Tuberculosis and diabetes in southern Mexico

Clinical characteristics, drug resistance, and treatment outcomes among tuberculosis patients with diabetes in Peru

OBJECTIVES

Diabetes is a risk factor for active tuberculosis (TB). Data are limited regarding the association between diabetes and TB drug resistance and treatment outcomes. We examined characteristics of TB patients with and without diabetes in a Peruvian cohort at high risk for drug-resistant TB. Among TB patients with diabetes (TB-DM), we studied the association between diabetes clinical/management characteristics and TB drug resistance and treatment outcomes.

METHODS

During 2005-2008, adults with suspected TB with respiratory symptoms in Lima, Peru, who received rapid drug susceptibility testing (DST), were prospectively enrolled and followed during treatment. Bivariate and Kaplan-Meier analyses were used to examine the relationships of diabetes characteristics with drug-resistant TB and TB outcomes.

RESULTS

Of 1671 adult TB patients enrolled, 186 (11.1%) had diabetes. TB-DM patients were significantly more likely than TB patients without diabetes to be older, have had no previous TB treatment, and to have a body mass index (BMI) >18.5 kg/m(2) (p<0.05). In patients without and with previous TB treatment, the prevalence of multidrug-resistant TB was 23% and 26%, respectively, among patients without diabetes, and 12% and 28%, respectively, among TB-DM patients. Among 149 TB-DM patients with DST results, 104 (69.8%) had drug-susceptible TB and 45 (30.2%) had drug-resistant TB, of whom 29 had multidrug-resistant TB. There was no association between diabetes characteristics and drug-resistant TB. Of 136 TB-DM patients with outcome information, 107 (78.7%) had a favorable TB outcome; active diabetes management was associated with a favorable outcome.

CONCLUSIONS

Diabetes was common in a cohort of TB patients at high risk for drug-resistant TB. Despite prevalent multidrug-resistant TB among TB-DM patients, the majority had a favorable TB treatment outcome.

Managing tuberculosis in patients with diabetes mellitus: why we care and what we know

As the global prevalence of diabetes mellitus (DM) increases, especially in low-to-middle income countries where tuberculosis (TB) remains endemic, we will encounter a growing number of TB patients with DM. This is a major concern for TB control programs, clinicians and patients alike because DM patients are at an increased risk of TB and are more likely to face poor TB treatment outcomes, including treatment failure, relapse and even death. Priority should be placed on early detection of both diseases through active screening, monitoring of adherence to medications for both diseases, and integration of TB and DM management strategies that would facilitate the provision of more comprehensive services that TB patients with DM require.

Prevalence of diabetes and metabolic syndrome in a migrant Mixtec population, Baja California, Mexico

This study was conducted to determine the prevalence and correlates of metabolic syndrome (MS) and diabetes among a migrant Mixtec population residing in San Quintin, Baja California, Mexico. A cross-sectional study utilizing data collected during a 2-day clinic in 2008 in a rural farming community with a high prevalence of Mixtec Indians. Interviews and clinical examinations were performed to assess sociodemographic data, medical history and anthropometric measures. Blood samples were obtained to measure glycated hemoglobin, fasting glucose, triglycerides, total cholesterol, HDL and LDL. Of the 107 patients surveyed, 56 % were female and mean age was 38.5 (range: 18-74, SD = 12.6) years. Overall, 41.1 % had MS and 26.2 % had diabetes. Drinking alcohol more than once a week [adjusted OR (AOR) = 16.0, p = 0.008] and being literate (AOR = 0.38, p = 0.035) were independently associated with MS. Only female gender was significantly associated with diabetes (OR = 3.95, p = 0.005). The high prevalence of MS, diabetes and other metabolic abnormalities among migrant farm workers in San Quintin suggest the need for interventions to reduce the risk for these conditions.

Association of diabetes and tuberculosis: impact on treatment and post-treatment outcomes

Objective

To determine the clinical consequences of pulmonary tuberculosis (TB) among patients with diabetes mellitus (DM).

Methods

We conducted a prospective study of patients with TB in Southern Mexico. From 1995 to 2010, patients with acid-fast bacilli or Mycobacterium tuberculosis in sputum samples underwent epidemiological, clinical and microbiological evaluation. Annual follow-ups were performed to ascertain treatment outcome, recurrence, relapse and reinfection.

Results

The prevalence of DM among 1262 patients with pulmonary TB was 29.63% (n=374). Patients with DM and pulmonary TB had more severe clinical manifestations (cavities of any size on the chest x-ray, adjusted OR (aOR) 1.80, 95% CI 1.35 to 2.41), delayed sputum conversion (aOR 1.51, 95% CI 1.09 to 2.10), a higher probability of treatment failure (aOR 2.93, 95% CI 1.18 to 7.23), recurrence (adjusted HR (aHR) 1.76, 95% CI 1.11 to 2.79) and relapse (aHR 1.83, 95% CI 1.04 to 3.23). Most of the second episodes among patients with DM were caused by bacteria with the same genotype but, in 5/26 instances (19.23%), reinfection with a different strain occurred.

Conclusions

Given the growing epidemic of DM worldwide, it is necessary to add DM prevention and control strategies to TB control programmes and vice versa and to evaluate their effectiveness. The concurrence of both diseases potentially carries a risk of global spreading, with serious implications for TB control and the achievement of the United Nations Millennium Development Goals.

