Clinical outcomes of Estonian patients with primary multidrug-resistant versus drug-susceptible tuberculosis

Tuberculosis Pathways to Care and Transmission of Multidrug-Resistance in India

Rationale

India is experiencing a regional increase in cases of multidrug-resistant tuberculosis (MDR-TB).

Objectives

Given the complexity of MDR-TB diagnosis and care, we sought to address key knowledge gaps in MDR risk factors, care delays, and drivers of delay to help guide disease control.

Methods

From January 2018 to September 2019, we conducted interviews with adults registered with the National TB Elimination Program for MDR (n = 128) and non–MDR-TB (n = 269) treatment to quantitatively and qualitatively study care pathways. We collected treatment records and GeneXpert-TB/RIF diagnostic reports.

Measurements and Main Results

MDR-TB was associated with young age and crowded residence. GeneXpert rifampicin resistance diversity was measured at 72.5% Probe E. Median time from symptom onset to diagnosis of MDR was 90 days versus 60 days for non-MDR, Wilcoxon P < 0.01. Delay decreased by a median of 30 days among non-MDR patients with wider access to GeneXpert, Wilcoxon P = 0.02. Pathways to care were complex, with a median (interquartile range) of 4 (3–5) and 3 (2–4) encounters for MDR and non-MDR, respectively. Of patients with MDR-TB, 68% had their first encounter in the private sector, and this was associated with a larger number of subsequent healthcare encounters and catastrophic expenditure.

Conclusions

The association of MDR with young age, crowding, and low genotypic diversity raises concerns of ongoing MDR transmission fueled by long delays in care. Delays are decreasing with GeneXpert use, suggesting the need for routine use in presumptive TB. Qualitatively, we identify the need to improve patient retention in the National TB Elimination Program and highlight patients’ trust relationship with private providers.

Rifampicin-resistant Mycobacterium tuberculosis by GeneXpert MTB/RIF and Associated Factors Among Presumptive Pulmonary Tuberculosis Patients in Nepal

Background

Mycobacterium tuberculosis(MTB) remains a major public health problem worldwide, and emergence of drug-resistant TB has become a significant obstacle to effective TB control. However, the rate of MTB and rifampicin resistant-MTB (RR-MTB) in the Nepalese setting has not been studied extensively. Therefore, the present study aims to assess the rate of MTB and RR-MTB and further determine the factors associated with it.

Methods

A retrospective cross-sectional study, among national representative data of 990 consecutive presumptive TB resister of patients subjected to the GeneXpert test that presented to the tuberculosis referral hospital, was conducted over a one year period from February 2018 to January 2019. Significance for the difference for categorical data was performed by Chi-square test and factors associated with MTB and RR-MTB were assessed using binary logistic regression yielding OR with 95%CI.

Results

Of total 990 presumptive tuberculosis analyzed cases, median ages of the patients were 39±19.09 years and two-thirds of the patients were male 653 (66.0%). The estimated prevalence of MTB in presumptive TB patients was 13.8% (95%CI: 11.88%–16.16%), and risk for MTB was significantly associated with previously treated patients: OR: 10.4 (P<0.001). The estimated prevalence of RR-MTB in MTB confirmed patients was 10.2% (4.97%–15.1%). Our study confirmed no association of RR-TB with age, sex, ethnicity, geographical diversity and previous history of treatment failure (P>0.05).

Conclusion

The overall prevalence of MTB and RR-MTB was high in Nepalese study population,  and that being previously treated with anti-TB drug remained significant predictors for MTB; proactive measures are urgently needed to address the challenge of prompt diagnosis, early management and improved monitoring of treatment to limit the emergence drug-resistant MTB strains in the community.

Outcome Impacts Due to Pathogen-Specific Antimicrobial Resistance: A Narrative Review of Published Literature

Antimicrobial resistance (AMR) has become a global threat to not only public health impacts but also clinical and economic outcomes. During the past decades, there have been many studies focusing on surveillance, mechanisms, and diagnostics of AMR in infectious diseases but the impacts on public health, clinical and economic outcomes due to emergence of these AMRs are rarely studied and reported. This review was aimed to summarize the findings from published studies to report the outcome impacts due to AMR of malaria, tuberculosis and HIV and briefly discuss the implications for application to other infectious diseases. PubMed/Medline and Google Scholar databases were used for search of empirical and peer-reviewed papers reporting public health, clinical and economic outcomes due to AMR of malaria, tuberculosis and HIV. Papers published through 1 December 2019 were included in this review. A total of 76 studies were included for this review, including 16, 49 and 11 on public health, clinical and economic outcomes, respectively. The synthesized data indicated that the emergence and spread of AMR of malaria, tuberculosis and HIV have resulted in adverse public health, clinical and economic outcomes. AMR of malaria, tuberculosis and HIV results in significant adverse impacts on public health, clinical and economic outcomes. Evidence from this review suggests the needs to consider the similar studies for other infectious diseases.

