The association of hyperglycaemia with prevalent tuberculosis: a population-based cross-sectional study

The Effect of HIV on the Association of Hyperglycaemia and Active Tuberculosis in Zambia, a Case-Control Study

OBJECTIVES

To determine if HIV modifies the association between hyperglycaemia and active tuberculosis in Lusaka, Zambia.

METHODS

A case-control study among newly-diagnosed adult tuberculosis cases and population controls in three areas of Lusaka. Hyperglycaemia is determined by random blood glucose (RBG) concentration measured at the time of recruitment; active tuberculosis disease by clinical diagnosis, and HIV status by serological result. Multivariable logistic regression is used to explore the primary association and effect modification by HIV.

RESULTS

The prevalence of RBG concentration ≥ 11.1 mmol/L among 3843 tuberculosis cases was 1.4% and among 6977 controls was 1.5%. Overall, the adjusted odds ratio of active tuberculosis was 1.60 (95% CI 0.91-2.82) comparing those with RBG concentration ≥ 11.1- < 11.1 mmol/L. The corresponding adjusted odds ratio among those with and without HIV was 5.47 (95% CI 1.29-23.21) and 1.17 (95% CI 0.61-2.27) respectively; p-value for effect modification by HIV = 0.042. On subgroup analysis, the adjusted odds ratio of smear/Xpert-positive tuberculosis was 2.97 (95% CI 1.49-5.90) comparing RBG concentration ≥ 11.1- < 11.1 mmol/L.

CONCLUSIONS

Overall, no evidence of association between hyperglycaemia and active tuberculosis was found, though among those with HIV and/or smear/Xpert-positive tuberculosis there was evidence of association. Differentiation of hyperglycaemia caused by diabetes mellitus and stress-induced hyperglycaemia secondary to tuberculosis infection is important for a better understanding of these findings.

Prevalence and Associated Factors of Diabetes Mellitus Among Newly Enrolled Tuberculosis Patients in Lubumbashi (DRC)

Background

Tuberculosis and diabetes mellitus are major public health challenges worldwide. The two scourges have bidirectional relationship with high morbidity and mortality.

Objective

The present study was conducted to determine the prevalence of diabetes mellitus and identify related factors in patients with tuberculosis.

Methods

A cross-sectional study was conducted in 11 tuberculosis screening and treatment centers in Lubumbashi (DRC) from September to December 2022. Adult patient with a positive smear for tuberculosis were systematically screened for diabetes mellitus. Demographic characteristics, history and symptomatology were the variables of interest. Data was entered using Microsoft Excel software. STATA 16 software was used for analysis.

Results

A total of 255 tuberculosis patients were recruited and the prevalence of diabetes mellitus among these patients was 11.4% (ie, 29 out of 255). After uni and multivariate logistic regression, a BMI ≤ 18.5 Kg/m2, lack of employment, polyuria and intense thirst were the factors associated with diabetes mellitus in tuberculosis patients.

Conclusion

The prevalence of diabetes mellitus in smear positive tuberculosis patients in the present study was higher than the one observed in Central Africa.

Tuberculosis risk among people with diabetes mellitus in Sub-Saharan Africa: a systematic review

Objectives

People with diabetes mellitus (DM) have a higher tuberculosis (TB) risk, but the evidence from sub‐Saharan Africa (SSA) was scarce until recently and not included in earlier global summaries. Therefore, this systematic review aims to determine the risk of active TB disease among people with DM in SSA and whether HIV alters this association.

Methods

Medline, Embase, CINAHL, Web of Science, Global Health and African Index Medicus were searched between January 1980 and February 2021. Cohort, case‐control and cross‐sectional studies from SSA, which assessed the association between DM and active TB, were included if adjusted for age. Two researchers independently assessed titles, abstracts, full texts, extracted data and assessed the risk of bias. Estimates for the association between DM and TB were summarised using a random effects meta‐analysis. PROSPERO: CRD42021241743.

Results

Nine eligible studies were identified, which reported on 110,905 people from 5 countries. Individual study odds ratios (OR) of the TB–DM association ranged from 0.88 (95% CI 0.17–4.58) to 10.7 (95% CI 4.5–26). The pooled OR was 2.77 (95% CI 1.90–4.05). High heterogeneity was reduced in sensitivity analysis (from I² = 57% to I² = 6.9%), by excluding one study which ascertained DM by HbA1c. Risk of bias varied widely between studies, especially concerning the way in which DM status was determined.

