Subgroup considerations Decentralized care may not be appropriate for patients with severe TB disease, extremely infectious forms of the disease, serious comorbidities or patients for whom treatment adherence is a concern. Measures to protect the safety of patients on MDR-TB regimens – especially those containing new or novel medicines – need to be maintained in outpatient settings. These recommendations for decentralized care should not preclude hospitalization if appropriate. This review did not include patients requiring surgical care. Implementation considerations Ambulatory care: The cost varied widely across the modelled settings. The cost per disabilityadjusted life year (DALY) averted by an ambulatory model in one setting was sometimes higher than the cost per DALY averted by a hospitalization model in another setting. However, cost per DALY averted was lower under outpatient-based care than under inpatient-based care in the vast majority (at least 90%) of settings for which cost–effectiveness was modelled. The variation in cost–effectiveness among settings correlated most strongly with the variation in the cost of general health-care services and other non-drug costs. Despite the limitations in the data available, there was no evidence that conflicted with the recommendation or which indicated that treatment in a hospital-based model of care leads to a more favourable treatment outcome. The overall cost–effectiveness of care for a patient receiving treatment for MDR-TB can be improved with an ambulatory model. The benefits include reduced use of resources, and at least as many deaths avoided among primary and secondary cases as with hospitalization models. This result is based on clinic-based ambulatory treatment (i.e. patients attended a health-care facility); in some settings, home-based ambulatory treatment (provided by a health worker in the community) might improve cost– effectiveness even further. The benefit of reduced transmission can be expected only if proper infection control measures are in place in both the home and the clinic. Potential exposure to people who are infectious can be minimized by reducing or avoiding hospitalization where possible, reducing the number of outpatient visits, avoiding overcrowding in wards and waiting areas, and prioritizing community-care approaches for TB management (134). The regimen used in one of the studies on ambulatory care derived from a period when the combinations of medicines were not yet optimized, so the outcomes achieved were probably inferior to those that can be obtained with the regimens in use today. Admission to hospital for patients who do not warrant it may also have important social and psychological consequences that need to be taken into account. There may be some important barriers to accessing clinic-based ambulatory care, including distance of travel and other costs to individual patients. Shifting costs from the service provider to the patient must be avoided, and implementation may need to be accompanied by appropriate enablers. While placing patients on adequate therapy would be expected to decrease the bacterial load and transmission of DR-TB, infection control measures for home-based and clinic-based measures will need to be part of an ambulatory model of care in order to decrease the risk of transmission in households, the community and clinics. TB control programmes will have to consider whether they are capable of reallocating resources from hospital care to ambulatory care support in order to undertake the necessary changes in patient management. The choice between these options will affect the feasibility of implementing the recommendation in a particular programme. A high value was placed on conserving resources and on patient outcomes such as preventing death and transmission of MDR-TB as a result of delayed diagnosis and inpatient treatment. There should always be provision for a back-up facility to manage patients who need inpatient treatment. This may be necessary in certain groups of patients at particular risk, such as children during the intensive phase, among whom close monitoring may be required for a certain period of time. Decentralized care: National TB programmes should have standardized guidelines regarding which patients are eligible for decentralized care. Patient preference should be given a high value when choosing between centralized or decentralized care. Decentralized care for MDR-TB patients requires appropriate treatment supervision, patient education and social support, staff training, infection control practices and quality assurance. The optimal treatment supervision options and treatment adherence interventions recommended in section 2.1 should be considered for MDR-TB patients on decentralized care. Several of the studies in the review addressed treatment costs. However, cost estimates were found to vary widely and no concrete recommendations could be made on that basis. Resource requirements are likely to vary because TB treatment programmes are highly variable and costs vary across different countries. The GDG raised several issues for TB programmes to consider. Although hospitalization is generally thought to be more expensive than outpatient care, the costs of good outpatient programmes can also be significant. Additionally, outpatient costs may vary significantly according to the services provided. One cost-saving measure to consider in decentralized care is that patients may be able to receive treatment faster. The financial benefits of decentralized care would include finding patients before they become very ill and require more medical care, while treating people before TB can be transmitted to contacts would be a public health benefit. If a patient is living with a person from a high-risk group (i.e. HIV-positive or a young child), there may be complications in sending the patient home for treatment. However, the risk posed to highrisk groups varies significantly, depending on whether the TB programme gives preventive treatment to high-risk persons. Studies involving preventive therapy for MDR-TB are ongoing. An additional implementation concern is that in some places it may be illegal to treat MDR-TB patients in a decentralized setting, especially when the treatment involves injections. Such legal concerns need to be addressed.