Treatment outcomes and survival based on drug resistance patterns in multidrug-resistant tuberculosis.
BACKGROUND
Few large-scale studies have investigated multidrug-resistant tuberculosis (MDR-TB) treatment outcomes relative to drug-resistance patterns.


OBJECTIVE
To assess the impact of additional drug resistances on treatment outcomes and long-term survival in a large HIV-negative MDR-TB cohort.


METHODS
Treatment outcomes and long-term survival of patients with MDR-TB newly diagnosed or retreated in 2000 to 2002 were retrospectively analyzed based on drug-resistance patterns after 5-8 years of follow-up.


RESULTS
Of 1,407 patients with MDR-TB, 75 (5.3%) had extensively drug-resistant TB (XDR-TB(re)) by the revised definition; 159 (11.3%) had ofloxacin-resistant pre-XDR-TB (pre-XDR-TB(o)); and 117 (8.3%) had second-line injectable drug (SLID)-resistant pre-XDR-TB (pre-XDR-TB(s)). Patients with XDR-TB(re) showed the lowest treatment success rate (29.3%) and the poorest long-term survival, and XDR-TB(re) was more strongly associated with long-term mortality than XDR-TB as originally defined (hazards ratio [HR], 3.15; 95% confidence interval [CI], 2.06-4.83; P < 0.001 vs. HR, 2.15; 95% CI, 1.49-3.09; P < 0.001). Patients with either form of pre-XDR-TB showed poorer cumulative survival than those with ofloxacin-susceptible/SLID-susceptible MDR-TB (P < 0.05 for each comparison). Although streptomycin susceptibility did not affect the treatment outcomes of patients with pre-XDR-TB, streptomycin-resistant pre-XDR-TB was more strongly associated with long-term mortality than ofloxacin-susceptible/SLID-susceptible MDR-TB (HR, 2.17; 95% CI, 1.22-3.84; P < 0.008 for pre-XDR-TB(o); and HR, 2.69; 95% CI, 1.40-5.16; P = 0.003 for pre-XDR-TB(s)).


CONCLUSIONS
The revised XDR-TB definition is appropriate for defining patients with MDR-TB with the poorest outcomes. Both pre-XDR-TB(o) and pre-XDR-TB(s) were independently associated with poor long-term survival in patients with MDR-TB. SM susceptibility was linked to better survival in patients with pre-XDR-TB.
Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Dankook University College of Medicine, Dankook University Hospital,Cheonan, South Korea.
Doh Hyung
DH
Kim
Hee Jin
HJ
Kim
Seung-Kyu
SK
Park
Suck-Jun
SJ
Kong
Young Sam
YS
Kim
Tae-Hyung
TH
Kim
Eun Kyung
EK
Kim
Ki Man
KM
Lee
Sung-Soon
SS
Lee
Jae Seuk
JS
Park
Won-Jung
WJ
Koh
Chang-Hoon
CH
Lee
Tae Sun
TS
Shim
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000627:therapeutic use*; D054908:Extensively Drug-Resistant Tuberculosis / Q000145:classification / Q000188:drug therapy* / Q000401:mortality; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007723:Korea / Q000453:epidemiology; D008297:Male; D055118:Medication Adherence; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D012189:Retrospective Studies; D013307:Streptomycin; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000401:mortality; D055815:Young Adult
D000995:Antitubercular Agents; D024841:Fluoroquinolones; D013307:Streptomycin