Abstract
Background: Tuberculosis preventive therapy (TPT) among HIV-infected patients are not well established in Thailand and may be due to multifactorial reasons. One of the most crucial reasons is because most physicians are convinced that antiretroviral therapy (ART) alone can decrease the incidence rate of active tuberculosis (TB) to the incidence rate of the general population. However, the incidence of TB data among Thai HIV-infected patients on ART is also scant. This information is very important because HIV-infected patients can have latent tuberculosis infection (LTBI) which can later progress to active TB. Therefore, TPT is crucial among HIV-infected patients to prevent active TB. Method: We conducted a cross-sectional, multi-center study in HIV-infected patients from 14 hospitals throughout Thailand between 2009 and 2018. This study compared the incidence of active TB among HIV-infected patients with different CD4 cell count after ART has been initiated. Results: A total of 9,179 HIV-infected patients were enrolled; 442 (4.8%) were diagnosed with active TB after ART was initiated and 8,738 had HIV mono-infection. According to the multivariate analysis, the significant risk factors associated with active TB post ART initiation were the male sex, CD4 less than 350, body weight less than 50 kg and have a prior history of active TB. When ART was initiated at low CD4 cell count, the incidence of active TB was high (Table) compared to the general population (about 150-200 per 100,000 persons-year). Furthermore, when ART was started when the CD4 count was more than 500, the incidence rate of active TB was 2-3 times higher than the general population (394 per 100,000 persons-year). The incidence of TB for the first 2-5 years after ART was initiated decreased to 7,251, 4,083, 2,661 and 1,957 per 100,000 persons-year, respectively. However, these numbers were much higher than the general population in Thailand even when these patients were on ART for many years. Conclusions: The incidence of TB among HIV-infected patients with various CD4 cell count and on ART were high. The incidence of active TB was 2.5 times higher than the general population even when ART was initiated when CD4 was more than 500. For this reason, HIV-infected patients who have had TB infection should benefit from TPT which can decrease the incidence and mortality rate of TB.