Prevalence of rifampicin resistant Mycobacterium tuberculosis among presumptive tuberculosis patients in selected governmental hospitals in Addis Ababa, Ethiopia

BACKGROUND

Rapid detection of rifampicin resistance is essential for early management and prevention of transmission of multidrug-resistant tuberculosis (MDR-TB). We studied the prevalence of rifampicin resistance of Mycobacterium tuberculosis (MTB) among presumptive TB patients in Addis Ababa, Ethiopia.

METHODS

A retrospective cross sectional study was conducted in three referral hospitals and the regional laboratory in Addis Ababa city from March 2015 to October 2017. Data was collected by data-extraction sheet from registration books. It was analyzed using SPSS version 20. Statistically significant association was taken with P < 0.05.

RESULTS

A total of 12,414 (11,672 adults and 742 paediatrics) TB presumptive patients were included in the study. The overall prevalence of TB was 15.11% (1876/12414) in all age groups and 13.6%(101/742) among paediatric population. Rifampicin resistant TB was 9.9% (186/1876) in all TB confirmed cases and 7.9% (8/101) in paediatric TB patients. The prevalence of rifampicin resistant TB among new and previously treated was 7.6 and 27.4%, respectively. Sex (being female) and previous TB treatment were significantly associated with rifampicin resistant TB.

CONCLUSIONS

Rifampicin-resistant TB is prevalent both among adult and paediatric TB patients. The strong association of rifampicin resistance with previous treatment in this study suggests the need to improve and monitor the treatment to limit the emergence of drug resistant TB.

Models for Predicting Time to Sputum Conversion Among Multi-Drug Resistant Tuberculosis Patients in Lagos, South-West Nigeria

Background: Multi-drug resistant tuberculosis (MDR-TB) develops due to problems such as irregular drug supply, poor drug quality, inappropriate prescription, and poor adherence to treatment. These factors allow the development and subsequent transmission of resistant strains of the pathogen. However, due to the chronic nature of MDR-TB, cure models allow us to investigate the covariates that are associated with the long-term effects of time-to-sputum conversion among multi-drug resistant (MDR-TB) tuberculosis individuals. Therefore, this study was designed to develop suitable cure models that can predict time to sputum conversion among MDR-TB patients. Methods: A retrospective clinic-based cohort study was conducted on 413 records of patients who were diagnosed of MDR-TB and met inclusion criteria from April 2012 to October 2016 at the Infectious Disease Hospital, Lagos. The main outcome measure (time-to-sputum conversion) was the time from the date of MDR-TB treatment to the date of specimen collection for the first of two consecutive negative smear and culture taken 30 days apart. The predictor variables of interest include: demographic (age, gender and marital status) and clinical (registration group, number of drugs resistant to at treatment initiation, HIV status, diabetes status, and adherence with medication) characteristics. Kaplan-Meier estimates of a detailed survivorship pattern among the patients were examined using Cox regression models. Mixture Cox cure models were fitted to the main outcome variable using Log-normal, Log-logistic and Weibull models as alternatives to the violation of Proportional Hazard (PH) assumption. Akaike Information Criterion (AIC) was used for models comparison based on different distributions, while the effect of predictors of time to sputum conversion was reported as Hazard Ratio (HR) at α0.05. Results: Age was 36.8 ± 12.7 years, 60.8% were male and 67.6% were married. Majority of the patients (58.4%) converted to sputum negatives. Patients who were resistant to two drugs at treatment initiation had 39% rate of conversion than those resistant to at least three drugs [HR: 1.39; CI: 0.98, 1.98]. The likelihood of sputum conversion time was shorter among non-diabetic patients compared to diabetics [HR: 0.55; CI: 0.24, 0.85]. The overall median time for sputum conversion was 5.5 (IQR: 1.5-11.5). In the cure model, resistance to more drugs at the time of initiation was significantly associated with a longer time to sputum culture conversion for Log normal Cox mixture [2.06 (1.36-3.47)]; Log-logistic Cox mixture cure [2.56(1.85-4.09)]; and Weibull Cox mixture [2.81(1.94-4.19)]. Diabetic patients had a significantly higher sputum conversion rate compared to non-diabetics; Log-normal Cox mixture [2.03(1.17-3.58)]; Log-logistic Cox mixture cure [2.11(1.25-3.82)]; and Weibull Cox mixture [2.02(1.17-3.34)]. However, Log-normal PH model gave the best fit and provided the fitness statistics [(-2LogL: 519.84); (AIC: 1053.68); (BIC: 1078.04)]. The best fitting Log-normal PH model was Y = 1.00X1+2.06X2+0.98X3+2.03X4+ε where Y is time to sputum conversion and Xs are age, number of drugs, adherence, and diabetes status. Conclusion: The models confirmed the presence of some factors related with sputum conversion time in Nigeria. The quantum of drugs resistant at treatment initiation and diabetes status would aid the clinicians in predicting the rate of sputum conversion of patients.