Conclusions

There is a strong positive association between DM and active TB in SSA. More research is needed to determine whether HIV, a key risk factor for TB in SSA, modifies this relationship.

Mean platelet volume (MPV): new diagnostic indices for co-morbidity of tuberculosis and diabetes mellitus

Background

Tuberculosis (TB) and type 2 diabetes mellitus (DM) are global health diseases with high morbidity and mortality. Few studies have focused on platelet indices in TB-DM coinfection patients. The objective of this work was to analyze the platelet indices in TB, DM and TB-DM patients to assess the predictive value of the platelet index for the risk of these diseases.

Methods

In total, 246 patients admitted to our hospital were distributed into three groups (113TB, 59 DM and 74TB+DM). A total of 133 individuals were also recruited as healthy controls (HC). Platelet indices, namely, platelet count (PC), mean platelet volume (MPV), plateletcrit (PCT) and platelet distribution width (PDW), were compared among the four groups, and the relationship with inflammatory markers was explored by using statistical software.

Results

Our study discovered that MPV and PCT were significantly downregulated in TB+DM patients (9.951.25fL, 0.200.05%, P<0.0001, P=0.0121, separately) compared with DM individuals (10.921.17fL, 0.220.04%). Moreover, the changes in MPV were significantly higher in TB+DM patients (9.951.25fL, P=0.0041) than in TB patients (9.421.01fL). No differences were found in PLT and PDW among the four groups (P>0.05). The sensitivity and specificity of MPV in the differential diagnosis of DM patients vs TB+DM patients were 64.9 and 66.1% (P<0.0001), respectively, and the sensitivity and specificity of MPV between TB patients and TB+DM patients was 60.8 and 66.4%, respectively (P=0.003). MPV improved the diagnosis sensitivity when it was combined with clinical parameters, such as fasting blood glucose in DM and Mycobacterium tuberculosis culture result in TB (76.3% vs 64.9, 72.6% vs 60.8%, P<0.0001, P=0.001, respectively). In addition, the sensitivity and specificity of PCT in the differential diagnosis of DM patients vs TB+DM patients were 69.5 and 59.4%, respectively (P=0.008). PCT improved the diagnosis sensitivity when combined with fasting blood glucose in DM (72.9% vs 64.9%, P=0.004). In addition, MPV was linked to CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) in the TB+DM patients (r=0.3203, P=0.0054, r=0.2504, P=0.0307) but PCT was not (r=0.1905, r=0.008675, P>0.05, respectively).

Conclusions

Our research shows that MPV and PCT might be good clinical laboratory markers to distinguish TB+DM patients from TB or DM individuals, thus providing support for earlier clinical diagnosis, prevention, and therapy.

Changes in Host Response to Mycobacterium tuberculosis Infection Associated With Type 2 Diabetes: Beyond Hyperglycemia

Tuberculosis (TB) remains as the first cause of death among infectious diseases worldwide. Global incidence of tuberculosis is in part coincident with incidence of type 2 diabetes (T2D). Incidence of T2D is recognized as a high-risk factor that may contribute to tuberculosis dissemination. However, mechanisms which favor infection under T2D are just starting to emerge. Here, we first discuss the evidences that are available to support a metabolic connection between TB and T2D. Then, we analyze the evidences of metabolic changes which occur during T2D gathered thus far for its influence on susceptibility to M. tuberculosis infection and TB progression, such as hyperglycemia, increase of 1AC levels, increase of triglycerides levels, reduction of HDL-cholesterol levels, increased concentration of lipoproteins, and modification of the activity of some hormones related to the control of metabolic homeostasis. Finally, we recognize possible advantages of metabolic management of immunity to develop new strategies for treatment, diagnosis, and prevention of tuberculosis.

The epidemiology of intransient TB-induced hyperglycaemia in previously undiagnosed diabetes mellitus 2 individuals: a protocol for a systematic review and meta-analysis

BACKGROUND

Diabetes mellitus (DM) is burgeoning as a global chronic health condition. Some studies suggest that tuberculosis (TB) can even cause diabetes in those not previously known to be diabetic, which as a corollary can add to the already heavy global DM burden. The World Health Organization (WHO) recommends screening for DM at the start of TB treatment; however, it remains to be elucidated which patients with TB-induced hyperglycaemia are at risk for developing DM and who would benefit from a more regular follow-up. This systematic review will aim to firstly synthesise literature on the irreversibility of TB-induced hyperglycaemia in individuals with previously undiagnosed type 2 diabetes mellitus and secondly to synthesise literature on risk factors for progression from TB-induced hyperglycaemia to overt DM in previously undiagnosed.

