Statin use and risk of tuberculosis: a systemic review of observational studies

Interaction of Glycemic Control and Statin Use on Diabetes-Tuberculosis Treatment Outcome: A Nested Case-Control Study

This study aims to explore the interaction of glycemic control and statin use on the treatment outcomes of pulmonary tuberculosis-diabetes comorbidity (PTB-DM) patients. A nested case-control study was conducted in a tuberculosis patients' cohort. We defined cases as patients who experienced unfavorable outcomes. Glycemic control was estimated at the baseline. Statin use was obtained from medical records. The multivariate logistic regression models were developed, and the interaction table invented by Andersson was adopted to analyze the interaction of glycemic control and statin use on treatment outcomes. A total of 2,047 patients were included in this study. There was a significant interaction between glycemic control and statin use on the treatment outcomes. Patients with good glycemic control and no statin use (OR = 0.464, 95% CI: 0.360-0.623) had a lower risk of unfavorable outcomes than those with poor glycemic control and statin use (OR = 0.604, 95% CI: 0.401-0.734). Patients with good glycemic control and statin use had the lowest risk of unfavorable outcomes (OR = 0.394, 95% CI: 0.264-0.521). Glycemic control in diabetes-tuberculosis treatment should be paid considerable attention. Patients can benefit from statin use even if they have poor glycemic control. Patients with good glycemic control and statin use can have the best outcomes.

Potential of Neuroinflammation-Modulating Strategies in Tuberculous Meningitis: Targeting Microglia

Tuberculous meningitis (TBM) is the most severe complication of tuberculosis (TB) and is associated with high rates of disability and mortality. Mycobacterium tuberculosis (M. tb), the infectious agent of TB, disseminates from the respiratory epithelium, breaks through the blood-brain barrier, and establishes a primary infection in the meninges. Microglia are the core of the immune network in the central nervous system (CNS) and interact with glial cells and neurons to fight against harmful pathogens and maintain homeostasis in the brain through pleiotropic functions. However, M. tb directly infects microglia and resides in them as the primary host for bacillus infections. Largely, microglial activation slows disease progression. The non-productive inflammatory response that initiates the secretion of pro-inflammatory cytokines and chemokines may be neurotoxic and aggravate tissue injuries based on damages caused by M. tb. Host-directed therapy (HDT) is an emerging strategy for modulating host immune responses against diverse diseases. Recent studies have shown that HDT can control neuroinflammation in TBM and act as an adjunct therapy to antibiotic treatment. In this review, we discuss the diverse roles of microglia in TBM and potential host-directed TB therapies that target microglia to treat TBM. We also discuss the limitations of applying each HDT and suggest a course of action for the near future.

Fluvastatin Converts Human Macrophages into Foam Cells with Increased Inflammatory Response to Inactivated Mycobacterium tuberculosis H37Ra

Cholesterol biosynthesis inhibitors (statins) protect hypercholesterolemic patients against developing active tuberculosis, suggesting that these drugs could help the host to control the pathogen at the initial stages of the disease. This work studies the effect of fluvastatin on the early response of healthy peripheral blood mononuclear cells (PBMCs) to inactivated Mycobacterium tuberculosis (Mtb) H37Ra. We found that in fluvastatin-treated PBMCs, most monocytes/macrophages became foamy cells that overproduced NLRP3 inflammasome components in the absence of immune stimulation, evidencing important cholesterol metabolism/immunity connections. When both fluvastatin-treated and untreated PBMCs were exposed to Mtb H37Ra, a small subset of macrophages captured large amounts of bacilli and died, concentrating the bacteria in necrotic areas. In fluvastatin-untreated cultures, most of the remaining macrophages became epithelioid cells that isolated these areas of cell death in granulomatous structures that barely produced IFNγ. By contrast, in fluvastatin-treated cultures, foamy macrophages surrounded the accumulated bacteria, degraded them, markedly activated caspase-1 and elicited a potent IFNγ/cytotoxic response. In rabbits immunized with the same bacteria, fluvastatin increased the tuberculin test response. We conclude that statins may enhance macrophage efficacy to control Mtb, with the help of adaptive immunity, offering a promising tool in the design of alternative therapies to fight tuberculosis.