Treatment correlates of successful outcomes in pulmonary multidrug-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Treatment outcomes for multidrug-resistant tuberculosis remain poor. We aimed to estimate the association of treatment success and death with the use of individual drugs, and the optimal number and duration of treatment with those drugs in patients with multidrug-resistant tuberculosis.

METHODS

In this individual patient data meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library to identify potentially eligible observational and experimental studies published between Jan 1, 2009, and April 30, 2016. We also searched reference lists from all systematic reviews of treatment of multidrug-resistant tuberculosis published since 2009. To be eligible, studies had to report original results, with end of treatment outcomes (treatment completion [success], failure, or relapse) in cohorts of at least 25 adults (aged >18 years). We used anonymised individual patient data from eligible studies, provided by study investigators, regarding clinical characteristics, treatment, and outcomes. Using propensity score-matched generalised mixed effects logistic, or linear regression, we calculated adjusted odds ratios and adjusted risk differences for success or death during treatment, for specific drugs currently used to treat multidrug-resistant tuberculosis, as well as the number of drugs used and treatment duration.

FINDINGS

Of 12 030 patients from 25 countries in 50 studies, 7346 (61%) had treatment success, 1017 (8%) had failure or relapse, and 1729 (14%) died. Compared with failure or relapse, treatment success was positively associated with the use of linezolid (adjusted risk difference 0·15, 95% CI 0·11 to 0·18), levofloxacin (0·15, 0·13 to 0·18), carbapenems (0·14, 0·06 to 0·21), moxifloxacin (0·11, 0·08 to 0·14), bedaquiline (0·10, 0·05 to 0·14), and clofazimine (0·06, 0·01 to 0·10). There was a significant association between reduced mortality and use of linezolid (-0·20, -0·23 to -0·16), levofloxacin (-0·06, -0·09 to -0·04), moxifloxacin (-0·07, -0·10 to -0·04), or bedaquiline (-0·14, -0·19 to -0·10). Compared with regimens without any injectable drug, amikacin provided modest benefits, but kanamycin and capreomycin were associated with worse outcomes. The remaining drugs were associated with slight or no improvements in outcomes. Treatment outcomes were significantly worse for most drugs if they were used despite in-vitro resistance. The optimal number of effective drugs seemed to be five in the initial phase, and four in the continuation phase. In these adjusted analyses, heterogeneity, based on a simulated I² method, was high for approximately half the estimates for specific drugs, although relatively low for number of drugs and durations analyses.

INTERPRETATION

Although inferences are limited by the observational nature of these data, treatment outcomes were significantly better with use of linezolid, later generation fluoroquinolones, bedaquiline, clofazimine, and carbapenems for treatment of multidrug-resistant tuberculosis. These findings emphasise the need for trials to ascertain the optimal combination and duration of these drugs for treatment of this condition.

FUNDING

American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Time to sputum culture conversion and treatment outcome among the first cohort of multidrug resistant tuberculosis patients in a high burden country

BACKGROUND

Sputum conversion considered the most important interim indicator of the efficacy of anti-tuberculosis treatment was assessed at varying time points among the first cohort of multidrug resistant tuberculosis (MDR-TB) patients in a National TB Control Programme.

METHODS

A retrospective study was conducted for the period between 2010 and 2013, at the premiere MDR-TB treatment center in Nigeria. Genexpert, culture and drug susceptibility tests were carried out. Total duration of treatment was 20 months.

RESULTS

A total of 115 patients were studied consisting of 76 (66.1%) males and 39 (33.9%) females with ages ranging between 15 and 65 years. Median time to sputum conversion was 2.06 months (95% confident interval [CI] = 1.82, 2.30). At the end of the first month, 43 (37.4%) patients sputum converted, increasing to 104 (90.4%) at the end of three months. There was no significant interaction with Human Immunodeficiency Virus (HIV) status. Overall treatment success was 69.4%. The default rate was 8.7% (10/115) and 25 (21.7%) deaths were recorded.

CONCLUSION

The treatment success rate in the study was high with most of cases with or without HIV infection, achieving sputum culture conversion within 2 months of commencing treatment. Expansion of MDR-TB treatment services is necessary to reduce the death rate.

