Consolidated Guidelines

The process of peer review involved an External Review Group which was composed of experts and end-users from national programmes, technical agencies and WHO regional offices. These persons provided their reviews and inputs on the completed draft guidelines after all comments by GDG members were incorporated.

The development of these guidelines required a substantial evidence review and assessment using the GRADE process, as stipulated by WHO's Guidelines Review Committee [7]. The systematic reviews focused primarily on the randomized controlled trials with direct comparison between the intervention and comparator. However, data on the outcomes from the observational cohort studies were also summarized and assessed by the GDGs, especially when limited or no evidence from randomized controlled trials was available.

The recommendations in these guidelines qualify both their strength and in the certainty of the evidence on which they are based. The certainty of the evidence is categorized into four levels (Table 1). The criteria used by the evidence reviewers to qualify the certainty of evidence are summarized in the GRADE tables (see Web Annex 4). Several factors may increase or decrease the certainty of evidence (see tables 12.2b and 12.2c in the WHO handbook for guideline development [6].

The scope of the 2021 update of the DS-TB treatment guideline was to consolidate in one document all the previous evidence-based policy recommendations on treatment of DS-TB (previously presented in two separate guideline documents) and to add new recommendations. Thus the current module brings together all recommendations that are valid from previous guidelines without any modifications as no additional reviews have been performed.

The present guideline update aims to use the best available evidence on the treatment of DS-TB in order to inform policy decisions made in this technical area by national TB control programme managers, national policy-makers and medical practitioners in a variety of geographical, economic and social settings.

The objectives of the updated Guidelines are:

1) to provide updated recommendations based on newly emerged evidence on the treatment of drug-susceptible TB; and

For several decades the World Health Organization (WHO) developed and issued recommendations on the treatment of TB. The most recent WHO recommendations for treating people suffering from drug-susceptible TB (DS-TB) have been defined in the WHO's Guidelines for treatment of drug-susceptible tuberculosis and patient care, 2010 and 2017 updates [3, 4]. These guidelines focused on the 6-month treatment regimen composed of four first-line TB medicines, namely isoniazid, rifampicin, ethambutol and pyrazinamide, recommended for treatment of DS-TB.

Tuberculosis (TB) affects an estimated 10 million people per year (range 8.9-11.0 million) and is one of the world's leading infectious disease killers. TB is responsible for an estimated 1.2 million TB deaths among HIV-negative people (range, 1.1-1.3 million), and an additional 208 000 deaths among HIV-positive persons (range, 177 000-242 000). Of the estimated 10 million, approximately 70% are diagnosed and treated and also reported to the World Health Organization (WHO), resulting in 7.1 million TB notifications by National TB Programmes.

Drug-susceptible TB (DS-TB): A bacteriologically confirmed or clinically diagnosed case of TB without evidence of infection with strains resistant to rifampicin and isoniazid.

Drug susceptibility testing (DST): In vitro testing using either: 1) molecular, genotypic techniques to detect resistance-conferring mutations; or 2) phenotypic methods to determine susceptibility to a medicine.¹