Association between biomarkers of inflammation and dyslipidemia in drug resistant tuberculosis in Uganda

BACKGROUND

Active tuberculosis (TB) significantly increases the risk of cardiovascular disease, but the underlying mechanisms remain unclear. This study aimed to investigate the association between inflammation biomarkers and dyslipidemia in patients with drug-resistant TB (DR-TB).

METHODS

This was a secondary analysis of data from a cross-sectional multi-center study in Uganda conducted 2021. Participants underwent anthropometric measurements and laboratory tests included a lipid profile, full haemogram and serology for HIV infection. Dyslipidemia was defined as total cholesterol > 5.0 mmol/l and/or low-density lipoprotein cholesterol > 4.14 mmol/l, and/or triglycerides (TG) ≥ 1.7 mmol/l, and/or high density lipoprotein cholesterol (HDL-c) < 1.03 mmol/l for men and < 1.29 mmol/l for women. Biomarkers of inflammation were leukocyte, neutrophil, lymphocyte, monocyte, and platelet counts, as well as neutrophil/lymphocyte (NLR), platelet/lymphocyte, and lymphocyte/monocyte (LMR) ratios, mean corpuscular volume (MCV), and the systemic immune inflammation index (SII) (neutrophil × platelet/lymphocyte). Modified Poisson Regression analysis was used for determining the association of the biomarkers and dyslipidemia.

RESULTS

Of 171 participants, 118 (69.0%) were co-infected with HIV. The prevalence of dyslipidemia was 70.2% (120/171) with low HDL-c (40.4%, 69/171) and hypertriglyceridemia (22.5%, 38/169) being the most common components. Patients with dyslipidemia had significantly higher lymphocyte (P = 0.008), monocyte (P < 0.001), and platelet counts (P = 0.014) in addition to a lower MCV (P < 0.001) than those without dyslipidemia. Further, patients with dyslipidemia had lower leucocyte (P < 0.001) and neutrophil (P = 0.001) counts, NLR (P = 0.008), LMR (P = 0.006), and SII (P = 0.049). The MCV was inversely associated with low HDL-C (adjusted prevalence ratio (aPR) = 0.97, 95% CI 0.94-0.99, P = 0.023) but was positively associated with hypertriglyceridemia (aPR = 1.04, 95% CI 1.00-1.08, P = 0.052).

CONCLUSIONS

Individuals with dyslipidemia exhibited elevated lymphocyte, monocyte, and platelet counts compared to those without. However, only MCV demonstrated an independent association with specific components of dyslipidemia. There is need for further scientific inquiry into the potential impact of dyslipidemia on red cell morphology and a pro-thrombotic state among patients with TB.

Repositioning of HMG-CoA Reductase Inhibitors as Adjuvants in the Modulation of Efflux Pump-Mediated Bacterial and Tumor Resistance

Efflux pump (EP)-mediated multidrug resistance (MDR) seems ubiquitous in bacterial infections and neoplastic diseases. The diversity and lack of specificity of these efflux mechanisms raise a great obstacle in developing drugs that modulate efflux pumps. Since developing novel chemotherapeutic drugs requires large investments, drug repurposing offers a new approach that can provide alternatives as adjuvants in treating resistant microbial infections and progressive cancerous diseases. Hydroxy-methyl-glutaryl coenzyme-A (HMG-CoA) reductase inhibitors, also known as statins, are promising agents in this respect. Originally, statins were used in the therapy of dyslipidemia and for the prevention of cardiovascular diseases; however, extensive research has recently been performed to elucidate the functions of statins in bacterial infections and cancers. The mevalonate pathway is essential in the posttranslational modification of proteins related to vital eukaryotic cell functions. In this article, a comparative review is given about the possible role of HMG-CoA reductase inhibitors in managing diseases of bacterial and neoplastic origin. Molecular research and clinical studies have proven the justification of statins in this field. Further well-designed clinical trials are urged to clarify the significance of the contribution of statins to the lower risk of disease progression in bacterial infections and cancerous diseases.