Treatment outcome among cases of multidrug-resistant tuberculosis (MDR TB) in Western India: A prospective study

Multidrug-resistant TB has become a significant public health problem in a number of countries and an obstacle to effective TB control. Therefore, the present study sought to determine the treatment outcome in patients with MDR TB in seven districts and to examine the factors affecting the treatment outcome. A prospective cohort study was carried out by enrolling all the registered patients in DOTs Plus center of Vadodara district from February 2010 to December 2010. A total of 142 patients were interviewed using a pre-tested semi-structured questionnaire at the DOTS centers of seven districts of Gujarat or at their homes in cases of defaulters/death. After 24 months, of those 145 patients, 48 (33.10%) were declared cured, 8 (5.50%) had completed their treatment, 43 (29.70%) patients died during the treatment, and 32 (21.10%) patients defaulted during treatment. Factors associated with a significant difference in the outcomes were income, marital status, and education. Only education significantly affected treatment outcome upon applying logistic regression. Therefore, proper counseling on drug adherence should be applied at the programmatic level.

Mortality among MDR-TB cases: comparison with drug-susceptible tuberculosis and associated factors

Background

An increase in multidrug-resistant tuberculosis (MDR-TB) cases is evident worldwide. Its management implies a complex treatment, high costs, more toxic anti-tuberculosis drug use, longer treatment time and increased treatment failure and mortality. The aims of this study were to compare mortality between MDR and drug-susceptible cases of tuberculosis, and to determine risk factors associated with mortality among MDR-TB cases.

Methods and Results

A retrospective cohort study was performed using data from clinical records of the National Strategy for Prevention and Control of Tuberculosis in Lima, Peru. In the first objective, MDR-TB, compared to drug-susceptible cases, was the main exposure variable and time to death, censored at 180 days, the outcome of interest. For the second objective, different variables obtained from clinical records were assessed as potential risk factors for death among MDR-TB cases. Cox regression analysis was used to determine hazard ratios (HR) and 95% confidence intervals (95%CI). A total of 1,232 patients were analyzed: mean age 30.9 ±14.0 years, 60.0% were males. 61 patients (5.0%) died during treatment, whereas the MDR-TB prevalence was 19.2%. MDR-TB increased the risk of death during treatment (HR = 7.5; IC95%: 4.1–13.4) when compared to presumed drug-susceptible cases after controlling for potential confounders. Education level (p = 0.01), previous TB episodes (p<0.001), diabetes history (p<0.001) and HIV infection (p = 0.04) were factors associated with mortality among MDR-TB cases.

Conclusions

MDR-TB is associated with an increased risk of death during treatment. Lower education, greater number of previous TB episodes, diabetes history, and HIV infection were independently associated with mortality among MDR-TB cases. New strategies for appropriate MDR-TB detection and management should be implemented, including drug sensitivity tests, diabetes and HIV screening, as well as guarantee for a complete adherence to therapy.

Treatment outcomes of patients with multidrug-resistant and extensively drug-resistant tuberculosis according to drug susceptibility testing to first- and second-line drugs: an individual patient data meta-analysis

BACKGROUND

Individualized treatment for multidrug-resistant (MDR) tuberculosis and extensively drug-resistant (XDR) tuberculosis depends upon reliable and valid drug susceptibility testing (DST) for pyrazinamide, ethambutol, and second-line tuberculosis drugs. However, the reliability of these tests is uncertain, due to unresolved methodological issues. We estimated the association of DST results for pyrazinamide, ethambutol, and second-line drugs with treatment outcomes in patients with MDR tuberculosis and XDR tuberculosis.

METHODS

We conducted an analysis of individual patient data assembled from 31 previously published cohort studies of patients with MDR and XDR tuberculosis. We used data on patients' clinical characteristics including DST results, treatment received, outcomes, and laboratory methods in each center.

RESULTS

DST methods and treatment regimens used in different centers varied considerably. Among 8955 analyzed patients, in vitro susceptibility to individual drugs was consistently and significantly associated with higher odds of treatment success (compared with resistance to the drug), if that drug was used in the treatment regimen. Various adjusted and sensitivity analyses suggest that this was not explained by confounding. The adjusted odds of treatment success for ethambutol, pyrazinamide, and the group 4 drugs ranged from 1.7 to 2.3, whereas for second-line injectables and fluoroquinolones, odds ranged from 2.4 to 4.6.

CONCLUSIONS

DST for ethambutol, pyrazinamide, and second-line tuberculosis drugs appears to provide clinically useful information to guide selection of treatment regimens for MDR and XDR tuberculosis.

Rates and risk factors for drug resistance tuberculosis in Northeastern China

BACKGROUND

Drug-resistant tuberculosis (TB) has emerged as a major challenge toward TB control and prevention. In Lianyungang city, the extent and trend of drug resistant TB is not well known. The objective of the survey was to assess drug resistance pattern of MTB and risk factors for drug resistant TB, including multidrug resistance tuberculosis (MDR-TB) in this area.