METHODS

We will search for relevant studies in electronic databases such as PubMed, EMBASE, PROQUEST, and SCOPUS. Furthermore, references will be hand searched to identify other studies. A flow diagram will be drawn to identify the studies retrieved from each database. We will review all publications that include studies containing data on impaired glucose metabolism upon TB diagnosis, and the quality of all eligible studies will be assessed using the Newcastle-Ottawa Scale. We will further conduct a meta-analysis to pool estimates on the risk of progression of persistent hyperglycaemia to overt DM within this population group, as well as the risk factors for this progression. We will use a random effect model to assess heterogeneity, will carry out sensitivity analysis to explore the influence of a single study on the overall estimate, and will report our findings from our systematic review and meta-analysis according to PRISMA guidelines. Egger's test will be performed to explore the presence of selective reporting bias. If data allow, we will perform a subgroup/meta-regression analysis. Summary effects will be reported using odds ratio, hazard ratio, and relative risk ratios. Furthermore, any clinical, epidemiological, and public health research gaps we identify will be described in a research proposal.

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.

Metformin is associated with a lower risk of active tuberculosis in patients with type 2 diabetes

BACKGROUND AND OBJECTIVE

Metformin is an oral anti-diabetic therapy (ADT) to manage type 2 diabetes mellitus (T2DM), and has been reported to have potential anti-tuberculosis (TB) effects. This study investigates the risk of active TB among persons with T2DM who were treated with various ADT and insulin therapies.

METHODS

We conducted a nationwide population-based cohort study using the Taiwan Longitudinal Health Insurance Database, including 49 028 T2DM patients who were metformin users (n = 44 002) or non-users (n = 5026). A total of 5026 propensity score-matched pairs of metformin users and non-users with T2DM were evaluated from 1998 to 2010. The data were analysed using Cox proportional hazard models.

RESULTS

Patients with T2DM had a significantly higher rate of incident TB than did the control subjects (adjusted hazard ratio: 2.01; 95% confidence interval (95% CI): 1.80-2.25). After adjusting for comorbidities, diabetes complications, ADT type and statin use, metformin use was an independent factor for predicting a reduced risk of active TB (adjusted relative risk (aRR): 0.24; 95% CI: 0.18-0.32). The association between metformin use and active TB risk was also consistent in most subgroup analyses, except for patients with metabolic disorders (aRR: 0.46; 95% CI: 0.11-1.87). This protective effect of metformin was dose-dependent but diminished gradually in the elderly population.

CONCLUSION

Among all types of ADT and insulin therapies, metformin is the only agent with a decreased risk of active TB in the T2DM population. However, this effect was diminished in the elderly population and was not observed in patients with metabolic disorders.

Socio-economic gradients in prevalent tuberculosis in Zambia and the Western Cape of South Africa

Objective

To describe the associations between socio‐economic position and prevalent tuberculosis in the 2010 ZAMSTAR Tuberculosis Prevalence Survey, one of the first large tuberculosis prevalence surveys in Southern Africa in the HIV era.

Methods

The main analyses used data on 34 446 individuals in Zambia and 30 017 individuals in South Africa with evaluable tuberculosis culture results. Logistic regression was used to estimate adjusted odds ratios for prevalent TB by two measures of socio‐economic position: household wealth, derived from data on assets using principal components analysis, and individual educational attainment. Mediation analysis was used to evaluate potential mechanisms for the observed social gradients.

Results

The quartile with highest household wealth index in Zambia and South Africa had, respectively, 0.55 (95% CI 0.33–0.92) times and 0.70 (95% CI 0.54–0.93) times the adjusted odds of prevalent TB of the bottom quartile. College or university‐educated individuals in Zambia and South Africa had, respectively, 0.25 (95% CI 0.12–0.54) and 0.42 (95% CI 0.25–0.70) times the adjusted odds of prevalent TB of individuals who had received only primary education. We found little evidence that these associations were mediated via several key proximal risk factors for TB, including HIV status.

Conclusion

These data suggest that social determinants of TB remain important even in the context of generalised HIV epidemics.

Screening for Diabetes Mellitus among Tuberculosis Patients: Findings from a Study at a Tertiary Hospital in Lusaka, Zambia

BACKGROUND

Diabetes mellitus (DM) is known to be associated with active tuberculosis (TB). Zambia is a low-income sub-Saharan African country with a high TB burden and increasing numbers of newly diagnosed DM patients.