Quantifying the association between tuberculosis and diabetes in the US: a case-control analysis

Historically, an association between tuberculosis and diabetes was recognised clinically, and the recent global rise in diabetes prevalence has reignited interest. We therefore quantified the tuberculosis-diabetes association using US survey data. A case-control analysis was performed using cross-sectional data from the second National Health and Nutrition Examination Survey (1976-1980; civilian non-institutionalised US population aged 20-74). Cases were respondents ever diagnosed with tuberculosis, and controls were respondents who reported never receiving a tuberculosis diagnosis. Exposure to diabetes and intermediate hyperglycaemia was defined using a self-reported measure, an oral glucose tolerance test, or both. We used logistic regression to estimate an adjusted odds ratio, controlling for potential major confounders. In relation to the main exposure measure, the adjusted odds ratio for the association between tuberculosis and diabetes varied between 2.31 (95% confidence interval 1.36-3.93) and 2.36 (95% confidence interval 1.40-3.97), depending on the model. No association was found for intermediate hyperglycaemia, with adjusted odds ratio varying between 1.33 (95% confidence interval 0.49-3.64) and 1.34 (95% confidence interval 0.50-3.62), depending on model. Irrespective of the exposure measure and the confounders controlled for, diabetes was associated with an increased tuberculosis risk. This study may underestimate the true association due to exposure misclassification.

Relationship between hepatitis C virus infection and type 2 diabetes mellitus: meta-analysis

AIM

To investigate the association between hepatitis C infection and type 2 diabetes mellitus.

METHODS

Observational studies assessing the relationship between hepatitis C infection and type 2 diabetes mellitus were identified via electronic and hand searches. Studies published between 1988 to March 2011 were screened, according to the inclusion criteria set for the present analysis. Authors performed separate analyses for the comparisons between hepatitis C virus (HCV) infected and not infected, and HCV infected and hepatitis B virus infected. The included studies were further subgrouped according to the study design. Heterogenity was assessed using I(2) statistics. The summary odds ratios with their corresponding 95% CIs were calculated based on a random-effects model. The included studies were subgrouped according to the study design. To assess any factor that could potentially affect the outcome, results were further stratified by age group (proportion of ≥ 40 years), gender (proportion of male gender), body mass index (BMI) (proportion of BMI ≥ 27), and family history of diabetes (i.e., self reported). For stability of results, a sensitivity analysis was conducted including only prospective studies.

RESULTS

Combining the electronic database and hand searches, a total of 35 observational studies (in 31 articles) were identified for the final analysis. Based on random-effects model, 17 studies (n = 286,084) compared hepatitis C-infected patients with those who were uninfected [summary odds ratio (OR): 1.68, 95% CI: 1.15-2.45]. Of these 17 studies, 7 were both a cross-sectional design (41.2%) and cohort design (41.2%), while 3 were case-control studies (17.6%). Nineteen studies (n = 51,156) compared hepatitis C-infected participants with hepatitis B-infected (summary OR: 1.92, 95% CI: 1.41-2.62). Of these 19 studies, 4 (21.1%), 6 (31.6%) and 9 (47.4%) were cross-sectional, cohort and case-control studies, respectively. A sensitivity analysis with 3 prospective studies indicated that hepatitis C-infected patients had a higher risk of developing type 2 diabetes compared with uninfected controls (summary odds ratio: 1.41, 95% CI: 1.17-1.7; I(2) = 0%). Among hepatitis C-infected patients, male patients (OR: 1.26, 95% CI: 1.03-1.54) with age over 40 years (summary OR: 7.39, 95% CI: 3.82-9.38) had an increased frequency of type 2 diabetes. Some caution must be taken in the interpretation of these results because there may be unmeasured confounding factors which may introduce bias.

CONCLUSION

The findings support the association between hepatitis C infection and type 2 diabetes mellitus. The direction of association remains to be determined, however. Prospective studies with adequate sample sizes are recommended.

Risk of tuberculosis among people with diabetes mellitus: an Australian nationwide cohort study

OBJECTIVE

Previous studies that have found an increased risk for tuberculosis (TB) in people with diabetes mellitus (DM) have been conducted in segments of the population and have not adjusted for important potential confounders. We sought to determine the RR for TB in the presence of DM in a national population with data on confounding factors in order to inform the decision-making process about latent tuberculosis infection (LTBI) screening in people with diabetes.

DESIGN

Whole population historical cohort study.

SETTING

All Australian States and Territories with a mean TB incidence of 5.8/100 000.

PARTICIPANTS

Cases of TB in people with DM were identified by record linkage using the National Diabetes Services Scheme Database and TB notification databases for the years 2001-2006.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary outcome was notified cases of TB. Secondary outcome was notified cases of culture-confirmed TB. RR of TB was estimated with adjustment for age, sex, TB incidence in country of birth and indigenous status.

RESULTS

There were 6276 cases of active TB among 19 855 283 people living in Australia between 2001 and 2006. There were 271 (188 culture positive) cases of TB among 802 087 members of the DM cohort and 130 cases of TB among 273 023 people using insulin. The crude RR of TB was 1.78 (95% CI 1.17 to 2.73) in all people with DM and 2.16 (95% CI 1.19 to 3.93) in people with DM using insulin. The adjusted RRs were 1.48 (95% CI 1.04 to 2.10) and 2.27 (95% CI 1.41 to 3.66), respectively.

CONCLUSIONS

The presence of DM alone does not justify screening for LTBI. However, when combined with other risk factors for TB, the presence of DM may be sufficient to justify screening and treatment for LTBI.

The co-management of tuberculosis and diabetes: challenges and opportunities in the developing world

Yanis Ben Amor and Timothy Sullivan call for more research to examine whether the diagnosis and treatment of diabetes in TB patients may improve TB outcomes and patient survival.

