Prevalence of multidrug-resistant tuberculosis among newly diagnosed cases of sputum-positive pulmonary tuberculosis.

Background & objectives: The prevalence of multidrug-resistant tuberculosis (MDR-TB) is increasing throughout the world. Although previous treatment for TB is the most important risk factor for development of MDR-TB, treatment-naïve patients are also at risk due to either spontaneous mutations or transmission of drug-resistant strains. We sought to ascertain the prevalence of MDR-TB among new cases of sputum-positive pulmonary TB. Methods: This was a prospective, observational study involving newly diagnosed cases of sputum-positive pulmonary tuberculosis diagnosed between 2008 and 2009 carried out in New Delhi, India. All sputum-positive TB cases were subjected to mycobacterial culture and first-line drug-susceptibility testing (DST). MDR-TB was defined as TB caused by bacilli showing resistance to at least isoniazid and rifampicin. Results: A total of 218 cases of sputum-positive pulmonary tuberculosis were enrolled between 2008 and 2009. Of these, 41 cases had negative mycobacterial cultures and DST was carried out in 177 cases. The mean age of the patients was 27.8 ± 10.2 yr; 59 patients (27%) were female. All patients tested negative for HIV infection. Out of 177 cases, two cases of MDR-TB were detected. Thus, the prevalence of MDR-TB among newly diagnosed pulmonary tuberculosis patients was 1.1 per cent. Interpretation & conclusions: MDR-TB prevalence is low among new cases of sputum-positive pulmonary TB treated at primary care level in Delhi. Nation-wide and State-wide representative data on prevalence of MDR-TB are lacking. Efforts should be directed towards continued surveillance for MDR-TB among newly diagnosed TB cases.

Evaluation of risk factors for antituberculosis treatment induced hepatotoxicity.

Background & objectives: Antituberculosis (anti-TB) drug induced hepatotoxicity (DIH) is the most common side effect leading to interruption of therapy. Wide variations have been found in the reported incidence of hepatotoxicity during short-course chemotherapy. Several risk factors for hepatotoxicity have been suggested in previous studies. We undertook a prospective case-control study to assess the role of these putative risk factors in the development of DIH in patients receiving anti-TB treatment. Methods: One hundred and seventy five consecutive cases with a diagnosis of anti-TB DIH were compared with 428 consecutive controls who took anti-TB drugs for the full duration of chemotherapy without clinical or biochemical evidence of hepatitis. Cases positive for markers of acute viral hepatitis were carefully excluded. Cases and controls were compared with respect to age, sex, site of tuberculosis, radiological extent of disease on chest radiograph, body mass index (BMI), mid-arm circumference (MAC) and liver function at baseline which included serum bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), serum total protein and serum albumin. Results: Univariate logistic regression revealed that the risk of developing DIH was greater in older patients. Significantly greater percentage of cases had extrapulmonary tuberculosis (TB) (P<0.01). Also, a significantly higher percentage of cases had moderate to far advanced disease severity on chest radiograph (P<0.01). On multivariate logistic regression, the adjusted odds were significant (P<0.01) for age >35 yr, MAC <20 cm and hypoalbuminaemia (albumin <3.5 g/dl). Interpretation & conclusions: Older age, poor nutritional status including baseline hypoalbuminaemia were independent predictors of occurrence of anti-TB DIH. Clinicians should be vigilant for occurrence of hepatotoxicity in this high risk group.