reporting of results until 1 day after sputum collection.
Ammonium Sulfate↗
Inefficiency of 0.3% carbol fuchsin in ziehl-neelsen staining for detecting acid-fast bacilli.
We compared the sensitivity and specificity of a modified Ziehl-Neelsen (modified-ZN) staining method for acid-fast bacilli (AFB) with that of the standard Ziehl-Neelsen (standard-ZN) staining method, using culture results with Mycobacterium tuberculosis as the "gold standard." The sensitivity (72%; 101 of 140) of the modified-ZN staining method, which uses 0.3% carbol fuchsin, was significantly lower than that of the standard-ZN staining method (84%; 117 of 140); the modified-ZN method missed 21% of cases detected by the standard-ZN method and 11% more of culture-positive samples than the standard-ZN method. The World Health Organization recommendation of 0.3% carbol fuchsin in the ZN method for staining AFB needs to be reconsidered.
Coloring Agents↗
Rapid DOTS expansion in India.
Since late 1998 the coverage of the DOTS strategy in India has been expanded rapidly. In both 2000 and 2001 the country probably accounted for more than half the global increase in the number of patients treated under DOTS and by early 2002 more than a million patients were being treated in this way in India. As a result, nearly 200 000 lives were saved. The lessons learnt relate to the importance of the following elements of the programme: (1) getting the science right and ensuring technical excellence; (2) building commitment and ensuring the provision of funds and flexibility in their utilization; (3) maintaining focus and priorities; (4) systematically appraising each area before starting service delivery; (5) ensuring an uninterrupted drug supply; (6) strengthening the established infrastructure and providing support for staff; (7) supporting the infrastructure required in urban areas; (8) ensuring full-time independent technical support and supervision, particularly during the initial phases of implementation; (9) monitoring intensively and giving timely feedback; and (10) continuous supervision. Tuberculosis (TB) control still faces major challenges in India. To reach its potential, the control programme needs to: continue to expand so as to cover the remaining half of the country, much of which has a weaker health infrastructure than the areas already covered; increase its reach in the areas already covered so that a greater proportion of patients is treated; ensure sustainability; improve the patient-friendliness of services; confront TB associated with human immunodeficiency virus (HIV) infection. It is expected that HIV will increase the number of TB cases by at least 10% and by a considerably higher percentage if HIV becomes much more widespread. India's experience shows that DOTS can achieve high case-detection and cure rates even with imperfect technology and often with an inadequate public health infrastructure. However, this can only happen if the delivery programme is appropriately designed and effectively managed.
Antitubercular Agents↗
Controlling multidrug-resistant tuberculosis and access to expensive drugs: a rational framework.
The emergence and spread of multidrug-resistant tuberculosis (MDR-TB), i.e. involving resistance to at least isoniazid and rifampicin, could threaten the control of TB globally. Controversy has emerged about the best way of confronting MDR-TB in settings with very limited resources. In 1999, the World Health Organization (WHO) created a working group on DOTS-Plus, an initiative exploring the programmatic feasibility and cost-effectiveness of treating MDR-TB in low-income and middle-income countries, in order to consider the management of MDR-TB under programme conditions. The challenges of implementation have proved more daunting than those of access to second-line drugs, the prices of which are dropping. Using data from the WHO/International Union Against Tuberculosis and Lung Disease surveillance project, we have grouped countries according to the proportion of TB patients completing treatment successfully and the level of MDR-TB among previously untreated patients. The resulting matrix provides a reasonable framework for deciding whether to use second-line drugs in a national programme. Countries in which the treatment success rate, i.e. the proportion of new patients who complete the scheduled treatment, irrespective of whether bacteriological cure is documented, is below 70% should give the highest priority to introducing or improving DOTS, the five-point TB control strategy recommended by WHO and the International Union Against Tuberculosis and Lung Disease. A poorly functioning programme can create MDR-TB much faster than it can be treated, even if unlimited resources are available. There is no single prescription for controlling MDR-TB but the various tools available should be applied wisely. Firstly, good DOTS and infection control; then appropriate use of second-line drug treatment. The interval between the two depends on the local context and resources. As funds are allocated to treat MDR-TB, human and financial resources should be increased to expand DOTS worldwide.
Antitubercular Agents↗