Revolutionizing control strategies against Mycobacterium tuberculosis infection through selected targeting of lipid metabolism

Lipid species play a critical role in the growth and virulence expression of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). During Mtb infection, foamy macrophages accumulate lipids in granulomas, providing metabolic adaptation and survival strategies for Mtb against multiple stresses. Host-derived lipid species, including triacylglycerol and cholesterol, can also contribute to the development of drug-tolerant Mtb, leading to reduced efficacy of antibiotics targeting the bacterial cell wall or transcription. Transcriptional and metabolic analyses indicate that lipid metabolism-associated factors of Mtb are highly regulated by antibiotics and ultimately affect treatment outcomes. Despite the well-known association between major antibiotics and lipid metabolites in TB treatment, a comprehensive understanding of how altered lipid metabolites in both host and Mtb influence treatment outcomes in a drug-specific manner is necessary to overcome drug tolerance. The current review explores the controversies and correlations between lipids and drug efficacy in various Mtb infection models and proposes novel approaches to enhance the efficacy of anti-TB drugs. Moreover, the review provides insights into the efficacious control of Mtb infection by elucidating the impact of lipids on drug efficacy. This review aims to improve the effectiveness of current anti-TB drugs and facilitate the development of innovative therapeutic strategies against Mtb infection by making reverse use of Mtb-favoring lipid species.

Human alveolar macrophage metabolism is compromised during Mycobacterium tuberculosis infection

Pulmonary macrophages have two distinct ontogenies: long-lived embryonically-seeded alveolar macrophages (AM) and bone marrow-derived macrophages (BMDM). Here, we show that after infection with a virulent strain of Mycobacterium tuberculosis (H37Rv), primary murine AM exhibit a unique transcriptomic signature characterized by metabolic reprogramming distinct from conventional BMDM. In contrast to BMDM, AM failed to shift from oxidative phosphorylation (OXPHOS) to glycolysis and consequently were unable to control infection with an avirulent strain (H37Ra). Importantly, healthy human AM infected with H37Ra equally demonstrated diminished energetics, recapitulating our observation in the murine model system. However, the results from seahorse showed that the shift towards glycolysis in both AM and BMDM was inhibited by H37Rv. We further demonstrated that pharmacological (e.g. metformin or the iron chelator desferrioxamine) reprogramming of AM towards glycolysis reduced necrosis and enhanced AM capacity to control H37Rv growth. Together, our results indicate that the unique bioenergetics of AM renders these cells a perfect target for Mtb survival and that metabolic reprogramming may be a viable host targeted therapy against TB.

Cardiovascular Involvement in Tuberculosis: From Pathophysiology to Diagnosis and Complications-A Narrative Review

Although primarily a lung disease, extra-pulmonary tuberculosis (TB) can affect any organ or system. Of these, cardiovascular complications associated with disease or drug toxicity significantly worsen the prognosis. Approximately 60% of patients with TB have a cardiovascular disease, the most common associated pathological entities being pericarditis, myocarditis, and coronary artery disease. We searched the electronic databases PubMed, MEDLINE, and EMBASE for studies that evaluated the impact of TB on the cardiovascular system, from pathophysiological mechanisms to clinical and paraclinical diagnosis of cardiovascular involvement as well as the management of cardiotoxicity associated with antituberculosis medication. The occurrence of pericarditis in all its forms and the possibility of developing constrictive pericarditis, the association of concomitant myocarditis with severe systolic dysfunction and complication with acute heart failure phenomena, and the long-term development of aortic aneurysms with risk of complications, as well as drug-induced toxicity, pose complex additional problems in the management of patients with TB. In the era of multidisciplinarity and polymedication, evidence-based medicine provides various tools that facilitate an integrative management that allows early diagnosis and treatment of cardiac pathologies associated with TB.

Cardiovascular risk factors among people with drug-resistant tuberculosis in Uganda

Background

Tuberculosis (TB) and its risk factors are independently associated with cardiovascular disease (CVD). We determined the prevalence and associations of CVD risk factors among people with drug-resistant tuberculosis (DRTB) in Uganda.