Importance of differentiating Mycobaterium bovis in tuberculous meningitis

The aim of the article is to describe the principal findings among patients with M.tuberculosis and M. bovis CNS infection. Mycobacterium tuberculosis is one of the most common infectious agents that cause death and neurological sequelae around the world. Most of the complications of CNS TB can be attributed to a delay in the diagnosis. Unfortunately, there are no specific diagnostic tools to support an early diagnosis. Other prognostic factors different from delay in treatment have not been identified. Clinical, radiological and laboratory characteristics were analyzed retrospectively from the medical files of all the patients admitted with the diagnoses of tuberculosis. Of 215 patients admitted with systemic tuberculosis, 64 (30%) had a neurological infection. Positive cultures were found in 54 (84%) cases, 18 (33%) in the CSF and the rest in other fluids or tissues. Adenosin deaminase (ADA) enzyme determination was more sensitive than M. tuberculosis PCR in the CSF for supporting an early diagnosis. In addition to a later clinical stage and treatment lag, positive CSF cultures (P=0.001) and the presence of M. bovis (P=0.020) were prognostic factors for a worse outcome. Neither older age, the presence of tuberculomas versus meningeal enhancement, or HIV co-infection, was associated to a worse prognosis. The isolation of M. bovis subspecies was more common that previously reported, and it was associated to the development of parenchymal lesions (P=0.032) when compared to M. tuberculosis. In this study, positive CSF cultures for M. tuberculosis and further identifying M. bovis species were additional prognostic factors for worse outcome. Positive cultures in systemic fluids other than CSF, even when the patient had no obvious systemic manifestations, and ADA determination in the CSF were noteworthy diagnostic tools for the diagnosis.

Effect of age on presentation with diabetes: Comparison of nondiabetic patients with new smear-positive pulmonary tuberculosis patients

Background:

Diabetes mellitus (DM) has been reported to modify the presenting features of pulmonary tuberculosis (PTB), but data regarding the effect of diabetes on the presentation of PTB are highly variable.

Objective:

To determine whether DM alters the demographic, clinical, and radiological manifestations of tuberculosis and whether the effect of diabetes varies with the age group of PTB patients.

Materials and Methods :

This prospective observational study was conducted on new smear-positive PTB patients with DM (PTB-DM group) and non-diabetic PTB patients (PTB group). Patients of both groups were again divided into six age groups (15–29, 30–39, 40–49, 50–59, 60–69, and >70 rears) to analyze and compare the impact of age on clinicoradiological presentations of PTB.

Results:

Patients in the PTB-DM group were significantly older (53.34 ± 14.06 year) in comparison to their nondiabetic counterparts (PTB group) (44.35 ± 18.14 year) (P < 0.001). The former group also had a lower male:female ratio, although the difference was not statistically significant (1.16:1 vs. 2.05:1, P = 0.101). Tuberculin positivity was significantly higher in the PTB group, compared with patients in the PTB-DM group (P < 0.004). The proportion of patients with lower lung field involvement (P = 0.003) and cavitations (P = 0.005) was also higher in the former group compared with the latter.

Conclusion:

Diabetic patients with tuberculosis were relatively older, had lower tuberculin positivity, and higher proportion of lower lung field involvement and cavitation in comparison to nondiabetic patients.

Implications of the global increase of diabetes for tuberculosis control and patient care

OBJECTIVES

To review the current knowledge about tuberculosis (TB) and diabetes, assessing the implication of the global increase of diabetes for TB control and patient care.

METHODS

Systematic literature review.

RESULTS

Using public databases, it can be estimated that 12.6% (95% CI 9.2-17.3%) of new TB cases in the 10 countries with the highest TB burden will be attributable to TB in 2030, a relative increase of 25.5% compared to 2010. Diabetes is associated with a higher age and body weight among patients with TB, but probably not with a specific clinical presentation of TB. Rifampicin hampers glycemic control by increasing the metabolism of most oral antidiabetic drugs, while diabetes patients may have lower concentrations of anti-TB drugs. This might be one factor contributing to higher TB treatment failure rates.

CONCLUSIONS

The global epidemic of diabetes has implications for control and treatment of TB. Prospective studies are needed to improve prevention, early detection and treatment of concomitant diabetes and TB, especially in developing countries.

Diabetes in Sub Saharan Africa 1999-2011: epidemiology and public health implications. A systematic review

Background

Diabetes prevalence is increasing globally, and Sub-Saharan Africa is no exception. With diverse health challenges, health authorities in Sub-Saharan Africa and international donors need robust data on the epidemiology and impact of diabetes in order to plan and prioritise their health programmes. This paper aims to provide a comprehensive and up-to-date review of the epidemiological trends and public health implications of diabetes in Sub-Saharan Africa.

Methods

We conducted a systematic literature review of papers published on diabetes in Sub-Saharan Africa 1999-March 2011, providing data on diabetes prevalence, outcomes (chronic complications, infections, and mortality), access to diagnosis and care and economic impact.

Results

Type 2 diabetes accounts for well over 90% of diabetes in Sub-Saharan Africa, and population prevalence proportions ranged from 1% in rural Uganda to 12% in urban Kenya. Reported type 1 diabetes prevalence was low and ranged from 4 per 100,000 in Mozambique to 12 per 100,000 in Zambia. Gestational diabetes prevalence varied from 0% in Tanzania to 9% in Ethiopia. Proportions of patients with diabetic complications ranged from 7-63% for retinopathy, 27-66% for neuropathy, and 10-83% for microalbuminuria. Diabetes is likely to increase the risk of several important infections in the region, including tuberculosis, pneumonia and sepsis. Meanwhile, antiviral treatment for HIV increases the risk of obesity and insulin resistance. Five-year mortality proportions of patients with diabetes varied from 4-57%. Screening studies identified high proportions (> 40%) with previously undiagnosed diabetes, and low levels of adequate glucose control among previously diagnosed diabetics. Barriers to accessing diagnosis and treatment included a lack of diagnostic tools and glucose monitoring equipment and high cost of diabetes treatment. The total annual cost of diabetes in the region was estimated at US$67.03 billion, or US$8836 per diabetic patient.

Conclusion

Diabetes exerts a significant burden in the region, and this is expected to increase. Many diabetic patients face significant challenges accessing diagnosis and treatment, which contributes to the high mortality and prevalence of complications observed. The significant interactions between diabetes and important infectious diseases highlight the need and opportunity for health planners to develop integrated responses to communicable and non-communicable diseases.

