Screening for active tuberculosis in a diabetes mellitus clinic in Soweto, South Africa

Number needed to screen for TB in clinical, structural or occupational risk groups

BACKGROUND: Screening for active TB using active case-finding (ACF) may reduce TB incidence, prevalence, and mortality; however, yield of ACF interventions varies substantially across populations. We systematically reviewed studies reporting on ACF to calculate the number needed to screen (NNS) for groups at high risk for TB.METHODS: We conducted a literature search for studies reporting ACF for adults published between November 2010 and February 2020. We determined active TB prevalence detected through various screening strategies and calculated crude NNS for - TB confirmed using culture or Xpert^® MTB/RIF, and weighted mean NNS stratified by screening strategy, risk group, and country-level TB incidence.RESULTS: We screened 27,223 abstracts; 90 studies were included (41 in low/moderate and 49 in medium/high TB incidence settings). High-risk groups included inpatients, outpatients, people living with diabetes (PLWD), migrants, prison inmates, persons experiencing homelessness (PEH), healthcare workers, and miners. Screening strategies included symptom-based screening, chest X-ray and Xpert testing. NNS varied widely across and within incidence settings based on risk groups and screening methods. Screening tools with higher sensitivity (e.g., Xpert, CXR) were associated with lower NNS estimates.CONCLUSIONS: NNS for ACF strategies varies substantially between adult risk groups. Specific interventions should be tailored based on local epidemiology and costs.

Screening diabetes mellitus patients for pulmonary tuberculosis: a multisite study in Indonesia, Peru, Romania and South Africa

BACKGROUND

Diabetes mellitus (DM) patients are three times more likely to develop tuberculosis (TB) than the general population. Active TB screening in people with DM is part of a bidirectional approach. The aim of this study was to conduct pragmatic active TB screening among DM patients in four countries to inform policy.

METHODS

DM patients were recruited in Indonesia (n=809), Peru (n=600), Romania (n=603) and South Africa (n=51). TB cases were diagnosed using an algorithm including clinical symptoms and chest X-ray. Presumptive TB patients were examined with sputum smear and culture.

RESULTS

A total of 171 (8.3%) individuals reported ever having had TB (South Africa, 26%; Indonesia, 12%; Peru, 7%; Romania, 4%), 15 of whom were already on TB treatment. Overall, 14 (0.73% [95% confidence interval 0.40 to 1.23]) TB cases were identified from screening. Poor glucose control, smoking, lower body mass index, education and socio-economic status were associated with newly diagnosed/current TB. Thirteen of the 14 TB cases diagnosed from this screening would have been found using a symptom-based approach.

CONCLUSIONS

These data support the World Health Organization recommendation for routine symptom-based screening for TB in known DM patients in high TB-burden countries. DM patients with any symptoms consistent with TB should be investigated and diagnostic tools should be easily accessible.

The Interaction of Diabetes and Tuberculosis: Translating Research to Policy and Practice

Diabetes Mellitus increases the risk of developing Tuberculosis (TB) disease by about three times; it also doubles the risk of death during TB treatment and other poor TB treatment outcomes. Diabetes may increase the risk of latent infection with Mycobacterium tuberculosis (LTBI), but the magnitude of this effect is less clear. Whilst this syndemic has received considerable attention, most of the published research has focussed on screening for undiagnosed diabetes in TB patients or observational follow-up of TB treatment outcomes by diabetes status. There are thus substantial research and policy gaps, particularly with regard to prevention of TB disease in people with diabetes and management of patients with TB-diabetes, both during TB treatment and after successful completion of TB treatment, when they likely remain at high risk of TB recurrence, mortality from TB and cardiovascular disease. Potential strategies to prevent development of TB disease might include targeted vaccination programmes, screening for LTBI and preventive therapy among diabetes patients or, perhaps ideally, improved diabetes management and prevention. The cost-effectiveness of each of these, and in particular how each strategy might compare with targeted TB prevention among other population groups at higher risk of developing TB disease, is also unknown. Despite research gaps, clinicians urgently need practical management advice and more research evidence on the choice and dose of different anti-diabetes medication and effective medical therapies to reduce cardiovascular risks (statins, anti-hypertensives and aspirin). Substantial health system strengthening and integration may be needed to prevent these at risk patients being lost to care at the end of TB treatment.

