In addition to summarizing the available evidence, the reviews undertaken for these consolidated guidelines revealed several gaps in current knowledge about critical areas in DR-TB treatment and care. The estimates of effect for patient studies were commonly assigned a low or very low certainty rating, which explains why most of the recommendations in these guidelines are conditional. Some gaps persist from those identified in previous TB treatment guidelines (11, 12). When completing the GRADE evidence-to-decision tables, there was a lack of studies on how patients, caregivers and other stakeholders value different treatment options and outcomes (e.g. time to sputum conversion, cure, treatment failure and relapse, death and serious adverse events). Areas that would be relevant to many priority questions in the programmatic management of DR-TB include implementation research; studies of resource use; incremental cost, acceptability, feasibility and equity; values and preferences of patients and health care workers; and the inclusion of indicators of quality of life.
The research gaps that were identified by the successive GDGs are grouped by the respective sections of these guidelines, although some are interlinked.