Predictors of treatment outcome in multidrug-resistant tuberculosis in Portugal

Predictors of treatment outcome in multidrug-resistant tuberculosis in PortugalTo the Editor:Despite progress in tuberculosis (TB) control, the response to the multidrug-resistant (MDR) TB and extensively drug-resistant (XDR) TB epidemic continues to be limited.The proportion of MDR-TB patients who successfully completed treatment varied from 44% (Eastern Mediterranean Region) to 58% (South-East Asia Region) [1].Overall, treatment success was 48%, while 28% of cases were reported as lost to follow-up or had no outcome information [1].The Global Plan's target for 2015 of achieving at least 75% treatment success in MDR-TB patients was only reached by 30 out of 107 countries [1].In the present paper, we evaluated the treatment outcomes of M/XDR-TB patients in Portugal.Patients with pulmonary TB resistant to isoniazid and rifampin, who started treatment at some point between January 2000 and December 2008, were selected from the national database, which integrates the data from the mandatory registration of TB cases.The evaluation of treatment outcomes was conducted from February to April 2011.Patients were classified as having received no previous treatment for TB or as having received previous treatment(s) for TB.The World Health Organization (WHO) standard definitions were used to MDR-TB, XDR-TB and treatment outcome (treatment success, died, failure, default and transferred out) [1,2].Was analysed the relationship between treatment outcome and clinical and demographic factors.It were also identified the predictors of poor outcome in a population of M/XDR-TB patients.The association between explanatory variables and treatment outcome was evaluated by logistic regression models.The crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were determined.We assessed MDR-TB treatment outcomes in 364 patients (257 with MDR-TB and 107 with XDR-TB), while 11 (3%) patients had no recorded final outcome (transferred out).The median age of the patients was 40 years (range: 13-86) and 259 (71.2%) patients were male.The amount of the patients that were HIVpositive was 108 (30.5%).The proportion of cases resistant to all first-line anti-TB drugs was 19.2%.Results of drug susceptibility testing (DST) to second-line drugs (amikacin, kanamycin, capreomycin, ofloxacin, ciprofloxacin, cycloserine, ethionamide, para-aminosalycilic acid, thiacetazone) were analysed.Patients with MDR-TB had a median resistance to four drugs (with a range of 2-10) and those with XDR-TB had a median resistance to eight drugs (with a range 4-10) (p,0.001).The assessment of treatment outcomes revealed that 42 (11.5%)patients were cured, 184 (50.5%) completed treatment, 92 (25.3%) died, 21 (5.8%) experienced treatment failure, and 25 (6.9%) defaulted treatment.Thus, 226 (62.1%) patients achieved a successful outcome.The treatment success rate was significantly different for patients who were never treated for TB and for patients who received previous TB treatment (68% versus 54%; p50.01), and between patients with MDR-TB and XDR-TB (66% versus 52%; p50.018).Univariate analysis indicated that treatment outcome was significantly associated with injection drug use only (OR 3.34, 95% CI 1.53-7.31;p50.003), alcohol abuse and injection drug use (OR 10.56, 95% CI 1.21-92.25;p50.033),HIV-positive status (OR 3.38, 95% CI 2.11-5.42;p,0.001), previous TB treatment (OR 1.76, 95% CI 1.25-2.70;p50.010), resistance to kanamycin alone (OR 1.89, 95% CI 1.20-2.99;p50.006), and XDR-TB (OR 1.78, 95% CI 1.13-2.82;p50.014) (table 1).