Background Multidrug-resistant tuberculosis (MDR-TB) is a possible threat to global tuberculosis control. Despite a disease prevalence of 263/100 000 population Pakistan lacks information on prevalence of drug resistant TB.

Objective Our objective was to estimate prevalence of MDR and associated risk factors in patients with Pulmonary Tuberculosis in Karachi.

Methods 640 adult consenting patients were enrolled from field clinics (July 2006 to August 2008) through passive case finding. Prevalence of MDR-TB with 95% CI was calculated with Epi-Info. Logistic Regression analyses were performed for risk factors associated with MDR.

Results Overall MDR rate was 5.0%, 95% CI 3.3% to 6.6% (untreated 2.3%, treated 17.9%). Mean age was 32.5 (±15.6) years. With 45.6% (n=292) females and 54.4% (n=348) males. Factors independently associated with MDR were; female gender (OR 3.12; 95% CI 1.40 to 6.91), and prior history of incomplete treatment (OR 10.1; 95% CI 4.71 to 21.64). Ethnic groups at higher risk for MDR included Sindhis (OR 4.5; 95% CI 1.42 to 14.71) and Pashtoons (OR 3.6, 95% CI 1.12 to 11.62).

Conclusion This study reports an over all MDR rate of 5.0% in our study population. It further highlights the need for MDR prevention through re-focusing DOTS delivery with emphasis on women and certain high risk sub groups.