Incidence and determinants of tuberculosis infection among adult patients with HIV attending HIV care in north-east Ethiopia: a retrospective cohort study

OBJECTIVE: This study assessed the incidence of tuberculosis (TB) and its predictors among adults living with HIV/AIDS in government health facilities in north-east Ethiopia. SETTING: A 5-year retrospective cohort study was conducted from May to June 2015 on 451 adult HIV/AIDS-infected individuals who enrolled in the HIV care clinics of government health facilities in north-east Ethiopia. PARTICIPANTS: A total of 451 HIV-infected adults who newly enrolled in the adult HIV care clinic from 1 July 2010 with complete information were followed until May 2015. PRIMARY OUTCOME MEASURE: The primary outcome was the proportion of patients diagnosed with TB or the TB incidence rate. SECONDARY OUTCOME MEASURE: The incidence of TB was investigated in relation to years of follow-up. RESULTS: A total of 451 charts with complete information were followed for 1377.41 person-years (PY) of observation. The overall incidence density of TB was 8.6 per 100 PYof observation. Previous TB disease (adjusted HR (AHR) 3.65, 95% CI 1.97 to 6.73), being bedridden (AHR 5.45, 95% CI 1.16 to 25.49), being underweight (body mass index (BMI) <18.5 kg/m(2)) (AHR 2.53, 95 % CI 1.27 to 5.05), taking isoniazid preventive therapy (IPT) (AHR 0.14, 95% CI 0.05 to 0.39), haemoglobin below 11 g/dL (AHR 2.31, 95% CI 1.35 to 3.93), and being in WHO clinical stages III and IV (AHR 2.84, 95% CI 1.11 to 7.27; AHR 3.07, 95% CI 1.08 to 8.75, respectively) were significant for the incidence of TB. CONCLUSION: The incidence of TB among adults living with HIV/AIDS in the first 3 years of follow-up was higher compared with that of subsequent years. Previous TB disease, no IPT, low BMI and haemoglobin level, advanced WHO clinical stage, and bedridden condition were the determinants of the incidence of TB. Therefore, addressing the significant predictors and improving TB/HIV collaborative activities should be strengthened in the study setting.