PURPOSE: To study the treatment outcomes of MDR-TB and XDR-TB and their associated factors.
METHODS: All consecutive MDR-TB cases treated under programmatic setting in Hong Kong from 1997 through 2006 were enrolled retrospectively, with case categories and clinical outcomes classified according to Laserson’s criteria, and followed up until December 2009.
RESULTS: Of 279 MDR-TB patients, 30 (10.7%) had XDR-TB. After excluding 9 patients who died before receiving second-line drugs for treatment, among the remaining 270 patients, 187 (69.3%) achieved treatment success (cure or treatment completion), 26 (9.6%) died , 45 (16.7%) defaulted, 9 (3.3%) transferred out, and 3 (1.1%) failed.Eleven (40.7%) XDR-TB patients versus 176 (72.4%) non-XDR MDR-TB patients had successful outcome (P=0.003). On multivariate analysis, independent predictors for treatment success were use of 4 or more effective drugs: OR 2.42 (95%CI 1.21-4.83), and less advanced disease on CXR: OR 2.38 (1.01-5.58). XDR-TB patients also had higher overall mortality (50.0% versus 25.7%, P=0.018), and TB-related mortality (33.3% versus 4.41%, P=0.001) than patients with non-XDR MDR-TB. Eight out of 187 successfully treated patients had relapse on follow-up. XDR-TB was the only predictor for relapse: OR 6.80 (1.25-37.19). The 176 non-XDR MDR-TB patients who achieved treatment success had antituberculosis drugs for 15.7 +/- 3.6 (mean +/- SD) months. Sputum culture conversion at 3 months or less, and non-cavitary disease on CXR were significantly associated with a treatment duration of 15 months or less (all P< 0.05). No significant difference in relapse rates (0.50 versus 0.74 per 100 person-years, P=0.68) was found between patients who had 15 months or less and those who had longer treatment.
CONCLUSION: XDR-TB patients had worse prognosis than those with non-XDR MDR-TB. Treatment duration of 15 months or less might be sufficient for some MDR-TB patients.
CLINICAL IMPLICATIONS: Randomized trials should be considered to determine the optimal duration of treatment of MDR-TB without extensive drug resistance.
DISCLOSURE: Wing Yew, Other Wing Wai Yew has received indirect sponsorship from GlaxoSmithKline and Pfizer to participate in international conferences; No Product/Research Disclosure Information