Epidemiology of extrapulmonary and disseminated tuberculosis in a tertiary care center in Oman

The incidence of extrapulmonary and disseminated tuberculosis (TB) cases is increasing worldwide, and this growth significantly impacts TB-related morbidity and mortality. Little is known about the host risk factors for extrapulmonary and disseminated TB. In this study, we examined those risk factors.

We conducted a retrospective review of all TB cases admitted to Sultan Qaboos University Hospital from 2006 to 2015. We compared extrapulmonary TB (EPTB) cases with pulmonary and disseminated TB cases. We evaluated the risk factors associated with the development of extrapulmonary and disseminated TB using logistic regression analysis.

We reviewed 260 TB cases, of which EPTB comprised 37%, PTB comprised 53%, and disseminated TB comprised 10%. The most common sites of infection in the EPTB group were the lymph nodes and the abdomen. Disseminated TB and TB meningitis were more common in expatriates than in Omanis. Patients with EPTB were less likely to smoke compared to a patient with PTB. Patients with disseminated TB had a higher mortality when compared to patients with EPTB (adjusted odds ratio [OR], 0.004; 95% confidence intervals [CI]: 0.001-0.054;P = 0.001) and PTB (adjusted OR, 0.022; 95% CI: 0.004-0.115;P = 0.001). Human immunodeficiency virus (HIV) was the main risk factor for patients with disseminated TB when compared to patients with extrapulmonary and PTB.

The rates of extrapulmonary and disseminated TB in Oman are higher than what has been recognized. Expatriates, patients with HIV, and smokers are at high risk for disseminated TB. In these patients, suspected extrapulmonary sites should be evaluated and sampled to exclude disseminated TB.