Diabetes in Sub Saharan Africa 1999-2011: epidemiology and public health implications. A systematic review

BACKGROUND

Diabetes prevalence is increasing globally, and Sub-Saharan Africa is no exception. With diverse health challenges, health authorities in Sub-Saharan Africa and international donors need robust data on the epidemiology and impact of diabetes in order to plan and prioritise their health programmes. This paper aims to provide a comprehensive and up-to-date review of the epidemiological trends and public health implications of diabetes in Sub-Saharan Africa.

METHODS

We conducted a systematic literature review of papers published on diabetes in Sub-Saharan Africa 1999-March 2011, providing data on diabetes prevalence, outcomes (chronic complications, infections, and mortality), access to diagnosis and care and economic impact.

RESULTS

Type 2 diabetes accounts for well over 90% of diabetes in Sub-Saharan Africa, and population prevalence proportions ranged from 1% in rural Uganda to 12% in urban Kenya. Reported type 1 diabetes prevalence was low and ranged from 4 per 100,000 in Mozambique to 12 per 100,000 in Zambia. Gestational diabetes prevalence varied from 0% in Tanzania to 9% in Ethiopia. Proportions of patients with diabetic complications ranged from 7-63% for retinopathy, 27-66% for neuropathy, and 10-83% for microalbuminuria. Diabetes is likely to increase the risk of several important infections in the region, including tuberculosis, pneumonia and sepsis. Meanwhile, antiviral treatment for HIV increases the risk of obesity and insulin resistance. Five-year mortality proportions of patients with diabetes varied from 4-57%. Screening studies identified high proportions (> 40%) with previously undiagnosed diabetes, and low levels of adequate glucose control among previously diagnosed diabetics. Barriers to accessing diagnosis and treatment included a lack of diagnostic tools and glucose monitoring equipment and high cost of diabetes treatment. The total annual cost of diabetes in the region was estimated at US$67.03 billion, or US$8836 per diabetic patient.

CONCLUSION

Diabetes exerts a significant burden in the region, and this is expected to increase. Many diabetic patients face significant challenges accessing diagnosis and treatment, which contributes to the high mortality and prevalence of complications observed. The significant interactions between diabetes and important infectious diseases highlight the need and opportunity for health planners to develop integrated responses to communicable and non-communicable diseases.

The impact of diabetes on tuberculosis treatment outcomes: a systematic review

BACKGROUND

Multiple studies of tuberculosis treatment have indicated that patients with diabetes mellitus may experience poor outcomes.We performed a systematic review and meta-analysis to quantitatively summarize evidence for the impact of diabetes on tuberculosis outcomes.

METHODS

We searched PubMed, EMBASE and the World Health Organization Regional Indexes from 1 January 1980 to 31 December 2010 and references of relevant articles for reports of observational studies that included people with diabetes treated for tuberculosis. We reviewed the full text of 742 papers and included 33 studies of which 9 reported culture conversion at two to three months, 12 reported the combined outcome of failure and death, 23 reported death, 4 reported death adjusted for age and other potential confounding factors, 5 reported relapse, and 4 reported drug resistant recurrent tuberculosis.

RESULTS

Diabetes is associated with an increased risk of failure and death during tuberculosis treatment. Patients with diabetes have a risk ratio (RR) for the combined outcome of failure and death of 1.69 (95% CI, 1.36 to 2.12). The RR of death during tuberculosis treatment among the 23 unadjusted studies is 1.89 (95% CI, 1.52 to 2.36), and this increased to an effect estimate of 4.95 (95% CI, 2.69 to 9.10) among the 4 studies that adjusted for age and other potential confounding factors. Diabetes is also associated with an increased risk of relapse (RR, 3.89; 95% CI, 2.43 to 6.23). We did not find evidence for an increased risk of tuberculosis recurrence with drug resistant strains among people with diabetes. The studies assessing sputum culture conversion after two to three months of tuberculosis therapy were heterogeneous with relative risks that ranged from 0.79 to 3.25.

CONCLUSIONS

Diabetes increases the risk of failure and death combined, death, and relapse among patients with tuberculosis. This study highlights a need for increased attention to treatment of tuberculosis in people with diabetes, which may include testing for suspected diabetes, improved glucose control, and increased clinical and therapeutic monitoring.

Cross-sectional assessment reveals high diabetes prevalence among newly-diagnosed tuberculosis cases

OBJECTIVE

To estimate the contribution of clinically-confirmed diabetes mellitus to tuberculosis (TB) rates in communities where both diseases are prevalent as a way to identify opportunities for TB prevention among diabetic patients.

METHODS

This is a prospective study in which TB patients ≥ 20 years old at TB clinics in the Texas-Mexico border were tested for diabetes. The risk of tuberculosis attributable to diabetes was estimated from statistics for the corresponding adult population.

FINDINGS

The prevalence of diabetes among TB patients was 39% in Texas and 36% in Mexico. Diabetes contributed 25% of the TB cases studied, whereas human immunodeficiency virus (HIV) infection contributed 5% or fewer. Among TB patients, fewer Mexicans than Texans were aware that they had diabetes before this study (4% and 19%, respectively). Men were also less frequently aware than women that they had diabetes (P = 0.03). Patients who knew that they had diabetes before the study had an 8-year history of the disease, on average, before being diagnosed with TB.

CONCLUSION

Patients with diabetes are at higher risk of contracting TB than non-diabetic patients. Integrating TB and diabetes control programmes worldwide would facilitate TB prevention among diabetes patients and increase the number of diabetics who learn of their condition, particularly among males. Such a strategy would lead to earlier case detection and improve the management of both TB and diabetes.

Tuberculosis in the global aging population

Despite the decline in the overall incidence of tuberculosis (TB) in many developed countries, it remains an important problem among the older population. The control of TB in the elderly remains a major challenge because of the limitations of the existing tools for the diagnosis and treatment of latent TB infection and clinically active disease. This article examines the current and possible future status of TB in the elderly, focusing on epidemiology, risk factors, preventive treatment strategies, and clinical disease.