Methods

In this cross-sectional study, we enrolled people with microbiologically confirmed DRTB at four treatment sites in Uganda between July to December 2021. The studied CVD risk factors were any history of cigarette smoking, diabetes mellitus (DM) hypertension, high body mass index (BMI), central obesity and dyslipidaemia. We used modified Poisson regression models with robust standard errors to determine factors independently associated with each of dyslipidaemia, hypertension, and central obesity.

Results

Among 212 participants, 118 (55.7%) had HIV. Overall, 196 (92.5%, 95% confidence interval (CI) 88.0-95.3) had ≥ 1 CVD risk factor. The prevalence; 95% CI of individual CVD risk factors was: dyslipidaemia (62.5%; 55.4–69.1), hypertension (40.6%; 33.8–47.9), central obesity (39.3%; 32.9–46.1), smoking (36.3%; 30.1–43.1), high BMI (8.0%; 5.0–12.8) and DM (6.5%; 3.7–11.1). Dyslipidaemia was associated with an increase in glycated haemoglobin (adjusted prevalence ratio (aPR) 1.14, 95%CI 1.06–1.22). Hypertension was associated with rural residence (aPR 1.89, 95% CI 1.14–3.14) and previous history of smoking (aPR 0.46, 95% CI 0.21–0.98). Central obesity was associated with increasing age (aPR 1.02, 95%CI 1.00–1.03), and elevated diastolic blood pressure (aPR 1.03 95%CI 1.00–1.06).

Conclusion

There is a high prevalence of CVD risk factors among people with DRTB in Uganda, of which dyslipidaemia is the commonest. We recommend integrated services for identification and management of CVD risk factors in DRTB.

Effect of Oral Antidiabetic Drugs on Tuberculosis Risk and Treatment Outcomes: Systematic Review and Meta-Analysis

Tuberculosis and diabetes mellitus are two global pandemics and rising public health problems. Recent studies suggest that oral antidiabetic drugs (OADs) could reduce the risk of tuberculosis and improve clinical outcomes. However, the evidence is controversial. Therefore, we aimed to assess the effect of OADs on the risk of tuberculosis and treatment outcomes. We systematically searched for six databases from inception to 31 August 2022. We followed a predefined PICO/PECO strategy and included two randomized controlled trials and sixteen observational studies. This study collects 1,109,660 participants, 908,211 diabetic patients, and at least 13,841 tuberculosis cases. Our results show that metformin decreases the risk of active tuberculosis by 40% (RR 0.60; 95% CI 0.47-0.77) in diabetic patients. In addition, metformin exhibits a dose-response gradient (medium doses reduce the risk of active tuberculosis by 45%, while high doses reduce this risk by 52%). On the other hand, DPP IV inhibitors increase the risk of active tuberculosis by 43% (RR 1.43; 95% CI 1.02-2.02). Subgroup analysis showed that study design and metformin dose accounted for the heterogeneity. We conclude that metformin significantly protects against active tuberculosis among diabetic patients. On the contrary, DPP IV inhibitors could increase the risk of developing active tuberculosis.

Further insights into to the role of statins against active tuberculosis: systematic review and meta-analysis

OBJECTIVES

Tuberculosis is a major cause of global morbidity and mortality. Statins could be associated with a lower risk of some infectious diseases, including tuberculosis. Statins could reduce the risk of latent tuberculosis infection and active tuberculosis, acting as an adjuvant in treating tuberculosis. This study aimed to determine if statins reduce the risk of active tuberculosis.

METHODS

We systematically analyzed 8 databases from inception to December 2021. We included articles without language restriction if they met our inclusion and exclusion criteria and the PECO strategy (Population: adults without active pulmonary tuberculosis; Exposure: treatment with any statin; Comparator: no use of statins; Outcome: active tuberculosis). Odds Ratios (ORs) with 95% confidence intervals (CIs) were pooled using random- effects models regardless of heterogeneity quantified by Cochran's Q and I² statistics. We performed subgroup analyses according to the participants' diabetic status and follow-up length (≤10 years or >10 years).