METHODS

We performed drug susceptibility testing on Mycobacterium tuberculosis (MTB) isolates with first- and second-line anti-tuberculosis drugs of 1012 culture positive TB cases by using the proportion method, who were consecutively enrolled from January 2011 to December 2012 in Lianyungang city, China. The patterns of drug resistance in MTB were investigated and multiple logistic regression analysis was performed to assess the risk factors for drug resistant TB.

RESULTS

Among the 1012 strains tested, 308 (30.4%) strains were resistant to at least one first-line drug; the prevalence of MDR-TB was 88 (8.7%), 5 (0.5%) strains were found to be extensively drug-resistant tuberculosis (XDR-TB). Female gender was a risk factor for MDR-TB (adjusted odds ratio (aOR) 1.763, 95% CI (1.060-2.934). The aged 28-54 years was significantly associated with the risk of MDR-TB with an aOR: 2.224, 95% CI (1.158-4.273) when compared with those 65 years or older. Patients with previous treatment history had a more than 7-fold increased risk of MDR-TB, compared with those never previously treated.

CONCLUSIONS

The burden of drug resistant TB cases is sizeable, which highlights an urgent need to reinforce control, detection and treatment strategies for drug resistant TB.

Tuberculosis treatment outcome monitoring in European Union countries: systematic review

Treatment success measured by treatment outcome monitoring (TOM) is a key programmatic output of tuberculosis (TB) control programmes. We performed a systematic literature review on national-level TOM in the 30 European Union (EU)/European Economic Areas (EEA) countries to summarise methods used to collect and report data on TOM. Online reference bibliographic databases PubMed/MEDLINE and EMBASE were searched to identify relevant indexed and non-indexed literature published between January 2000 and August 2010. The search strategy resulted in 615 potentially relevant indexed citations, of which 27 full-text national studies (79 data sets) were included for final analysis. The selected studies were performed in 10 EU/EEA countries and gave a fragmented impression of TOM in the EU/EEA. Publication year, study period, sample size, databases, definitions, variables, patient and outcome categories, and population subgroups varied widely, portraying a very heterogeneous picture. This review confirmed previous reports of considerable heterogeneity in publications of TOM results across EU/EEA countries. PubMed/MEDLINE and EMBASE indexed studies are not a suitable instrument to measure representative TOM results for the 30 EU/EEA countries. Uniform and complete reporting to the centralised European Surveillance System will produce the most timely and reliable results of TB treatment outcomes in the EU/EEA.

Resistance to fluoroquinolones and second-line injectable drugs: impact on multidrug-resistant TB outcomes

A meta-analysis for response to treatment was undertaken using individual data of multidrug-resistant tuberculosis (MDR-TB) (resistance to isoniazid and rifampicin) patients from 26 centres. The analysis assessed the impact of additional resistance to fluoroquinolones and/or second-line injectable drugs on treatment outcome. Compared with treatment failure, relapse and death, treatment success was higher in MDR-TB patients infected with strains without additional resistance (n=4763; 64%, 95% CI 57-72%) or with resistance to second-line injectable drugs only (n=1130; 56%, 95% CI 45-66%), than in those having resistance to fluoroquinolones alone (n=426; 48%, 95% CI 36-60%) or to fluoroquinolones plus second-line injectable drugs (extensively drug resistant (XDR)-TB) (n=405; 40%, 95% CI 27-53%). In XDR-TB patients, treatment success was highest if at least six drugs were used in the intensive phase (adjusted OR 4.9, 95% CI 1.4-16.6; reference fewer than three drugs) and four in the continuation phase (OR 6.1, 95% CI 1.4-26.3). The odds of success in XDR-TB patients was maximised when the intensive phase reached 6.6-9.0 months duration and the total duration of treatment 20.1-25.0 months. In XDR-TB patients, regimens containing more drugs than those recommended in MDR-TB but given for a similar duration were associated with the highest odds of success. All data were from observational studies and methodologies varied between centres, therefore, the bias may be substantial. Better quality evidence is needed to optimise regimens.

Comparing early treatment outcomes of MDR-TB in decentralised and centralised settings in KwaZulu-Natal, South Africa

SETTING

In KwaZulu-Natal, South Africa, a setting endemic for tuberculosis (TB) and the human immunodeficiency virus (HIV), prolonged hospitalisation for the treatment of the growing number of multidrug-resistant TB (MDR-TB) patients is neither possible nor effective.

OBJECTIVE

To compare early treatment outcomes in patients with MDR-TB with and without HIV co-infection at four decentralised rural sites with a central urban referral hospital.

DESIGN

This is an operational, prospective cohort study of patients between 1 July 2008 and 30 November 2009, where culture conversion, time to culture conversion, survival and predictors of these outcomes were analysed.

