AGE, GENDER, CLINICAL AND MICROBIOLOGICAL PECULIARITIES OF TB PATIENTS WITH EXTENSIVE DRUG RESISTANCE
We investigated factors associated with the development of extensively drug resistant (XDR) TB and treatment options. Materials and methods. We analyzed TB treatment cases in 14 regions of the Russian Federation notified in 2015 and 2016. The main group: 708 XDR TB cases. Control group 1 included 4,369 multidrug resistant (MDR) TB cases. Control group 2 included 4,320 cases with drug sensitive TB. The data were stratified by notification and gender. Results. In the main group prevailed TB cases after treatment failure (67.5% vs. 48.9% in group 1 and 5.6% in group 2; p < 0.001) due to a decreased share of new TB cases (13.4% vs. 29.7% and 77.3%, respectively) and relapses (7.2% vs. 9.8% and 10.7%). The median age of all patients was 39. The share of female patients was higher among new TB cases of the main group (37.9% vs. 28.9% and 28.1%, respectively; p < 0.05). The share of HIV-positives in the main group (15.8%) was somewhat lower than in control group 1 (19.7%; p < 0.01) but did not differ from this rate in control group 2 (16.3%; p > 0.05). The share of rural population was 31.0%, 28.5% and 31.1%, respectively, p > 0.05. The frequency of lung cavities was 73.7%, 64.9% and 59.2%, respectively, p < 0.001. The frequency of sputum positivity confirmed by microscopy was 64.7% vs. 57.5% and 56.8%, respectively, p < 0.001. The established resistance to drugs in the main group and control group 1 was as follows: ethambutol - 76.8% and 58.1%, respectively, ethionamide - 48.5% and 11.9%, cycloserine - 24.4% and 4.4%, amino-salicylic acid - 19.8% and 3.4%. Discussion. The structure of XDR TB cases confirms that treatment failure is the major risk factor for XDR TB development, while treatment interruption is not an essential risk factor. We did not establish influence of HIV-infection or place of residence on the frequency of primary or acquired XDR TB. More massive bacterioexcretion and lung cavities in XDR TB cases are associated with higher epidemic danger. Administration of ethambutol, ethionamide or protionamide is not effective for XDR TB cases. Conclusions. The treatment outcome defined as "treatment failure" is the major risk factor for XDR TB. The influence of treatment interruption, HIV-infection or place of residence on the frequency of XDR TB is not proved. The hypothesis about higher epidemic danger of XDR TB is confirmed. It is advisable to widely use collapse therapy and novel TB drugs to treat XDR TB.