Antituberculosis Drugs Resistance and Treatment Outcomes Among Retreatment Patients in Guinea: A Five-Year Retrospective Cohort Study

Abstract

Tuberculosis (TB) is a global outbreak whose drug resistance is a constant threat. This study aimed at describing anti-TB drugs resistance and treatment outcomes among retreatment TB patients in Guinea between 2008 and 2012. We conducted a retrospective cohort study with a sample of 558 patients aged of at least 10, who were admitted for TB retreatment and who were tested for anti-TB drugs susceptibility during the study period. Overall, 3187 retreatment TB patients were recorded from January 1, 2008 to December 31, 2012 in Guinea, of which 558 (17.5%) performed susceptibility testing to anti-TB drugs. We found overall resistance in 417 cases (74.7%) including 356 (85.4%) of multidrug resistance (MDR), 29 (6.9%) of monoresistance (isoniazid 2.9%, streptomycin 2.9%, rifampicin 0.9%, ethambutol 0.2%) and 32 (7.7% of polydrug resistance (isoniazid + streptomycin 4.3%, rifampicin + streptomycin 1.4%, isoniazid + ethambutol + streptomycin 1.0%, rifampicin + ethambutol + streptomycin 1.0%). Most of the patients (84.6%) with anti-TB drugs resistance were under 45 and labourers were mostly represented (27.8%) including drivers in majority (37.9%). MDR-TB incidence rate increased by 12.2% between 2008 (65.6%) and 2012 (77.8%), and the annual cure rate decreased gradually from 60.0% in 2009 to 45.7% in 2012. Among MDR-TB patients (n= 356), only 112 (31.5%) benefited from second-line treatment regimen, of which, 51.7% were cured, 6.3% completed treatment, 24.1% died, 6.3% were lost to follow-up and 11.6% were not evaluated. The cure rate was higher in HIV-negative patients (55.3%) than in those who were HIV-positive (35.3%) and the death rate was the highest (41.2%) in HIV-positive patients. Overall, treatment success rate was 58.0%. This study revealed a low rate of performing drug susceptibility testing, the gradual increase of the incidence of MDR-TB each year and the gradual decrease of cure rate from year to year. Besides, anti-TB drugs resistance concerned mostly drivers in our context. Prospective studies are needed for a deep understanding of the factors associated with these persistent challenges.