RESULTS

Twelve articles reporting observational studies involving 3.038.043 participants, including at least 32.668 cases of active tuberculosis. Eight reported retrospective cohort studies, three nested case-control study, and one was a case control study.According to our meta-analysis, statins may reduce the risk of active tuberculosis, in the general population (OR 0.66; 95% CI, 0.54-0.81), in non-diabetic (OR 0.66; 95% CI, 0.54-0.80) and in diabetic patients (OR 0.65; 95% CI, 0.49-0.87). This protective effect did not differ according to the participants' diabetic status nor follow-up length (test for subgroup differences I²=0). We found significant clinical and methodological heterogeneity. Similarly, the forest plot, and the I² and Chi² statistics suggested considerable statistical heterogeneity (I²=95%, p<0.05, respectively). Of the 12 included studies, 9 were at low risk of bias and 3 were at high risk of bias. Similarly, according to the funnel plot, it is very likely that there are important publication biases.

CONCLUSION

Statin use may significantly reduce the risk of tuberculosis in the general population, diabetic and non-diabetic patients. Nevertheless, caution should be exercised when interpreting these conclusions, due to the quality of the evidence, the heterogeneity of the studies, the presence of bias, and the difficulty in extrapolating these results to populations of other races and ethnicities.

Diabetes-Associated Susceptibility to Tuberculosis: Contribution of Hyperglycemia vs. Dyslipidemia

Diabetes is a major risk factor for tuberculosis (TB). Diabetes increases the risk of the progression from latent tuberculosis infection (LTBI) to active pulmonary TB and TB patients with diabetes are at greater risk of more severe disease and adverse TB treatment outcomes compared to TB patients without co-morbidities. Diabetes is a complex disease, characterised not only by hyperglycemia but also by various forms of dyslipidemia. However, the relative contribution of these underlying metabolic factors to increased susceptibility to TB are poorly understood. This review summarises our current knowledge on the epidemiology and clinical manifestation of TB and diabetes comorbidity. We subsequently dissect the relative contributions of body mass index, hyperglycemia, elevated cholesterol and triglycerides on TB disease severity and treatment outcomes. Lastly, we discuss the impact of selected glucose and cholesterol-lowering treatments frequently used in the management of diabetes on TB treatment outcomes.

Host Immune-Metabolic Adaptations Upon Mycobacterial Infections and Associated Co-Morbidities

Mycobacterial diseases are a major public health challenge. Their causative agents include, in order of impact, members of the Mycobacterium tuberculosis complex (causing tuberculosis), Mycobacterium leprae (causing leprosy), and non-tuberculous mycobacterial pathogens including Mycobacterium ulcerans. Macrophages are mycobacterial targets and they play an essential role in the host immune response to mycobacteria. This review aims to provide a comprehensive understanding of the immune-metabolic adaptations of the macrophage to mycobacterial infections. This metabolic rewiring involves changes in glycolysis and oxidative metabolism, as well as in the use of fatty acids and that of metals such as iron, zinc and copper. The macrophage metabolic adaptations result in changes in intracellular metabolites, which can post-translationally modify proteins including histones, with potential for shaping the epigenetic landscape. This review will also cover how critical tuberculosis co-morbidities such as smoking, diabetes and HIV infection shape host metabolic responses and impact disease outcome. Finally, we will explore how the immune-metabolic knowledge gained in the last decades can be harnessed towards the design of novel diagnostic and therapeutic tools, as well as vaccines.

Relationship between total cholesterol level and tuberculosis risk in a nationwide longitudinal cohort

