TB and diabetes
The provision of integrated and patient-centred care for people with tuberculosis (TB) and comorbidities, including for those with diabetes mellitus, is embedded within Pillar 1 of the End TB Strategy. In 2018, at the first United Nations (UN) high-level meeting on TB, Member States committed to developing community-based health services with integrated care for TB patients with related health conditions; for example, HIV, undernutrition, mental illness, and noncommunicable diseases (NCDs), including diabetes mellitus (1).
The prevalence of diabetes influences TB incidence and TB mortality. It is associated with a twofold to threefold risk of TB disease, a twofold risk of death during TB treatment, a fourfold risk of TB relapse after treatment completion and a twofold risk of multidrug-resistant TB (MDR-TB) (2-4). In 2020, an estimated 370 000 (UI: 150 000 - 680 000) new cases of TB were attributable to diabetes (Section 6.3). In 2019, just over 15% of people with TB were estimated to have diabetes globally, compared with 9.3% among the general adult population (aged 20-79 years) (5, 6). This equates to about 1.5 million people with TB and diabetes who required coordinated care and follow-up to optimize the management of both conditions.
Global burden of diabetes
The Global Health Observatory provides national estimates of the prevalence of diabetes in adults (Fig. 1). The median prevalence of diabetes in the 30 high TB burden countries according to latest available data was 8% (Interquartile range [IQR]: 6-9%), and was 10% or more in Gabon (10%), Mongolia (12%), Pakistan (12%), Papua New Guinea (15%) and South Africa (11%) (Fig. 1). The International Diabetes Federation estimates that the number of people with diabetes will increase by about 50% globally between 2019 and 2045, with a median increase in the high TB burden countries of 99% (IQR: 69-151%) (6).
Collaborative action to address TB and diabetes
Since 2011, in recognition of the link between TB and diabetes, the World Health Organization (WHO) has recommended collaborative care for people with TB and diabetes in the Collaborative framework for care and control of TB and diabetes (7). The framework of recommendations is organized around three objectives: establish mechanisms for collaboration, detect and manage TB in patients with diabetes, and detect and manage diabetes in patients with TB (Table 1). Key components of the framework include surveillance of the joint burden of TB and diabetes, and monitoring and evaluation of collaborative TB and diabetes activities. WHO does not currently request countries to report routine data about the joint burden of TB and diabetes or the implementation of TB and diabetes collaborative activities. However, efforts are ongoing to assess the uptake of WHO policy and the joint burden of TB and diabetes.
To help with monitoring of progress in implementing people-centred care for TB and comorbidities since the UN high-level meeting on TB, WHO conducted a policy review in 2020. The review examined the extent to which national policies and guidelines in high TB burden countries aligned with WHO guidance for collaborative activities on TB and diabetes, and it focused on countries in the list of 30 high TB burden countries defined by WHO for 2016-2020. The review identified national TB strategic plans (NSPs) for all countries and 28 NSPs for NCDs, 55 national guidelines on TB (e.g. treatment guidelines, programmatic guidelines for the management of drug-resistant TB and the management of childhood TB), and three national frameworks for TB and diabetes. All documents were carefully reviewed to assess whether they described TB and diabetes collaborative activities. Based on this review, estimates were made of the number of countries adopting key recommendations on the screening and co-management of TB and diabetes within the respective NSPs for TB and NCDs, and within TB guidelines (Fig. 2).
Among the 30 high TB burden countries, 21 (70%) referred to the importance of TB screening among people with diabetes in at least one of their national documents. TB screening was featured in 18 (60%) NSPs for TB but was recommended in the national guidelines of only 15 (50%) countries. Overall, 20 (67%) countries referred to screening of diabetes in TB patients and 24 (80%) referred to management of diabetes in TB patients, but these topics had a limited profile in the NSPs for TB. Among the 24 (80%) countries that recommend diabetes management among people diagnosed with TB in their guidelines, nine (30% of the total) recommended it only for patients with MDR-TB. Only two (7%) countries (South Africa and United Republic of Tanzania) had plans for joint or bidirectional screening and co-management for TB and diabetes within their NSPs for NCDs.