Bi-directional screening for tuberculosis and diabetes: a systematic review

OBJECTIVE

To assess the yield of finding additional TB or diabetes mellitus (DM) cases through systematic screening and to determine the effectiveness of preventive TB therapy in people with DM.

METHODS

We systematically reviewed studies that had screened for active TB or implemented preventive therapy for TB among people with DM, and those that screened for DM among patients with TB. We searched published literature through PubMed and EMBASE and included studies that reported the number of TB cases identified among people with DM; the number of DM cases identified among patients with TB, or the relative incidence of TB between people with DM who received a TB prophylaxis and those who did not. We assessed the yield of screening by estimating the prevalence of TB or DM in each study, the prevalence ratio and difference where comparison populations were available, and the number of persons to screen to detect an additional case of TB or DM.

RESULTS

Twelve studies on screening for TB in people with DM and 18 studies on screening for DM in patients with TB met our inclusion criteria. Screening for TB in persons with DM demonstrated that TB prevalence in this population is high, ranging from 1.7% to 36%, and increasing with rising TB prevalence in the underlying population as well as with DM severity. Screening patients with TB for DM also yielded high prevalences of DM ranging from 1.9% to 35%. Two studies examining the role of TB preventive therapy in people with DM did not provide sufficient details for clear evidence of the effectiveness.

CONCLUSION

Active screening leads to the detection of more TB and DM with varying yield. This review highlights the need for further research in screening and preventive therapy.

Tuberculosis and diabetes mellitus: convergence of two epidemics

The link between diabetes mellitus and tuberculosis has been recognised for centuries. In recent decades, tuberculosis incidence has declined in high-income countries, but incidence remains high in countries that have high rates of infection with HIV, high prevalence of malnutrition and crowded living conditions, or poor tuberculosis control infrastructure. At the same time, diabetes mellitus prevalence is soaring globally, fuelled by obesity. There is growing evidence that diabetes mellitus is an important risk factor for tuberculosis and might affect disease presentation and treatment response. Furthermore, tuberculosis might induce glucose intolerance and worsen glycaemic control in people with diabetes. We review the epidemiology of the tuberculosis and diabetes epidemics, and provide a synopsis of the evidence for the role of diabetes mellitus in susceptibility to, clinical presentation of, and response to treatment for tuberculosis. In addition, we review potential mechanisms by which diabetes mellitus can cause tuberculosis, the effects of tuberculosis on diabetic control, and pharmacokinetic issues related to the co-management of diabetes and tuberculosis.

A review of co-morbidity between infectious and chronic disease in Sub Saharan Africa: TB and diabetes mellitus, HIV and metabolic syndrome, and the impact of globalization

Background

Africa is facing a rapidly growing chronic non-communicable disease burden whilst at the same time experiencing continual high rates of infectious disease. It is well known that some infections increase the risk of certain chronic diseases and the converse. With an increasing dual burden of disease in Sub Saharan Africa the associations between diseases and our understanding of them will become of increased public health importance.

Aims

In this review we explore the relationships reported between tuberculosis and diabetes mellitus, human immunodeficiency virus, its treatment and metabolic risk. We aimed to address the important issues surrounding these associations within a Sub Saharan African setting and to describe the impact of globalization upon them.

Findings

Diabetes has been associated with a 3-fold incident risk of tuberculosis and it is hypothesised that tuberculosis may also increase the risk of developing diabetes. During co-morbid presentation of tuberculosis and diabetes both tuberculosis and diabetes outcomes are reported to worsen. Antiretroviral therapy for HIV has been associated with an increased risk of developing metabolic syndrome and HIV has been linked with an increased risk of developing both diabetes and cardiovascular disease. Globalization is clearly related to an increased risk of diabetes and cardiovascular disease. It may be exerting other negative and positive impacts upon infectious and chronic non-communicable disease associations but at present reporting upon these is sparse.

Conclusion

The impact of these co-morbidities in Sub Saharan Africa is likely to be large. An increasing prevalence of diabetes may hinder efforts at tuberculosis control, increasing the number of susceptible individuals in populations where tuberculosis is endemic, and making successful treatment harder. Roll out of anti-retroviral treatment coverage within Sub Saharan Africa is an essential response to the HIV epidemic however it is likely to lead to a growing number of individuals suffering adverse metabolic consequences. One of the impacts of globalization is to create environments that increase both diabetes and cardiovascular risk but further work is needed to elucidate other potential impacts. Research is also needed to develop effective approaches to reducing the frequency and health impact of the co-morbidities described here.

Tuberculosis in poorly controlled type 2 diabetes: altered cytokine expression in peripheral white blood cells

BACKGROUND

Although the biological basis for the increased susceptibility of diabetic patients to tuberculosis remains unclear, the world is undergoing a type 2 diabetes pandemic. We hypothesize that chronic hyperglycemia leads to immunocompromise that facilitates progression to active tuberculosis. To assess this possibility, we determined whether patients with tuberculosis and diabetes (particularly those with chronic hyperglycemia), compared with patients with tuberculosis who did not have diabetes, presented altered cytokine responses to a mycobacterial antigen.

METHODS

Samples of whole blood from patients with tuberculosis and diabetes and from patients with tuberculosis who did not have diabetes was stimulated in vitro with purified protein derivative from Mycobacterium tuberculosis. We then determined whether there was an association between the levels of innate and adaptive cytokines secreted in response to the antigen and diabetes status, or diabetes with chronic hyperglycemia (measured by glycosylated hemoglobin level), after controlling for possible confounders.

RESULTS

Innate and type 1 cytokine responses were significantly higher in patients with tuberculosis who had diabetes than in nondiabetic control subjects. The effect was consistently and significantly more marked in diabetic patients with chronic hyperglycemia.

