Coverage of Isoniazid Preventive Therapy among people living with HIV: A retrospective cohort study in Tanzania (2012–2016)

BACKGROUND Isoniazid Preventive Therapy (IPT) is a proven public health tool to reduce Tuberculosis (TB) among people living with HIV. However, it implementation in most countries is suboptimal. This retrospective study was conducted to determine the coverage and factors associated with IPT initiation to inform program scale up and improve quality of service in Tanzania and elsewhere. METHODS Retrospective cohort study design involving HIV clinics in Dar es Salaam, Iringa and Njombe regions from January 2012 to December 2016. RESULTS A total of 171,743 PLHIV were in the cohort from 2012 to 2016. Of these, 166,709 were involved in the analysis. Of those analyzed, 23,970 (14.38%) were ever initiated on IPT. Female sex (aOR = 1.72, 95% CI: 1.13, P < 0.001), obesity (aOR = 1.29, 95% CI:1.20-1.39, P < 0.001), WHO clinical stage II (aOR = 1.48, 95% CI: 1.42-1.55, P < 0.001), enrolment in hospitals (aOR = 1.98, 95% CI: 1.89-2.06, P < 0.001), enrolment in Njombe region (aOR = 1.25: 95% CI: 1.18-1.33, P < 0.001) and enrolment in public health facilities (aOR = 1.93: 95% CI: 1.82-2.04, P < 0.001) were associated with increased IPT uptake. Being on ART (aOR = 0.67, 95% CI: 0.65-0.70, P < 0.001) and severe nutritional status (aOR = 0.72, 95% CI: 0.60-0.88, P < 0.001) were associated with decreased IPT initiation. CONCLUSIONS Our study documented low IPT initiation in the study area as well as documented factors which enable IPT initiation and those which impair IPT initiation. Strategies are needed to work on barriers and sustain enabling factors to improve IPT coverage.