Irina Y. Gelmanova

Treatment of extensively drug-resistant tuberculosis in Tomsk, Russia: a retrospective cohort study

BACKGROUND Mycobacterium tuberculosis strains that cause untreatable drug-resistant disease are a threat worldwide. We describe the treatment, management, and outcomes of patients with extensively drug-resistant tuberculosis in Tomsk, Russia. METHODS We undertook a retrospective cohort study of 608 patients with multidrug resistant tuberculosis who had treatment in civilian or prison services, between Sept 10, 2000, and Nov 1, 2004, according to the treatment strategy recommended by WHO. Clinical characteristics, management practices, and treatment outcomes of patients with extensively drug-resistant (XDR) tuberculosis and non-extensively drug-resistant (non-XDR) tuberculosis are described. The main outcome was the frequency of poor and favourable outcomes at the end of treatment. FINDINGS Of 608 patients with multidrug resistant tuberculosis, 29 (4.8%) patients had baseline XDR tuberculosis. Treatment failure was more common in patients with XDR tuberculosis than in those with non-XDR tuberculosis (31%vs 8.5%, p=0.0008). 48.3% of patients with XDR tuberculosis and 66.7% of patients with non-XDR tuberculosis had treatment cure or completion (p=0.04). The frequency and management of adverse events did not differ between patients with XDR and non-XDR tuberculosis. INTERPRETATION The chronic features of tuberculosis in these patients suggest that extensively drug-resistant tuberculosis may be acquired through previous treatments that include second-line drugs. Aggressive management of this infectious disease is feasible and can prevent high mortality rates and further transmission of drug-resistant strains of Mycobacterium tuberculosis.

Barriers to successful tuberculosis treatment in Tomsk, Russian Federation: non-adherence, default and the acquisition of multidrug resistance

OBJECTIVE To identify barriers to successful tuberculosis (TB) treatment in Tomsk, Siberia, by analysing individual and programmatic risk factors for non-adherence, default and the acquisition of multidrug resistance in a TB treatment cohort in the Russian Federation. METHODS We conducted a retrospective cohort study of consecutively enrolled, newly detected, smear and/or culture-positive adult TB patients initiating therapy in a DOTS programme in Tomsk between 1 January and 31 December 2001. FINDINGS Substance abuse was strongly associated with non-adherence [adjusted odds ratio (OR): 7.3; 95% confidence interval (CI): 2.89-18.46] and with default (adjusted OR: 11.2; 95% CI: 2.55-49.17). Although non-adherence was associated with poor treatment outcomes (OR: 2.4; 95% CI: 1.1-5.5), it was not associated with the acquisition of multi-drug resistance during the course of therapy. Patients who began treatment in the hospital setting or who were hospitalized later during their treatment course had a substantially higher risk of developing multidrug-resistant TB than those who were treated as outpatients (adjusted HRs: 6.34; 95% CI: 1.35-29.72 and 6.26; 95% CI: 1.02-38.35 respectively). CONCLUSION In this cohort of Russian TB patients, substance abuse was a strong predictor of non-adherence and default. DOTS programmes may benefit from incorporating measures to diagnose and treat alcohol misuse within the medical management of patients undergoing TB therapy. Multidrug-resistant TB occurred among adherent patients who had been hospitalized in the course of their therapy. This raises the possibility that treatment for drug-sensitive disease unmasked a pre-existing population of drug-resistant organisms, or that these patients were reinfected with a drug-resistant strain of TB.

Treating multidrug-resistant tuberculosis in Tomsk, Russia: developing programs that address the linkage between poverty and disease.

Tuberculosis (TB) and multidrug‐resistant TB (MDR‐TB) are diseases of poverty. Because Mycobacterium tuberculosis exists predominantly in a social space often defined by poverty and its comorbidities—overcrowded or congregate living conditions, substance dependence or abuse, and lack of access to proper health services, to name a few—the biology of this organism and of TB drug resistance is intimately linked to the social world in which patients live. This association is demonstrated in Russia, where political changes in the 1990s resulted in increased socioeconomic inequality and a breakdown in health services. The effect on TB and MDR‐TB is reflected both in terms of a rise in TB and MDR‐TB incidence and increased morbidity and mortality associated with the disease. We present the case example of Tomsk Oblast to delineate how poverty contributed to a growing MDR‐TB epidemic and increasing socioeconomic barriers to successful care, even when available. The MDR‐TB pilot project implemented in Tomsk addressed both programmatic and socioeconomic factors associated with unfavorable outcomes. The result has been a strengthening of the overall TB control program in the region and improved case‐holding for the most vulnerable patients. The model of MDR‐TB care in Tomsk is applicable for other resource‐poor settings facing challenges to TB and MDR‐TB control.

Development of Extensively Drug-resistant Tuberculosis during Multidrug-resistant Tuberculosis Treatment