RESULTS

Of 860 patients with MDR-TB, 419 were at the decentralised sites and 441 at the central hospital. Overall, 71% were HIV co-infected. In the 17-month study period, there was a higher proportion of culture conversion at the decentralised sites compared with the centralised hospital (54% vs. 24%, P < 0.001, OR 3.76, 95%CI 2.81-5.03). The median time to treatment initiation was significantly shorter at the decentralised sites compared with the centralised hospital (72 vs. 93 days, P < 0.001). There was no significant difference in survival following treatment initiation.

CONCLUSION

In this study, early treatment outcomes suggest that decentralised care for MDR-TB patients is superior to that in a centralised setting.

Multidrug resistant pulmonary tuberculosis treatment regimens and patient outcomes: an individual patient data meta-analysis of 9,153 patients

BACKGROUND

Treatment of multidrug resistant tuberculosis (MDR-TB) is lengthy, toxic, expensive, and has generally poor outcomes. We undertook an individual patient data meta-analysis to assess the impact on outcomes of the type, number, and duration of drugs used to treat MDR-TB.

METHODS AND FINDINGS

Three recent systematic reviews were used to identify studies reporting treatment outcomes of microbiologically confirmed MDR-TB. Study authors were contacted to solicit individual patient data including clinical characteristics, treatment given, and outcomes. Random effects multivariable logistic meta-regression was used to estimate adjusted odds of treatment success. Adequate treatment and outcome data were provided for 9,153 patients with MDR-TB from 32 observational studies. Treatment success, compared to failure/relapse, was associated with use of: later generation quinolones, (adjusted odds ratio [aOR]: 2.5 [95% CI 1.1-6.0]), ofloxacin (aOR: 2.5 [1.6-3.9]), ethionamide or prothionamide (aOR: 1.7 [1.3-2.3]), use of four or more likely effective drugs in the initial intensive phase (aOR: 2.3 [1.3-3.9]), and three or more likely effective drugs in the continuation phase (aOR: 2.7 [1.7-4.1]). Similar results were seen for the association of treatment success compared to failure/relapse or death: later generation quinolones, (aOR: 2.7 [1.7-4.3]), ofloxacin (aOR: 2.3 [1.3-3.8]), ethionamide or prothionamide (aOR: 1.7 [1.4-2.1]), use of four or more likely effective drugs in the initial intensive phase (aOR: 2.7 [1.9-3.9]), and three or more likely effective drugs in the continuation phase (aOR: 4.5 [3.4-6.0]).

CONCLUSIONS

In this individual patient data meta-analysis of observational data, improved MDR-TB treatment success and survival were associated with use of certain fluoroquinolones, ethionamide, or prothionamide, and greater total number of effective drugs. However, randomized trials are urgently needed to optimize MDR-TB treatment. Please see later in the article for the Editors' Summary.

High Frequency of First-Line Anti-Tuberculosis Drug Resistance among Persons with Chronic Pulmonary Tuberculosis at a Teaching Hospital Chest Clinic

INTRODUCTION

The burden of MDR-TB is unknown in areas that do not have drug susceptibility testing (DST), but its frequency is expected to be higher in previously treated cases. Where DST is not available the WHO recommended standardized retreatment (Category II) regimen is given to previously treated TB patients

OBJECTIVE

To evaluate the frequency and pattern of drug resistance of Mycobacterium tuberculosis isolated from patients with chronic smear positive pulmonary tuberculosis.

METHOD

We conducted a retrospective review of mycobacterial cultures and drug susceptibility testing (DST) performed on sputum samples collected, between January 2005 and September 2006, from 40 patients with pulmonary TB who had failed at least one standard retreatment regimen. Clinical data was extracted from patients' case notes.

RESULTS

M. tuberculosis was recovered from 28 (70%) of the 40 patients. Of the 28 culture positive cases, 10 (36%) had resistance to at least rifampicin and isoniazid (multi-drug resistant TB), 22 (79%) isolates had resistance to streptomycin and 13 (46%) to ethambutol. Of the patients with a positive culture, only one (3.6%) had a fully susceptible organism. Of the 10 patients with MDR TB, 7 had received two or more retreatment courses.

CONCLUSION

The frequency of drug resistant TB was high among patients who failed at least one course of category II therapy. Effective combination regimens based on DST is necessary in patients who remain smear positive on the standardized retreatment regimen.

Multidrug-resistant and extensively drug-resistant tuberculosis: a review

PURPOSE OF REVIEW

The spread of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant TB (XDR-TB) is a major medical and public health concern for the world. These two forms of highly drug-resistant TB threaten to make TB into an untreatable and highly fatal disease, particularly in resource-poor countries with a high prevalence of AIDS. The focus of this review is to highlight the current extent of the problem.

