Latent Tuberculosis Infection and Isoniazid Preventive Therapy among Human Immunodeficiency Virus positive adults in Southern Nigeria

Aim/objectives: It was aimed to assess the prevalence of latent TB among HIV+ patients, evaluate the coverage of isoniazid preventive therapy (IPT), the  continuous risk of latent tuberculosis infection, and factors associated with the presence of latent Tb in HIV+ patients. 
Methods: This is an analytical cross-sectional study of HIV+ patients attending the HIV clinic or admitted not previously treated for TB and did not have  clinical and laboratory evidence of active TB and matched HIV-negative population attending our GOC. Data collected with a pre-tested investigator  administered questionnaire included the age, sex, height and weight, medical and drug history, and relevant physical examination findings such as body  temperature and respiratory rate. Active TB was excluded by history, sputum AFB Z-N staining, or GeneXpert test and chest radiography. Whole blood  samples were collected from participants for QuantiFERON TB Gold Plus for quantification of Interferon Gamma Release assay (IGRA) in order to  diagnose or exclude latent TB. Data were analyzed using IBM SPSS version 25.0 software at a level of significance of p < 0.05. Association between means  and qualitative variables was analyzed with student-t-test and Chi-square test 
Results: The mean ages of the HIV+ and control groups were 42.69 ± 9.91 and 41.29 ± 9.20 years respectively with no significant statistical difference.  76(95.0%) of HIV+ patients and 74(92.5%) controls had no symptoms of TB and chronic lung disease. 18(22.5%) HIV+ patients and 2(2.5%) controls were  exposed to persons with chronic cough (p=<0.001). The prevalence of latent TB among HIV+ patients was 22.50% and 10.0% among controls (p-  value=0.001). 8(44.4%) out of 18 with latent TB had prior use of IPT compared with 24 (38.7%) out of 62 without latent TB (p-value =0.67). CD4 count was a  significant factor associated with the presence of latent TB among HIV+ persons (p-0.03). Similarly, there was a significant association between viral load  and positive IGRA (p<0.001). 
Conclusion: Latent TB infection remains significantly higher among HIV+ than HIV-negative patients which may account for the higher incidence of active  disease amongst them. Isoniazid preventive therapy coverage was poor amongst HIV+ patients in this study. 