CONCLUSIONS

These data provide preliminary evidence that type 2 diabetes, especially type 2 diabetes involving chronic hyperglycemia, is associated with an altered immune response to M. tuberculosis. More-detailed knowledge of the underlying mechanisms should focus on the effect of chronic hyperglycemia on the immune response to help in understanding the enhanced susceptibility of diabetic patients to tuberculosis.

[Pulmonary tuberculosis and diabetes. A retrospective study of 60 patients in Tunisia]

BACKGROUND

Tuberculosis is a frequent infectious disease in Tunisia. The estimated case rate is 22.3 per 100,000 inhabitants. The risk of tuberculosis is 2 to 6 times greater in patients with diabetes. The purpose of this study was to analyze the particularities in the etiology, diagnosis and bacteriologic course of pulmonary tuberculosis in patients with diabetes and to evaluate the impact of tuberculosis on diabetes control.

METHOD

This retrospective case-control study of 142 patients with confirmed pulmonary tuberculosis seen from 2000-2006 compared the 60 patients with diabetes with the 82 without diabetes.

RESULTS

Diabetes was more frequent in older patients with tuberculosis and in women. 91.5% had type 2 diabetes. A history of contact with people with tuberculosis was significantly less frequent in the group with diabetes (13.3% vs 30.5%; p=0.01). Tuberculosis symptoms and their duration did not differ between the 2 groups. Basal lesions and cavitation occurred more frequently in the patients with diabetes, but this difference was not significant. The time for conversion to negative of sputum culture was longer in case patients (43+/-27 days) than in controls (28.2+/-20.5) (p=0.03). The proportion of patients with uncontrolled diabetes was elevated, and 50% required frequent insulin treatment.

CONCLUSION

Tuberculosis is frequently associated with diabetes, usually due to reactivation of Mycobacterium tuberculosis. It is characterized by a longer time to culture conversion to negative and a risk of uncontrolled diabetes that requires frequent treatment adjustment and insulin use.

Diabetes mellitus increases the risk of active tuberculosis: a systematic review of 13 observational studies

BACKGROUND

Several studies have suggested that diabetes mellitus (DM) increases the risk of active tuberculosis (TB). The rising prevalence of DM in TB-endemic areas may adversely affect TB control. We conducted a systematic review and a meta-analysis of observational studies assessing the association of DM and TB in order to summarize the existing evidence and to assess methodological quality of the studies.

METHODS AND FINDINGS

We searched the PubMed and EMBASE databases to identify observational studies that had reported an age-adjusted quantitative estimate of the association between DM and active TB disease. The search yielded 13 observational studies (n = 1,786,212 participants) with 17,698 TB cases. Random effects meta-analysis of cohort studies showed that DM was associated with an increased risk of TB (relative risk = 3.11, 95% CI 2.27-4.26). Case-control studies were heterogeneous and odds ratios ranged from 1.16 to 7.83. Subgroup analyses showed that effect estimates were higher in non-North American studies.

CONCLUSION

DM was associated with an increased risk of TB regardless of study design and population. People with DM may be important targets for interventions such as active case finding and treatment of latent TB and efforts to diagnose, detect, and treat DM may have a beneficial impact on TB control.

Impact of type 2 diabetes on manifestations and treatment outcome of pulmonary tuberculosis

Diabetes mellitus (DM) is a known risk factor for pulmonary tuberculosis (PTB). This study aimed to determine if type 2 DM alters manifestations and treatment outcome of PTB. Records of 217 consecutive culture-proven PTB patients were analysed retrospectively. The manifestations and treatment outcomes of 74 patients with type 2 DM (PTB-DM group) were compared to 143 patients without DM (PTB group). PTB-DM patients showed higher frequencies of fever, haemoptysis, positive acid-fast bacilli sputum smears, and consolidation, cavity, and lower lung field lesions on chest radiographs, and higher mortality rate. Furthermore, type 2 DM, age 65 years, and extensive radiographic disease were factors independently associated with an unfavorable outcome. This study confirmed that clinical manifestations and chest radiographs of PTB patients associated with type 2 DM significantly depart from the typical presentation. Type 2 DM seems to have a negative effect on treatment outcome of PTB.

A novel identification scheme for genus Mycobacterium, M. tuberculosis complex, and seven mycobacteria species of human clinical impact

Recently, the incidence of human mycobacterial infections due to species other than M. tuberculosis has increased worldwide. Since disease control depends on appropriate antimicrobial therapy, the precise identification of these species of clinical importance has become a major public health concern. Identification of mycobacteria has been hampered because of the lack of specific, rapid, and inexpensive methods. Therefore, we aimed at designing and validating a bacterial lysate-based polymerase chain reaction identification scheme. This scheme can classify clinical isolates into: (1) the genus Mycobacterium, (2) the M. tuberculosis complex, (3) the nontuberculous mycobacteria, and (4) the species M. avium, M. intracellulare, M. abscessus, M. chelonae, M. fortuitum and M. bovis of clinical importance, and M. gordonae, the most commonly encountered nonpathogenic species in clinical laboratories. By using M. fortuitum and M. avium lysates as models, the method sensitivity was determined to be 372 pg of DNA. In a blind parallel comparison between our approach and conventional biochemical tests, both assays correctly categorized 75 patient's mycobacterial isolates. However, our approach only required 4-9 h for categorization compared with at least 15 days by conventional tests. Furthermore, our methodology could also detect M. fortuitum and M. avium from liquid cultures, after only 2 and 6 days, respectively, of incubation. Our new identification scheme is therefore sensitive, specific, rapid, and economic. Additionally, it can help to provide proper treatment to patients, to control these diseases, and to improve our knowledge of the epidemiology of mycobacteriosis, all urgently needed, particularly in developing countries.