RATIONALE Extensively drug-resistant (XDR) tuberculosis (TB) may arise in individuals on treatment for multidrug-resistant (MDR) TB. Preventing this amplification of resistance will likely improve clinical outcomes and delay the secondary spread of XDR-TB. OBJECTIVES To measure the proportion of individuals that develops XDR-TB during the course of MDR-TB treatment, and to identify those factors associated with the development of XDR. METHODS We performed a retrospective analysis of 608 consecutive patients with documented MDR-TB who were started on MDR-TB treatment between September 10, 2000 and November 1, 2004 in the Tomsk Oblast TB Treatment Services in Western Siberia, Russian Federation. MEASUREMENTS AND MAIN RESULTS A total of 6% of patients were observed to develop XDR-TB while on MDR-TB treatment. These patients were significantly less likely to be cured or to complete treatment. Using Cox proportional hazard models, we found that the presence of bilateral and cavitary lesions was associated with a greater than threefold increase in hazard (adjusted hazard ratio [HR], 3.47; 95% confidence interval [CI], 1.32-9.14). Prior exposure to a second-line injectable antibiotic was associated with a greater than threefold increase in hazard (adjusted HR, 3.65; 95% CI, 1.81-7.37), and each additional month in which a patient failed to take at least 80% of their prescribed drugs was associated with nearly an additional 20% hazard of developing XDR-TB (adjusted HR, 1.17; 95% CI, 1.01-1.35). CONCLUSIONS Early and rapid diagnosis, timely initiation of appropriate therapy, and programmatic efforts to optimize treatment adherence during MDR-TB therapy are crucial to avoiding the generation of excess XDR-TB in MDR-TB treatment programs.

Improving Outcomes for Multidrug-Resistant Tuberculosis: Aggressive Regimens Prevent Treatment Failure and Death

BACKGROUND Evidence is sparse regarding the optimal construction of regimens to treat multidrug-resistant (MDR) tuberculosis disease due to strains of Mycobacterium tuberculosis resistant to at least both isoniazid and rifampin. Given the low potency of many second-line antituberculous drugs, we hypothesized that an aggressive regimen of at least 5 likely effective drugs during the intensive phase, including a fluoroquinolone and a parenteral agent, would be associated with a reduced risk of death or treatment failure. METHODS We conducted a retrospective cohort study of patients initiating MDR tuberculosis treatment between 2000 and 2004 in Tomsk, Russian Federation. We used a multivariate Cox proportional hazards model to assess whether monthly exposure to an aggressive regimen was associated with the risk of death or treatment failure. RESULTS Six hundred fourteen individuals with confirmed MDR tuberculosis were eligible for analysis. On multivariable analysis that adjusted for extensively drug-resistant (XDR) tuberculosis-MDR tuberculosis isolates resistant to fluoroquinolones and parenteral agents-we found that monthly exposure to an aggressive regimen was significantly associated with a lower risk of death or treatment failure (hazard ratio, 0.52 [95% confidence interval, .29-.94]; P = .030). CONCLUSIONS Receipt of an aggressive treatment regimen was a robust predictor of decreased risk of death or failure during MDR tuberculosis treatment. These findings further support the use of this regimen definition as the benchmark for the standard of care of MDR tuberculosis patients and should be used as the basis for evaluating novel therapies.

Hepatotoxicity during treatment for multidrug-resistant tuberculosis: occurrence, management and outcome.

SETTING Multidrug-resistant tuberculosis (MDR-TB) treatment program in Tomsk, Russia. OBJECTIVE To describe the incidence and management of hepatotoxicity during treatment of MDR-TB, and to assess risk factors associated with its development and impact on treatment outcomes. DESIGN A retrospective case series performed among 608 patients. RESULTS Hepatotoxicity, using American Thoracic Society (2006) definitions, was observed in 91/568 patients (16.5%). The median time to the first hepatotoxic event was 196 days post treatment commencement. Baseline factors associated with hepatotoxicity included elevated alanine aminotransferase/aspartate aminotransferase/bilirubin (OR 53.9, 95%CI 6.30-438.7), and renal insufficiency (OR 19.6, 95%CI 2.71-141.6). High treatment adherence (OR 3.25, 95%CI 2.07-5.09) and starting treatment in prison (OR 1.77, 95%CI 1.04-3.01) were associated with treatment success. Smoking (OR 0.44, 95%CI 0.21-0.92) and bilateral cavitary disease (OR 0.51, 95%CI 0.34-0.77) were associated with worse outcomes. For alcohol users, developing hepatotoxicity was associated with better outcomes (OR 4.40, 95%CI 1.79-10.81) than not (OR 0.42, 95%CI 0.25-0.68). One or more medications were permanently stopped in 10/91 patients, but in no case was treatment entirely discontinued. CONCLUSION MDR-TB treatment in the face of hepatotoxicity during therapy did not result in a statistically significant increase in poor outcomes.

Multidrug-resistant tuberculosis treatment failure detection depends on monitoring interval and microbiological method

Debate persists about monitoring method (culture or smear) and interval (monthly or less frequently) during treatment for multidrug-resistant tuberculosis (MDR-TB). We analysed existing data and estimated the effect of monitoring strategies on timing of failure detection. We identified studies reporting microbiological response to MDR-TB treatment and solicited individual patient data from authors. Frailty survival models were used to estimate pooled relative risk of failure detection in the last 12 months of treatment; hazard of failure using monthly culture was the reference. Data were obtained for 5410 patients across 12 observational studies. During the last 12 months of treatment, failure detection occurred in a median of 3 months by monthly culture; failure detection was delayed by 2, 7, and 9 months relying on bimonthly culture, monthly smear and bimonthly smear, respectively. Risk (95% CI) of failure detection delay resulting from monthly smear relative to culture is 0.38 (0.34–0.42) for all patients and 0.33 (0.25–0.42) for HIV-co-infected patients. Failure detection is delayed by reducing the sensitivity and frequency of the monitoring method. Monthly monitoring of sputum cultures from patients receiving MDR-TB treatment is recommended. Expanded laboratory capacity is needed for high-quality culture, and for smear microscopy and rapid molecular tests. Monthly culture monitoring is crucial to earlier detection of treatment failure in MDR-TB patients http://ow.ly/w2MI301mK8M