RECENT FINDINGS

There is a great variability in clinical outcomes for MDR-TB, in part due to differences in the definitions of outcome measures and retrospective nature of the studies. Outcomes for XDR-TB are uniformly worse than those for MDR-TB.

SUMMARY

A multifaceted approach is needed to prevent a more widespread epidemic of MDR-TB and XDR-TB. Rapid diagnostic assays to detect highly drug-resistant TB are essential in preventing delays in treatment of MDR-TB and XDR-TB and curbing their spread. Development of new drugs to effectively treat all forms of TB in a shorter period of time is urgently needed.

High prevalence of multidrug-resistant tuberculosis in Georgia

BACKGROUND

Tuberculosis (TB) has emerged as a serious public health problem in the country of Georgia. However, little or no data exist on rates and risk factors for drug-resistant TB, including multidrug-resistant (MDR)-TB, in Georgia.

OBJECTIVE

To assess the prevalence and risk factors for drug-resistant TB.

METHODS

A cross-sectional prospective survey of patients with suspected pulmonary TB was carried out at four sentinel sites (Tbilisi, Zugdidi, Kutaisi, and Batumi) in Georgia between January 1, 2001 and December 31, 2004.

RESULTS

Among 1422 patients with suspected pulmonary TB, 996 (70.0%) were culture positive; 931/996 (93.5%) had drug susceptibility testing performed. Overall, 64.0% of patients (48.3% of new and 85.3% of retreatment cases) had positive cultures for Mycobacterium tuberculosis resistant to >or=1 first-line antituberculosis drugs. The overall prevalence of MDR-TB was 28.1% (10.5% of newly diagnosed patients and 53.1% of retreatment cases). In multivariate analysis, risk factors for MDR-TB included: being a retreatment case (prevalence ratio (PR)=5.28, 95% CI 3.95-7.07), history of injection drug use (PR=1.59, 95% CI 1.21-2.09), and female gender (PR=1.36, 95% CI 1.12-1.65).

CONCLUSIONS

MDR-TB has emerged as a serious public health problem in Georgia and will greatly impact TB control strategies.

Impact of joined-up HIV harm reduction and multidrug resistant tuberculosis control programmes in Estonia: System dynamics simulation model

In Eastern Europe and Central Asia (ECA) the control of tuberculosis, multidrug resistant tuberculosis (MDRTB) and human immunodeficiency virus (HIV) poses important public health challenges. We used system dynamics simulation to determine impact on cumulative HIV/AIDS, tuberculosis and HIV-associated-tuberculosis deaths, over 20 years, of harm-reduction programmes to reduce needle-sharing and injection-frequency amongst injecting drug users (IDUs) and multidrug resistant tuberculosis (MDRTB) control in a population with an explosive HIV epidemic in IDUs and high MDRTB prevalence. We estimate that the number of HIV-associated-deaths will decline by 30% with effective harm-reduction programmes but double if these are ineffective. In our model, effective MDRTB and HIV control reduces cumulative tuberculosis deaths by 54%, cumulative MDRTB deaths 15-fold and cumulative HIV-associated-tuberculosis-deaths 2-fold. Effective MDRTB control, without effective harm-reduction programmes, only reduce tuberculosis deaths by 22%. However, effective harm-reduction programme with a poor MDRTB control reduce cumulative tuberculosis deaths by 34%, MDRTB by 14% and HIV-associated-tuberculosis by 56%. Even with good control programmes for drug sensitive TB, neglecting harm reduction and MDRTB control will result in 50% more tuberculosis-related deaths than if both are effectively addressed. Effective harm-reduction programmes reduces cumulative deaths from tuberculosis more substantively than effective MDRTB control. Our finding have important policy implications for communicable disease policies in post-Soviet countries, which need to substantially change if they are to effectively address the emerging HIV and MDRTB epidemics.

Risk factors for multidrug resistant tuberculosis in Europe: a systematic review

BACKGROUND

The resurgence of tuberculosis (TB) in western countries has been attributed to the HIV epidemic, immigration, and drug resistance. Multidrug resistant tuberculosis (MDR-TB) is caused by the transmission of multidrug resistant Mycobacterium tuberculosis strains in new cases, or by the selection of single drug resistant strains induced by previous treatment. The aim of this report is to determine risk factors for MDR-TB in Europe.

METHODS

A systematic review was conducted of published reports of risk factors associated with MDR-TB in Europe. Meta-analysis, meta-regression, and sub-grouping were used to pool risk estimates of MDR-TB and to analyse associations with age, sex, immigrant status, HIV status, occurrence year, study design, and area of Europe.