Type 2 diabetes and multidrug-resistant tuberculosis

The association between tuberculosis (TB) and diabetes is re-emerging with the epidemic of type 2 diabetes (T2DM). We analyzed retrospective data from 2878 TB patients across the Texas/Mexico border. Overall, 161/2878 (5.6%) patients had MDR TB (resistance to rifampin and isoniazid): Texas 49/1442 (3.4%) and Mexico 112/1436 (7.8%). In Texas, MDR TB was significantly associated with T2DM (OR 2.1, 95% CI 1.1-4.2) when adjusted for age, gender, drug and alcohol abuse, HIV infection and history of previous episode of TB; and in Mexico (OR 1.80, 95% CI 1.1-2.9) when adjusted for age and gender. Patients with T2DM in both countries were more likely to be compliant with DOTS therapy (Texas: OR 2.4, 95% CI 1.1-5.4) than patients without T2DM. In Texas, all but 3 of the T2DM patients with MDR TB were resistant at their first culture at the time of diagnosis. It is possible that impaired immunity in T2DM increases susceptibility to infection with resistant strains.

The role of interferon-gamma in the increased tuberculosis risk in type 2 diabetes mellitus

As patients with diabetes mellitus are at increased risk of developing tuberculosis, we hypothesized that this susceptibility to mycobacterial infection is due to a defective Th1-cytokine response. To explore this hypothesis, we examined four groups of subjects in Indonesia: 23 patients with tuberculosis, 34 patients with tuberculosis and diabetes, 32 patients with diabetes only and 36 healthy controls. Ex-vivo production of interferon (IFN)gamma, tumour necrosis factor-alpha and interleukin (IL)-1beta, 6, 10, -12 and -4 was measured following stimulation with Mycobacterium tuberculosis, Escherichia coli lipopolysaccharide and phytohaemagglutinin. Patients with active tuberculosis were found to have lower IFNgamma levels and a higher production of other pro-inflammatory cytokines and IL-4, both in the presence and absence of diabetes. Diabetes patients without tuberculosis, however, showed strongly reduced non-specific IFNgamma production, which is essential for inhibition of the initial growth of M. tuberculosis. Our data suggest that a defective non-specific immune response in diabetes may contribute to an increased susceptibility to develop tuberculosis.

Diabetes and tuberculosis: the impact of the diabetes epidemic on tuberculosis incidence

Background

Tuberculosis (TB) remains a major cause of mortality in developing countries, and in these countries diabetes prevalence is increasing rapidly. Diabetes increases the risk of TB. Our aim was to assess the potential impact of diabetes as a risk factor for incident pulmonary tuberculosis, using India as an example.

Methods

We constructed an epidemiological model using data on tuberculosis incidence, diabetes prevalence, population structure, and relative risk of tuberculosis associated with diabetes. We evaluated the contribution made by diabetes to both tuberculosis incidence, and to the difference between tuberculosis incidence in urban and rural areas.

Results

In India in 2000 there were an estimated 20.7 million adults with diabetes, and 900,000 incident adult cases of pulmonary tuberculosis. Our calculations suggest that diabetes accounts for 14.8% (uncertainty range 7.1% to 23.8%) of pulmonary tuberculosis and 20.2% (8.3% to 41.9%) of smear-positive (i.e. infectious) tuberculosis.

We estimate that the increased diabetes prevalence in urban areas is associated with a 15.2% greater smear-positive tuberculosis incidence in urban than rural areas – over a fifth of the estimated total difference.

Conclusion

Diabetes makes a substantial contribution to the burden of incident tuberculosis in India, and the association is particularly strong for the infectious form of tuberculosis. The current diabetes epidemic may lead to a resurgence of tuberculosis in endemic regions, especially in urban areas. This potentially carries a risk of global spread with serious implications for tuberculosis control and the achievement of the United Nations Millennium Development Goals.

Infections in Diabetes Mellitus and Hyperglycemia

Infections in diabetes mellitus are relatively more common and serious. Diabetic patients run the risk of acute metabolic decompensation during infections, and conversely patients with metabolic decompensation are at higher risk of certain invasive infections. Tight glycemic control is of paramount importance during acute infected or high stress state. Infections in diabetic patients result in extended hospital stays and additional financial burden. Given the risks of not alleviating the metabolic dysregulation and the benefits of decent glycemic control, it is necessary that besides antimicrobial therapy, equal emphasis be placed on intensified glycemic control.

Diabetes and the risk of tuberculosis: a neglected threat to public health?

OBJECTIVES

Tuberculosis (TB) remains a major global public health problem. In the past, a relationship between TB and diabetes mellitus (DM) was recognized, and its importance was acknowledged through joint treatment clinics. However, this is rarely highlighted in current research or control priorities. This paper aims to evaluate the evidence for an association between these two diseases.

METHODS

A Medline literature search was undertaken, supplemented by checking references and contacting experts. We critically appraised studies that quantified the association between TB and DM, and were published after 1995. We assessed study quality according to criteria such as sample size, method of selection of cases and controls, losses to follow-up, quality and method of control of confounding, and summarized the results narratively and in tabular form.

RESULTS

All studies identified statistically significant and clinically important associations, with the increase in risk or odds of TB varying between 1.5- and 7.8-fold for those with DM. Risk was highest at younger ages. Most studies had not measured and controlled adequately for potential major confounders.

DISCUSSION

There is strong evidence for an association between TB and DM, which has potential public health implications. Further well-designed studies are needed to assess the magnitude precisely.

The effect of type 2 diabetes mellitus on the presentation and treatment response of pulmonary tuberculosis

BACKGROUND

Diabetes mellitus (DM) is a known risk factor for tuberculosis (TB), and with the increasing prevalence of type 2 DM in less developed regions, many patients with TB will have concomitant DM. Presently, little is known about the effect of DM on the clinical presentation and treatment outcome of TB.

METHODS

In an urban setting in Indonesia, 737 patients with pulmonary TB were screened for DM and were followed up prospectively during TB treatment. Clinical characteristics and outcome were compared between patients with TB who had DM and patients with TB who did not have DM.