The association between the total cholesterol level and tuberculosis (TB) risk has been controversial. Our study aimed to evaluate whether total cholesterol level can predict the risk of TB. Data from 5,000,566 subjects who participated in a health screening exam in 2009 were investigated using the Korean National Health Insurance Service database (2009–2018). Cox hazard regression analyses were used to evaluate TB risk according to the quartile of total cholesterol levels. During an average of 8.2 years of follow-up, 32,078 cases of TB occurred. There was a significant inverse association between the total cholesterol level and TB risk. Compared with subjects in the highest quartile, those in the lowest quartile had a 1.35-fold increased TB risk (95% confidence interval = 1.31–1.39). The association between total cholesterol level and TB risk was more apparent in young subjects (age < 65 years), those without diabetes mellitus (DM), and those without obesity (p for interaction < 0.001 for age group, DM, and body mass index). Although there was a significant inverse association between total cholesterol level and TB risk in subjects who did not use a statin, no significant association was observed between the total cholesterol level and TB risk in subjects who used a statin. A low total cholesterol level was significantly associated with an increased risk of TB, even after adjusting for confounders, especially in patients younger than 65 years, those without DM or obesity, and those who did not use a statin.

The association of atherosclerotic cardiovascular disease and statin use with inflammation and treatment outcomes in tuberculosis

Tuberculosis (TB) and atherosclerotic cardiovascular disease (ASCVD) have a close epidemiological and pathogenetic overlap. Thus, it becomes essential to understand the relationship between ASCVD and TB outcomes. From our retrospective cohort on drug-susceptible TB patients at the National Taiwan University Hospital, we assessed the association of pre-existing ASCVD (coronary artery disease (CAD) and atherothrombotic stroke (ATS)) with 9-month all-cause and infection-related mortality and the extent of mediation by systemic inflammatory markers. We determined the effect of pre-existing ASCVD on 2-month sputum microbiological status. Among ASCVD patients, we assessed the association of statin use on mortality. Nine-month all-cause mortality was higher in CAD patients with prior acute myocardial infarction (CAD⁺AMI⁺) (adjusted HR 2.01, 95%CI 1.38–3.00) and ATS patients (aHR 2.79, 95%CI 1.92–4.07) and similarly, for infection-related mortality was higher in CAD⁺AMI⁺ (aHR 1.95, 95%CI 1.17–3.24) and ATS (aHR 2.04, 95%CI 1.19–3.46) after adjusting for confounding factors. Pre-existing CAD (AMI^- or AMI⁺) or ATS did not change sputum culture conversion or sputum smear AFB positivity at 2 months. The CAD⁺AMI⁺ group had significantly higher levels of CRP at TB diagnosis in the multivariable linear regression analysis (Adjusted B(SE) 1.24(0.62)). CRP mediated 66% (P = 0.048) and 25% (P = 0.033) of the association all-cause mortality with CAD⁺AMI⁻ and CAD⁺AMI⁺, respectively. In summary, patients with ASCVD have higher hazards of 9-month all-cause and infection-related mortality, with elevated serum inflammation mediating one to three-quarters of this association when adjusted for confounders. Statin use was associated with lower all-cause mortality among patients with ASCVD.

Statin use for the prevention of seizure and epilepsy in the patients at risk: A systematic review and meta-analysis of cohort studies

OBJECTIVE

Statin use for the prevention of seizure and epilepsy had been suggested but remained controversial. We sought to search existing literature to determine whether prophylactic use of statin reduced the incidence of seizure and epilepsy in the patients at risk.

METHODS

Three electronic databases were thoroughly searched to identify clinical studies investigating the effects of statin use on patients at the risk of seizure or epilepsy. Regardless of heterogeneity quantified, a random effects meta-analyses were used to synthesize the evidence, to pool odds ratios (ORs) and corresponding 95 % confidence intervals (CIs).

RESULTS

Seven cohort studies involving 26,042 patients with newly-onset epileptogenic brain insults and no history of seizure and epilepsy before were included. Compared with patients didn't receive statin treatment after epileptogenic brain insults, those treated with statin had a lower risk of epilepsy (5 studies; 22,849 patients; pooled OR, 0.48; 95 % CI, 0.31 to 0.73; p =  0.001) and seizure (4 studies; 6076 subjects; pooled OR, 0.35; 95 % CI, 0.25 to 0.48; p =  0.001).

CONCLUSIONS

Evidence from this meta-analysis suggested that the use of statin should as primary prevention for patients with risk of seizures and epilepsy. Considering the limited number and quality of available studies, future randomized controlled trials are required to further demonstrate the association between statin use and incident of seizure and epilepsy.