A study of TB-associated immune reconstitution inflammatory syndrome using the consensus case-definition.

BACKGROUND & OBJECTIVES A considerable proportion of patients with HIV associated tuberculosis (TB) started on highly active antiretroviral therapy (HAART) develop immune reconstitution inflammatory syndrome (IRIS), which is difficult to diagnose in a resource-limited setting. In view of the recently proposed consensus case-definitions for TB-IRIS for use in resource-limited settings we undertook this study to describe the incidence and risk factors of TB associated IRIS in a tertiary care hospital and research centre in north India. METHODS Retrospective analysis of antiretroviral treatment (ART) naïve adults started on highly active ART (HAART) from June 2006 to September 2008 was done. RESULTS Of the 627 patients studied, 237 (38%) had TB at the initiation of HAART. In total, 18 (7.5%) of 237 patients with TB at baseline had paradoxical TB-associated IRIS, and 12 (3%) of 390 patients without TB at baseline developed ART-associated TB. Most IRIS events occurred during the initial 30 days of HAART. Two patients developed TB-associated IRIS after 90 days of HAART. Using univariate analysis, low CD4+ cell count at baseline [64 (28-89) vs. 95 (52-150); P=0.009] and early initiation of HAART [33 (24-41) vs. 48 (35-61) days; P<0.001] were significantly associated with paradoxical TB-associated IRIS. No identifiable risk factors were associated with the development of ART-associated TB. INTERPRETATION & CONCLUSION A considerable proportion of patients on HAART develop TB-associated IRIS. The consensus case-definition is a useful tool in resource-limited settings for the diagnosis of TB- associated IRIS.