Fixed-dose combination associated with faster time to smear conversion compared to separate tablets of anti-tuberculosis drugs in patients with poorly controlled diabetes and pulmonary tuberculosis in Qatar

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.

Rodent-Related Zoonotic Pathogens at the Human-Animal-Environment Interface in Qatar: A Systematic Review and Meta-Analysis

Rodents are one of the most diversified terrestrial mammals, and they perform several beneficial activities in nature. These animals are also important as carriers of many pathogens with public health importance. The current systematic review was conducted to formulate a true depiction of rodent-related zoonoses in Qatar. Following systematic searches on PubMed, Scopus, Science Direct, and Web of Science and a screening process, a total of 94 published articles were selected and studied. The studied articles reported 23 rodent-related zoonotic pathogens that include nine bacterial, eleven parasitic, and three viral pathogens, from which the frequently reported pathogens were Mycobacterium tuberculosis (32 reports), Escherichia coli (23), and Salmonella spp. (16). The possible pathway of entry of the rodent-borne pathogens can be the land port, seaports, and airport of Qatar through carrier humans and animals, contaminated food, and agricultural products. The pathogens can be conserved internally by rodents, pets, and livestock; by agricultural production systems; and by food marketing chains. The overall estimated pooled prevalence of the pathogens among the human population was 4.27% (95%CI: 4.03–4.51%; p < 0.001) with significant heterogeneity (I² = 99.50%). The top three highest prevalent pathogens were M.tuberculosis (30.90%; 22.75–39.04%; p < 0.001; I² = 99.70%) followed by Toxoplasma gondii (21.93%; 6.23–37.61%; p < 0.001; I² = 99.30%) and hepatitis E virus (18.29%; 11.72–24.86%; p < 0.001; I² = 96.70%). However, there is a knowledge gap about the listed pathogens regarding the occurrence, transmission pathways, and rodent role in transmission dynamics at the human–animal–environment interface in Qatar. Further studies are required to explore the role of rodents in spreading zoonotic pathogens through the One Health framework, consisting of zoologists, ecologists, microbiologists, entomologists, veterinarians, and public health experts in this country.

Dynamics of sputum conversion during effective tuberculosis treatment: A systematic review and meta-analysis

BACKGROUND

Two weeks' isolation is widely recommended for people commencing treatment for pulmonary tuberculosis (TB). The evidence that this corresponds to clearance of potentially infectious tuberculous mycobacteria in sputum is not well established. This World Health Organization-commissioned review investigated sputum sterilisation dynamics during TB treatment.

METHODS AND FINDINGS

For the main analysis, 2 systematic literature searches of OvidSP MEDLINE, Embase, and Global Health, and EBSCO CINAHL Plus were conducted to identify studies with data on TB infectiousness (all studies to search date, 1 December 2017) and all randomised controlled trials (RCTs) for drug-susceptible TB (from 1 January 1990 to search date, 20 February 2018). Included articles reported on patients receiving effective treatment for culture-confirmed drug-susceptible pulmonary TB. The outcome of interest was sputum bacteriological conversion: the proportion of patients having converted by a defined time point or a summary measure of time to conversion, assessed by smear or culture. Any study design with 10 or more particpants was considered. Record sifting and data extraction were performed in duplicate. Random effects meta-analyses were performed. A narrative summary additionally describes the results of a systematic search for data evaluating infectiousness from humans to experimental animals (PubMed, all studies to 27 March 2018). Other evidence on duration of infectiousness-including studies reporting on cough dynamics, human tuberculin skin test conversion, or early bactericidal activity of TB treatments-was outside the scope of this review. The literature search was repeated on 22 November 2020, at the request of the editors, to identify studies published after the previous censor date. Four small studies reporting 3 different outcome measures were identified, which included no data that would alter the findings of the review; they are not included in the meta-analyses. Of 5,290 identified records, 44 were included. Twenty-seven (61%) were RCTs and 17 (39%) were cohort studies. Thirteen studies (30%) reported data from Africa, 12 (27%) from Asia, 6 (14%) from South America, 5 (11%) from North America, and 4 (9%) from Europe. Four studies reported data from multiple continents. Summary estimates suggested smear conversion in 9% of patients at 2 weeks (95% CI 3%-24%, 1 single study [N = 1]), and 82% of patients at 2 months of treatment (95% CI 78%-86%, N = 10). Among baseline smear-positive patients, solid culture conversion occurred by 2 weeks in 5% (95% CI 0%-14%, N = 2), increasing to 88% at 2 months (95% CI 84%-92%, N = 20). At equivalent time points, liquid culture conversion was achieved in 3% (95% CI 1%-16%, N = 1) and 59% (95% CI 47%-70%, N = 8). Significant heterogeneity was observed. Further interrogation of the data to explain this heterogeneity was limited by the lack of disaggregation of results, including by factors such as HIV status, baseline smear status, and the presence or absence of lung cavitation.

CONCLUSIONS

This systematic review found that most patients remained culture positive at 2 weeks of TB treatment, challenging the view that individuals are not infectious after this interval. Culture positivity is, however, only 1 component of infectiousness, with reduced cough frequency and aerosol generation after TB treatment initiation likely to also be important. Studies that integrate our findings with data on cough dynamics could provide a more complete perspective on potential transmission of Mycobacterium tuberculosis by individuals on treatment.

TRIAL REGISTRATION

Systematic review registration: PROSPERO 85226.

Impacts of metformin on tuberculosis incidence and clinical outcomes in patients with diabetes: a systematic review and meta-analysis

BACKGROUND

Accumulating evidence suggested that the use of metformin had more benefits for both prevention and treatment of tuberculosis (TB) than non-metformin use in patients with diabetes mellitus (DM); however, it remains to be fully elucidated on this topic. Thus, we conducted a systematic review and meta-analysis of published studies to determine the association between metformin use and TB in patients with diabetes.

METHODS

The MEDLINE, EMBASE, Information Sciences Institute (ISI) Web of Science, and Cochrane CENTRAL databases were searched from their inception to 15 April 2019. Studies that evaluated the use of metformin and TB disease were included. The quality of each study was evaluated through the Newcastle-Ottawa Scale (NOS). For pooled data, the relative risk (RR) and 95% confidence intervals (CIs) were calculated; otherwise, a systematic review.

RESULTS

Seventeen observational studies were included, all of which indicated a low risk of bias according to the NOS. The pooled analysis showed that metformin use was associated with a significantly lower active TB incidence and mortality among individuals with DM (RR = 0.51; 95% CI, 0.38-0.69, P ⩽ 0.001) and with TB-DM (RR = 0.34; 95% CI, 0.20-0.57, P ⩽ 0.001), respectively.

CONCLUSIONS

This meta-analysis indicated metformin use is related to benefits in both prevention and treatment outcomes of tuberculosis among patients with diabetes. Prospective clinical trials are needed to confirm these associations.