MATERIALS AND METHODS

This was an observational study conducted at the University Teaching Hospital in Lusaka, Zambia, from October 2014 to February 2016. Adult patients with active TB were screened for DM.

RESULTS

A total of 127 individuals were enrolled in the study. Six patients (5%) were found to have diabetes. Of these, three had a prior diagnosis of diabetes and were on medication while three were newly diagnosed. Low education level was significantly associated with DM (p=0.001; 95% CI 0.001-0.148).

CONCLUSION

The prevalence of DM among individuals with smear positive TB in our study population was similar to that of the general population in Zambia.

Hyperglycemia during tuberculosis treatment increases morbidity and mortality in a contemporary cohort of HIV-infected patients in Rio de Janeiro, Brazil

BACKGROUND

Hyperglycemia occurs in tuberculosis (TB), but the long-term impact is unknown. We estimated the prevalence of hyperglycemia and compared the TB treatment outcomes and 1-year mortality rate according to the glycemic status noted during TB treatment.

METHODS

We conducted a retrospective cohort analysis of adult patients who had TB and HIV coinfection and started receiving TB treatment at the Instituto Nacional de Infectologia Evandro Chagas, Brazil, between 2010-2015. Diabetes Mellitus (DM) and hyperglycemia were defined according to the American Diabetes Association. After excluding for known DM at baseline, the proportion of participants who developed new-onset DM after TB treatment was assessed. TB outcome was classified as successful or adverse (i.e., treatment failure, abandonment, and death). Kaplan-Meier survival curves were compared by the log-rank test based on the glycemic status of patients. Multivariate Cox regression models were used to assess the association between hyperglycemia and 1-year mortality. Two-sided p values <0.05 were considered statistically significant.

RESULTS

We identified 414 euglycemic patients (87.5%), 49 hyperglycemic patients (10.3%), and 10 patients with known DM (2.1%). Diabetic patients were older compared to the euglycemic and hyperglycemic patients (47.9 vs. 37 vs. 39.7 years, respectively, p=0.001). Diabetic patients frequently had cavitation on chest image compared to hyperglycemic and euglycemic patients (50% vs. 23.4% vs. 15.3%, p=0.007, respectively). Hyperglycemic patients had more new-onset DM at follow-up compared to euglycemic (22 vs. 1; p<0001). Hyperglycemia was associated with adverse outcomes (71.4% vs. 24.6%, p<0.0001) compared to euglycemia. Crude 1-year mortality was significantly higher in patients with hyperglycemia compared with euglycemia (48.9% vs. 7.9%; unadjusted HR: 5.79 (3.74-8.96)). In the adjusted Cox models, hyperglycemia remained a significant factor for increased 1-year mortality (adjusted HR: 3.72 (2.17-6.38)].

CONCLUSIONS

Hyperglycemia frequently occurs in HIV-infected patients who commence TB treatment, and it increases the risks of adverse TB outcomes and 1-year mortality. Glucose testing during TB treatment detects patients at risk of adverse outcomes.

Glucagon and glucagon-like peptide-1 as novel anti-inflammatory and immunomodulatory compounds

Glucagon and glucagon-like peptide-1 (GLP-1) are polypeptide hormones that are produced by pancreatic α-cells and the intestine, respectively, whose main function is to control glucose homeostasis. The glucagon and GLP-1 levels are imbalanced in diabetes. Furthermore, type 1 diabetic patients and animals present with a diminished inflammatory response, which is related to some morbidities of diabetes, such as a higher incidence of infectious diseases, including sepsis. The focus of this review is to briefly summarize the state of the art concerning the effects of glucagon and GLP-1 on the inflammatory response. Here, we propose that glucagon and GLP-1 have anti-inflammatory properties, making them possible prototypes for the design and synthesis of new compounds to treat inflammatory diseases. In addition, glucagon, GLP-1 or their analogues or new derivatives may not only be important for managing inflammatory diseases but may also have the therapeutic potential to prevent, cure or ameliorate diabetes in patients by counteracting the deleterious effects of pro-inflammatory cytokines on the function and viability of pancreatic β-cells. In addition, GLP-1, its analogues or drugs that inhibit GLP-1 metabolism may have a doubly beneficial effect in diabetic patients by inhibiting the inflammatory response and reducing glycaemia.