Since 2017, countries in the WHO Region of the Americas have been asked to report on two indicators to monitor the burden of diabetes among people with a new or relapse episode of TB. These indicators are the number of TB patients tested for diabetes and the proportion of those tested who have diabetes. In 2020, 22 countries reported that they tested 47 041 people newly diagnosed with TB for diabetes, representing a median testing coverage rate of 55% (IQR: 13-92%). In the 13 countries that reported testing at least half of their TB patients for diabetes, the median diabetes prevalence was 13% (IQR: 11-20%).
These findings show that although WHO first recommended collaborative activities to address TB and diabetes in 2011, implementation is variable. Increased commitment to address the global burden of diabetes represents an opportunity for TB and NCD programmes to join forces to expand access to vital diagnosis and care necessary for people with TB and diabetes, and to optimize treatment outcomes (8). Monitoring and evaluation of the joint response will be critical for driving scale-up and for assessing the impact of TB and diabetes collaborative activities. Countries are urged to determine the impact of diabetes on the TB response, to implement TB and diabetes collaborative activities and to monitor their success as part of surveillance activities, operational research or prevalence surveys.
Fig. 1 The age-adjusted prevalence of diabetes, latest available dataa
Table 1. Activities outlined within the Collaborative framework for care and control of TB and diabetes
|
|---|
| A.1. Set up means of coordinating diabetes and TB activities |
| A.2. Conduct surveillance of TB disease prevalence among people with diabetes in medium and high-TB burden settings |
| A.3. Conduct surveillance of diabetes prevalence in TB patients in all countries |
| A.4. Conduct monitoring and evaluation of collaborative diabetes and TB activities |
|
| B.1. Intensify detection of TB among people with diabetes |
| B.2. Ensure TB infection control in health care settings where diabetes is managed |
| B.3. Ensure high-quality TB treatment and management in people with diabetes |
|
| C.1. Screen TB patients for diabetes |
| C.2. Ensure high-quality diabetes management among TB patients |
Fig. 2 Uptake of WHO recommendations on TB and diabetes by the 30 high TB burden countries in 2020
References
- United Nations General Assembly. Resolution 73/3: Political declaration of the high-level meeting of the General Assembly on the fight against tuberculosis. New York: United Nations; 2018 (https://www.un.org/en/ga/search/view_doc.asp?symbol=A/RES/73/3).
- Jeon CY, Murray MB. Diabetes mellitus increases the risk of active tuberculosis: a systematic review of 13 observational studies. PLoS Med. 2008;5(7):e152.
- Baker MA, Harries AD, Jeon CY, Hart JE, Kapur A, Lönnroth K et al. The impact of diabetes on tuberculosis treatment outcomes: a systematic review. BMC Med 2011; 9: 81.
- Liu Q, Li W, Xue M, Chen Y, Du X, Wang C et al. Diabetes mellitus and the risk of multidrug resistant tuberculosis: a meta-analysis. Scientific Reports. 2017;7(1):1–7.
- Noubiap JJ, Nansseu JR, Nyaga UF, Nkeck JR, Endomba FT, Kaze AD et al. Global prevalence of diabetes in active tuberculosis: a systematic review and meta-analysis of data from 2.3 million patients with tuberculosis. Lancet Glob Health 2019; 7: e448–60 (https://pubmed.ncbi.nlm.nih.gov/30819531/).
- IDF Diabetes Atlas, 9th edn. Brussels: International Diabetes Federation (IDF); 2019 (https://www.diabetesatlas.org).
- Collaborative framework for care and control of tuberculosis and diabetes. Geneva: World Health Organization; 2011 (https://apps.who.int/iris/bitstream/handle/10665/44698/9789241502252_eng.pdf).
- Reducing the burden of noncommunicable diseases through strengthening prevention and control of diabetes, Seventy-fourth World Health Assembly. A74/A/CONF./5 Agenda item 13.2, 24 May 2021. Geneva: World Health Assembly; 2021 (https://apps.who.int/gb/ebwha/pdf_files/WHA74/A74_R4-en.pdf).