RESULTS

DM was diagnosed in 14.8% of patients with TB and was associated with older age and a greater body weight. On presentation, diabetic patients with TB had more symptoms but had no evidence of more-severe TB. After 2 months, results of sputum microscopic examination was more often positive in diabetic patients (18.1% vs. 10.0%). After 6 months, 22.2% of cultured sputum specimens from diabetic patients were positive for Mycobacterium tuberculosis (adjusted odds ratio, 7.65; P=.004).

CONCLUSION

DM seems to have a negative effect on the outcome of TB treatment. The underlying mechanisms for the different response to treatment in diabetic patients with TB must be explored. Screening for DM and subsequent glycemic control may improve the outcome of TB treatment.

Tuberculosis susceptibility of diabetic mice

Increased susceptibility to infections, including tuberculosis (TB), is a major cause of morbidity and mortality in patients with diabetes. Despite the clinical importance of this problem, little is known about how diabetes impairs protective immunity. We modeled this phenomenon by infecting acute (< or = 1 mo) or chronic (> or = 3 mo) diabetic mice with a low aerosol dose of Mycobacterium tuberculosis (Mtb) Erdman. Diabetes was induced by streptozotocin (STZ) treatment of C57BL/6 mice, while another mouse strain and diabetes model were used to confirm key observations. Lungs from acute diabetic and euglycemic mice had similar bacterial burdens, cytokine expression profiles, and histopathology. In contrast, chronic diabetic mice had > 1 log higher bacterial burden and more inflammation in the lung compared with euglycemic mice. The expression of adaptive immunity was delayed in chronic diabetic mice, shown by reduced early production of IFN-gamma in the lung and by the presence of fewer Mtb antigen (ESAT-6)-responsive T cells compared with euglycemic mice within the first month of infection. However, after 2 months of TB disease proinflammatory cytokines levels were higher in chronic diabetic than euglycemic mice. Here we show that Mtb infection of STZ-treated mice provides a useful model to study the effects of hyperglycemia on immunity. Our data indicate that the initiation of adaptive immunity is impaired by chronic hyperglycemia, resulting in a higher steady-state burden of Mtb in the lung.

Type 2 diabetes and tuberculosis in a dynamic bi-national border population

The epidemic of type 2 diabetes in the United States prompted us to explore the association between diabetes and tuberculosis (TB) on the South Texas-Mexico border, in a large population of mostly non-hospitalized TB patients. We examined 6 years of retrospective data from all TB patients (n=5049) in South Texas and northeastern Mexico and found diabetes self-reported by 27.8% of Texan and 17.8% of Mexican TB patients, significantly exceeding national self-reported diabetes rates for both countries. Diabetes comorbidity substantially exceeded that of HIV/AIDS. Patients with TB and diabetes were older, more likely to have haemoptysis, pulmonary cavitations, be smear positive at diagnosis, and remain positive at the end of the first (Texas) or second (Mexico) month of treatment. The impact of type 2 diabetes on TB is underappreciated, and in the light of its epidemic status in many countries, it should be actively considered by TB control programmes, particularly in older patients.

Gender differentials of pulmonary tuberculosis transmission and reactivation in an endemic area

BACKGROUND

In most low income countries there are twice as many cases of tuberculosis (TB) reported among men than among women, a difference commonly attributed to biological and epidemiological characteristics as well as socioeconomic and cultural barriers in access to health care. The World Health Organization has encouraged gender specific comparisons in TB rates to determine whether women with TB are less likely than men with TB to be diagnosed, reported, and treated. A study was undertaken to identify gender based differences in patients with pulmonary TB and to use this information to improve TB control efforts.

METHODS

Individuals with a cough for more than 2 weeks in southern Mexico were screened from March 1995 to April 2003. Clinical and mycobacteriological information (isolation, identification, drug susceptibility testing and IS6110 based genotyping, and spoligotyping) was collected from those with bacteriologically confirmed pulmonary TB. Patients were treated in accordance with official norms and followed to ascertain treatment outcome, retreatment, and vital status.

RESULTS

623 patients with pulmonary TB were enrolled. The male:female incidence rate ratio for overall, reactivated, and recently transmitted disease was 1.58 (95% CI 1.34 to 1.86), 1.64 (95% CI 1.36 to 1.98), and 1.41 (95% CI 1.01 to 1.96), respectively. Men were more likely than women to default from treatment (adjusted OR 3.30, 95% CI 1.46 to 7.43), to be retreated (hazard ratio (HR) 3.15, 95% CI 1.38 to 7.22), and to die from TB (HR 2.23, 95% CI 1.25 to 3.99).

CONCLUSIONS

Higher rates of transmitted and reactivated disease and poorer treatment outcomes among men are indicators of gender differentials in the diagnosis and treatment of pulmonary TB, and suggest specific strategies in endemic settings.

Epidemiology of type 2 diabetes in Mexico

The epidemiology of diabetes in Mexico is reviewed. In less than four decades, diabetes has become the main health problem in Mexico. It is the principal cause of death in women and the second among men since the year 2000. It is the primary cause of premature retirement, blindness, and kidney failure. By the year 2025, close to 11.7 million Mexicans are expected to be diagnosed with diabetes. In the year 2000, diabetes was the 11th most frequent cause of hospitalization but the second most common cause of hospital mortality. The number of cases reported in children has also increased since 1995. The results of population-based, nationwide surveys have detected a 25% increment over a 7-year period. Fourteen percent of people with diabetes are <40 years of age, and a large proportion of patients have other conditions that determine the appearance of macrovascular complications and kidney failure. In addition, many cases do not reach treatment goals. In conclusion, the growing number of cases and the significant health burden imposed on affected subjects makes diabetes a disease that needs to be prevented. Well-planned strategies are urgently needed to modify the lifestyle of the population and to increase their physical activity. In addition, an enormous effort will be required to educate the population and physicians to improve the diagnosis and treatment of patients with diabetes.