Isoniazid preventive therapy use among patients on antiretroviral therapy: a missed opportunity.

Isoniazid preventive therapy (IPT) with antiretroviral therapy (ART) reduces incident tuberculosis among patients infected with the human immunodeficiency virus. We describe IPT use among patients on ART at two primary care clinics in South Africa. Of 597 participants interviewed, 100 (16.8%) reported IPT use; 73.4% (365/497) with no reported IPT use were eligible for IPT. IPT use was associated with age <35 years (aOR 1.90, 95%CI 1.18-3.06), and receiving care at one clinic as opposed to the other (aOR 4.72, 95%CI 2.69-7.93). The high proportion of patients on ART eligible for IPT represents a missed opportunity for IPT scale-up.