Chapter 4 - The DOTS Strategy Today
The DOTS strategy takes sound technology--the successful components of TB control--and packages it with good management practices for widespread use through the existing primary health care network.
It has proven to be a successful, innovative approach to TB control in countries such as China, Bangladesh, Viet Nam, Peru, and countries of West Africa. However, new challenges to the implementation of DOTS include health sector reforms, the worsening HIV epidemic, and the emergence of drug-resistant strains of TB.
The technical, logistical, operational and political aspects of DOTS work together to ensure its success and applicability in a wide variety of contexts.
Table 1. Technical, Logisticai, Operational and Political Aspects of DOTS
TECHNICAL
･ Case detection and diagnosis
･ Standardized short-course drugs
･ Direct observation at least during the initial phase
･ Recording and reporting of progress and cure
LOGISTICAL
･ Dependable drug supply to the patient level
･ Laboratories for microscopy
･ Supervision and training of health care workers
OPERATI0NAL
･ Flexibility in implementation of technical aspects
POLITICAL
･ Sustainability
･ Capacity strengthening
Technical Aspects
Case Detection and Diagnosis
Case detection is the use of sputum smear microscopy to identify people with pulmonary TB among those attending general health services. Sputum smear microscopy is the most cost-effective method of screening pulmonary TB suspects. Although the ratio of different types of TB vary according to local situations, the percentage of sputum smear-positive pulmonary cases detected by microscopy is usually in the range of 50-60 percent; 35-40 percent are sputum smear-negative pulmonary cases; and 10-15 percent extra-pulmonary cases.
TB is diagnosed using patient history, clinical examination and diagnostic tests. When a sputum sample is submitted to the laboratory (usually at a district level health facility), the results of the microscopic examination are entered into the laboratory register. All TB suspects must have a sputum smear microscopy exam and all patients diagnosed with TB must be registered, treated and cured.
In areas of high HIV prevalence, it is often difficult to clinically distinguish pulmonary TB from other HIV-related pulmonary diseases. There has also been an increase in reported case rates of smear-negative pulmonary TB in association with the TB/HIV co-epidemic. The extent of over-diagnosis of smear-negative pulmonary TB in those settings is not known. It is therefore important to follow recommended diagnostic guidelines as closely as possible in order to diagnose smear-negative pulmonary TB accurately.
Standardized Short-course Treatment, with Direct Observation in the Initiai Phase
Short-course drug treatment refers to a treatment regimen of a combination of powerful anti-TB drugs lasting six to eight months. This compares with a long-course regimen, which lasts 12-18months. Standardized regimens follows national policy and international recommendations for effective TB treatment based on whether the patient is classified as a new case, a relapse, a treatment failure, treatment after an interruption, or a chronic case. The most common anti-TB drugs used are isoniazid, rifampicin, pyrazinamide, streptomycin ethambutol and thioacetazone.
Generally, treatment is the same for HIV-infected as for non-HIV-infected patients, with the exception of thioacetazone. This drug is associated with a high risk of severe, and sometimes fatal, skin reactions in HIV-infected individuals. Ethambutol should be substituted for thioacetazone in patients with known or suspected HIV infection. It is recognized that some countries do not have the resources to substitute ethambutol for thioacetazone. Wherc it is not possible to avoid the use of this drug, it is imperative to counsel patients on its potential risks and to advise them to stop thioacetazone at once and report to a health unit if itching or a skin reaction occurs.
Direct obsavation of patients taking their medications is essential during the intensive phase of treatment (the first two months) to ensure that the drugs are taken in the right combinations and for the appropriate duration.
With direct observation of treatiment the patient doesn't bear the sole responsibility of adhering to treatment. Health care workers, public health officials, governments, and communities must all share the responsibility and provide the support patients need to continue and finish treatment. One of the aims of effective TB control is to organize TB services so that the patient has flexibility in where he or she receives treatment, for example in the home or at the workplace. Treatment observers can be anyone who is willing, trained, responsible, acceptable to the patient and accountable to the TB control services.
Recording and Reporting
The recording and reporting system for evaluation of patient progress and treatment outcome provides core information for effective management of both TB patients and health care services. The system consists of: a laboratory register that contains a log of all patients who have had a smear test done; patient treatment cards that detail the regular intake of medication and follow-up sputum examinations; and the TB register, which lists patients commencing treatment and monitors their individual and collective progress towards cure.
The laboratory technician records patient details in the laboratory register. A patient's details are entered with a serial identification number. The results of the sputum examination are then recorded in the general health facility where the patient is registered for treatment. At the end of two months (the intensive phase of treatment), between 75-85 percent of all new smear-positive cases normally become sputum smear-negative, and no longer infectious. This result is also recorded in the laboratory register. Monitoring smear-conversion from positive to negative smear after the initial two to three months of treatment is the most appropriate way to assess that the patient has taken the prescribed medications.
Each person diagnosed with TB (smear-positive, smear-negative, or extrapulmonary) has a patient treatment card. This card also records basic epidemiological and clinical information, and the administration of drugs. The health worker uses the patient treatment card for recording treatment and for follow-up. During the continuation phase and at the end of treatment of sputum smear-positive cases, patients are required to submit sputum samples for microscopy to ensure that they become and remain negative--and therefore cured of TB.