RESULTS

Twenty nine papers were eligible for the review from 123 identified in the search. The pooled risk of MDR-TB was 10.23 times higher in previously treated than in never treated cases, with wide heterogeneity between studies. Study design and geographical area were associated with MDR-TB risk estimates in previously treated patients; the risk estimates were higher in cohort studies carried out in western Europe (RR 12.63; 95% CI 8.20 to 19.45) than in eastern Europe (RR 8.53; 95% CI 6.57 to 11.06). National estimates were possible for six countries. MDR-TB cases were more likely to be foreign born (odds ratio (OR) 2.46; 95% CI 1.86 to 3.24), younger than 65 years (OR 2.53; 95% CI 1.74 to 4.83), male (OR 1.38; 95% CI 1.16 to 1.65), and HIV positive (OR 3.52; 95% CI 2.48 to 5.01).

CONCLUSIONS

Previous treatment was the strongest determinant of MDR-TB in Europe. Detailed study of the reasons for inadequate treatment could improve control strategies. The risk of MDR-TB in foreign born people needs to be re-evaluated, taking into account any previous treatment.

Epidemic of tuberculosis in the former Soviet Union: social and biological reasons

The tuberculosis epidemic was evidenced in the states of the former Soviet Union at the end of the 20th century. The increase of epidemiological indicators for tuberculosis was accelerated by socio-economic changes in the society. Laboratory analysis also revealed new biological properties of the Mycobacterium tuberculosis isolates in the region, in particular the high level of resistance to antibiotics. Tuberculosis in Russia and the other newly independent states has been caused by M. tuberculosis strains of the W-Beijing family in recent years. These bacteria have rapidly developed resistance to anti-tuberculosis drugs, as a result of prolonged exposure of the patients to inappropriate treatment. The epidemic of drug-resistant tuberculosis caused by the W-Beijing strains represents an important threat to the health of the populations in the newly independent states. It may also adversely affect the global trends in tuberculosis, as there is a clear risk that these drug-resistant strains can spread to other communities outside the former Soviet Union.

Clinical outcome of individualised treatment of multidrug-resistant tuberculosis in Latvia: a retrospective cohort study

BACKGROUND

Latvia has one of the highest rates of multidrug-resistant tuberculosis (MDRTB). Our aim was to assess treatment outcomes for the first full cohort of MDRTB patients treated under Latvia's DOTS-Plus strategy following WHO guidelines.

METHODS

We retrospectively reviewed all civilian patients who began treatment with individualised treatment regimens for pulmonary MDRTB in Latvia between Jan 1, and Dec 31, 2000. We applied treatment outcome definitions for MDRTB, developed by an international expert consensus group, and assessed treatment effectiveness and risk factors associated with poor outcome.

FINDINGS

Of the 204 patients assessed, 55 (27%) had been newly diagnosed with MDRTB, and 149 (73%) had earlier been treated with first-line or second-line drugs for this disease. Assessment of treatment outcomes showed that 135 (66%) patients were cured or completed therapy, 14 (7%) died, 26 (13%) defaulted, and treatment failed in 29 (14%). Of the 178 adherent patients, 135 (76%) achieved cure or treatment completion. In a multivariate Cox proportional-hazards model of these patients, independent predictors of poor outcome (death and treatment failure) included having previously received treatment for MDRTB (hazard ratio 5.7, 95% CI 1.9-16.6), the use of five or fewer drugs for 3 months or more (3.2, 1.1-9.6), resistance to ofloxacin (2.6, 1.2-5.4), and body-mass index less than 18.5 at start of treatment (2.3, 1.1-4.9).

INTERPRETATION

The DOTS-Plus strategy of identifying and treating patients with MDRTB can be effectively implemented on a nationwide scale in a setting of limited resources.

Multidrug-resistant tuberculosis in central Asia

Multidrug-resistant tuberculosis (MDR-TB) has emerged as a major threat to TB control, particularly in the former Soviet Union. To determine levels of drug resistance within a directly observed treatment strategy (DOTS) program supported by Médecins Sans Frontières in two regions in Uzbekistan and Turkmenistan, Central Asia, we conducted a cross-sectional survey of smear-positive TB patients in selected districts of Karakalpakstan (Uzbekistan) and Dashoguz (Turkmenistan). High levels of MDR-TB were found in both regions. In Karakalpakstan, 14 (13%) of 106 new patients were infected with MDR-TB; 43 (40%) of 107 previously treated patients were similarly infected. The proportions for Dashoguz were 4% (4/105 patients) and 18% (18/98 patients), respectively. Overall, 27% of patients with positive smear results whose infections were treated through the DOTS program in Karakalpakstan and 11% of similar patients in Dashoguz were infected with multidrug-resistant strains of TB on admission. These results show the need for concerted action by the international community to contain transmission and reduce the effects of MDR-TB.