Comorbidities

This section of the WHO operational handbook on tuberculosis. Module 6: tuberculosis and comorbidities was developed by Annabel Baddeley (WHO Global Tuberculosis Programme [GTB]) with support from Bianca Hemmingsen (Department of Noncommunicable Diseases, Rehabilitation and Disability) and Julia Critchley (consultant) with input from Anna Carlqvist, Kerri Viney, Matteo Zignol and Farai Mavhunga, all at the WHO GTB, and Slim Slama (Department of Noncommunicable Diseases, Rehabilitation and Disability), under the overall direction of Tereza Kasaeva, Director, WHO GTB.

1. Global tuberculosis report 2023. Geneva: World Health Organization; 2023 (https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2023, accessed 8 November 2023).
2. Framework for collaborative action on tuberculosis and comorbidities. Geneva: World Health Organization; 2022 (https://iris.who.int/handle/10665/361989, accessed 31 August 2023).
3. The end TB strategy.

Table A2.1 summarizes changes to recommendations published in the 2012 WHO policy on collaborative TB/HIV activities (1). The 2012 policy contained (i) WHO recommendations, which were formulated using the GRADE approach, and (ii) operational recommendations not assessed using the GRADE methodology, which were developed during consultation with key stakeholders.

Definitions of actions for changes to recommendations developed using the GRADE approach are as follows.

The formulation of WHO recommendations is based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. Once evidence has been synthesized through a systematic review approach, evidence reviewers use the GRADE methodology to categorize the quality of the evidence into four levels: high, moderate, low or very low (see Table A1.1). The starting point for rating the quality of evidence is always the study design, whereby evidence from RCTs is rated as high quality, while evidence from non-randomized or observational studies is rated as low quality.

Research gaps related to HIV-associated TB were identified during the respective GDG meetings and are listed below. Further research gaps, some of which may have already been addressed, can be found in Priority research questions for TB/HIV in HIV-prevalent and resource-limited settings (134).

Monitoring, evaluation and review provide the means to assess the quality, effectiveness, coverage and delivery of collaborative TB/HIV activities. It promotes a learning culture within and across programmes and ensures continuous improvement of interventions. Evidence from operational research (130, 131) has shown the importance of standardized monitoring and evaluation of collaborative TB/HIV activities to determine the impact of the activities and to ensure implementation and effective programme management.

3.3.1 Background

Whilst there are no recommendations on HIV prevention among people with presumptive and diagnosed TB that have been assessed using the GRADE methodology, programmatic guidance was developed as part of the development of the WHO policy on collaborative TB/HIV activities (10), as listed below in Box 3.1.