Abstract:

Objective To analyze the relationship between bacterial load and treatment failure and recurrence of sputum positive retreatment pulmonary tuberculosis patients, providing reference for the diagnosis and treatment of retreatment tuberculosis. Methods A retrospective cohort study including 400 patients of sputum positive retreatment pulmonary tuberculosis except multidrug-resistant and extensive drug-resistant in 22 tuberculosis designated institutions from July 2009 to July 2012 were conducted. New treatment regimen and standard treatment regimen for retreatment tuberculosis patients were adopted. All patients with successful treatment were followed up to July 2019 (a total of 7 years). Fifty-one cases of retreatment failure were selected as failure group and 23 cases of recurrence after successful treatment were selected as recurrence group. Clinical data between failure group and recurrence group were analyzed. Results The previous dosage of rifampicin drugs (low dosage 70.2% (33/47) and 52.2% (12/23), normal dosage 29.8% (14/47) and 47.8% (11/23)), retreatment types (recurrence 51.0% (26/51) and 56.6% (13/23), initial treatment failure 23.5% (12/51) and 21.7% (5/23), other retreatment 25.5% (13/51) and 21.7% (5/23)), drug susceptibility test result before treatment (sensitive 34.0% (17/50) and 31.8% (7/22), isoniazid resistance 32.0% (16/50) and 31.8% (7/22), rifampicin resistance 12.0% (6/50) and 13.7% (3/22), other drugs resistance 22.0% (11/50) and 22.7% (5/22)), previous accumulated treatment duration (<6 month 24.0% (12/50) and 21.7% (5/23), ≥6 month 76.0% (38/50) and 78.3% (18/23)) and the number of retreatment (1 time 78.4% (40/51) and 87.0% (20/23), ≥2 times 21.6% (11/51) and 13.0% (3/23)) were all compared between failure and recurrence group and there were no statistical significance (χ²=2.189,P=0.139;χ²=0.206,P=0.902;Fisher exact probability test,P>0.999;χ²=0.045,P=0.832;χ²=0.298,P=0.585). The proportions of Mycobacterium tuberculosis load >2+ in sputum smear testing and culture testing before treatment in failure group (44.9% (22/49) and 63.9% (23/36)) were higher than in recurrence group (8.7% (2/23) and 12.5% (2/16)) and the differences between the two groups were statistically significant (χ² values were 9.232 and 11.718,P values were 0.002 and 0.001) respectively. Conclusion The failure rate of sputum positive retreatment pulmonary tuberculosis patients with high bacterial load was higher than the recurrence rate, and it should be paid more attention when designing the new retreatment regimen.

Key words: Tuberculosis, pulmonary, Retreatment, Mycobacterium tuberculosis, Sputum, Treatment failure, Recurrence