There were 333 patients (27%) with prevalent TB at baseline. Among these patients a median of 99 days (IQR: 62-155 days) of ATT had been completed prior to the initiation of ART. There were nine cases of multi-drug resistant (MDR) TB among the prevalent TB cases (3%). 10 patients on ATT were transferred to other facilities and another 10 patients became lost to follow up prior to completing 3 months of ART. These 20 patients were excluded from further analysis.
Of the 313 prevalent TB cases included, 6 were found to be responding poorly to ATT prior to ART initiation. 54 of the remaining 307 patients had a clinical deterioration during the first three months of ART initiation and were suspected by clinicians to have TB IRIS. Among these, 12 had other medical issues as a cause for their clinical deterioration. Of the remaining 42 possible TB IRIS cases 7 presented with only 1 minor criterion, thereby not fulfilling the INSHI case definition (). These cases consisted of 4 patients with isolated constitutional symptoms, 2 with worsening cough and one with worsening hepatomegaly.
According to the INSHI case definition the proportion of patients with TB IRIS was 11% (35 out of 313 patients). These patients presented with symptoms at a median of 18 days (IQR 14-28 days) after ART initiation. The majority had at least one major criterion (n=24, 68%) and a smaller proportion (n=11, 32%) were diagnosed by fulfilling at least 2 minor criteria.
In the bivariate analysis, the only variable found to be significantly associated with the development of TB IRIS in this cohort was a low pre-ART CD4 count (). TB IRIS occurred in 19% of patients with a CD4 count of less than 50 cells/mm3, in 10% of those with a CD4 count between 50 and 100 cells/mm3, and in 5.4% of patients with CD4 counts greater than100 cells/mm3. Extrapulmonary TB (EPTB) was not found to be significantly associated with TB IRIS in this cohort.
Characteristics of TB/HIV co-infected patients with and without paradoxical TB-associated IRIS
Mortality among TB IRIS cases was low, with one possible associated death (2%). This occurred in a patient diagnosed with smear positive pulmonary TB who commenced ART 7 days after the initiation of ATT. She presented 13 days after ART initiation with marked respiratory symptoms and worsening pulmonary infiltrates and died in hospital 27 days later. ATT drug resistance results were not available and oral corticosteroids were administered in this case. No autopsy was performed.
19 patients (54%) with TB IRIS required either hospitalisation and/or the administration of oral corticosteroids during the episode. 8 (23%) patients were hospitalised and 13 (37%) received oral corticosteroid therapy. Symptoms among the 7 patients who were not included in the IRIS case definition due to insufficient criteria resolved spontaneously.