Coprevalence of type 2 diabetes mellitus and tuberculosis in low-income and middle-income countries: A systematic review

Increasing coprevalence of diabetes mellitus (DM) and tuberculosis (TB) in low-income and middle-income countries (LMICs) indicates a rising threat to the decades of progress made against TB and requires global attention. This systematic review provides a summary of type 2 diabetes and tuberculosis coprevalence in various LMICs. We searched PubMed, Ovid Medline, Embase, and PsychINFO databases for studies that provided estimates of TB-DM coprevalence in LMICs published between 1990 and 2016. Studies that were non-English and exclusively conducted in multidrug resistant-tuberculosis or type 1 diabetes and inpatient settings were excluded. We reviewed 84 studies from 31 countries. There were huge diversity of study designs and diagnostic methods used to estimate coprevalence, and this precluded pooling of the results. Most studies (n = 78) were from small, localized settings. The DM prevalence among TB patients in various LMICs varied from 1.8% to 45%, with the majority (n = 44) between 10% and 30%. The TB prevalence among people with DM ranged from 0.1% to 6.0% with most studies (n = 9) reporting prevalences less than 2%. Coprevalence of TB-DM was higher than general population prevalence of either diseases in these countries. This study underscores the need for intervention and more focused research on TB DM bidirectional screening programs in low-income and middle-income countries as well as integrated chronic disease management.

The prevalence and determinants of active tuberculosis among diabetes patients in Cape Town, South Africa, a high HIV/TB burden setting

AIMS

Studies addressing the association between diabetes mellitus (DM) and tuberculosis (TB) in sub-Saharan Africa are limited. We assessed the prevalence of active TB among DM patients at a primary care clinic, and identified risk factors for prevalent TB.

METHODS

A cross-sectional study was conducted in adult DM patients attending a clinic in Khayelitsha, Cape Town. Participants were screened for active TB (symptom screening and microbiological diagnosis) and HIV.

RESULTS

Among 440 DM patients screened, the active TB prevalence was 3.0% (95% CI 1.72-5.03). Of the 13 prevalent TB cases, 53.9% (n = 7; 95% CI 27.20-78.50) had no TB symptoms, and 61.5% (n = 8; 95% CI 33.30-83.70) were HIV-1 co-infected. There were no significant differences in either fasting plasma glucose or HbA_1c levels between TB and non-TB participants. On multivariate analysis, HIV-1 infection (OR 11.3, 95% CI 3.26-39.42) and hemoptysis (OR 31.4, 95% CI 3.62-273.35) were strongly associated with prevalent active TB, with no differences in this association by age or gender.

CONCLUSIONS

The prevalence of active TB among DM patients was 4-fold higher than the national prevalence; suggesting the need for active TB screening, particularly if hemoptysis is reported. Our results highlight the importance of HIV screening in this older population group. The high prevalence of sub-clinical TB among those diagnosed with TB highlights the need for further research to determine how best to screen for active TB in high-risk TB/HIV population groups and settings.

Tuberculosis screening among persons with diabetes mellitus in Pune, India

BACKGROUND

Diabetes mellitus (DM) increases tuberculosis (TB) risk, and there is increasing concern over the public health implications of the convergence of these two epidemics. Screening for TB among people with DM is now recommended in India.

METHODS

People with DM seeking care at a large public sector tertiary care hospital clinic in Pune, India, were screened for TB from June 2015 to May 2016. All consenting people with DM were screened for TB at each clinic visit using a five-item, WHO-recommended questionnaire and those with TB symptoms and/or risk factors were tested for active TB using sputum smear microscopty, Xpert® MTB/RIF and TB culture. Categorical data and continuous variables were summarized using descriptive statistics. The x ² test or Wilcoxon rank-sum test was used to ascertain significant associations between categorical and continuous variables, respectively.

RESULTS

Among 630 adults approached for screening, median age was 60 (interquartile range (IQR), 57-64) years and 350 (56%) were females. Median hemoglobin A1c (HbA1c) was 8.7% (IQR, 6.7-9.9) and 444 (70.5%) were poorly controlled DM (HbA1c > 7). Forty-four (7%) had prior history of TB but the proportion with TB risk factors at screening was low (<5%). While 18% of participants reported any TB symptoms, none of these patients were diagnosed with culture confirmed TB.

CONCLUSIONS

Our study failed to yield any active TB cases using a WHO-recommended questionnaire among people with DM. High TB risk populations among people with DM must be identified if TB screening is to be feasible in settings such as India where the DM epidemic continues to rise.