Outcomes of the Three-month Weekly Isoniazid With Rifapentine (3HP) Versus the Six-month Isoniazid Preventive Therapy (6H) Among People Newly Enrolled in HIV Care in Western Kenya

Background In trials, 3-month weekly rifapentine and isoniazid (3HP) showed higher adherence and completion than the 6-month daily isoniazid (6H) regimen for TB preventive treatment (TPT). However, programmatic outcome data remain limited. Methods We evaluated the TPT cascade among people with HIV (PWH) aged ≥15 years newly enrolled in HIV care in western Kenya. Initiation and completion of 6H (Jan–Sept 2022) were compared to 3HP (Oct 2022–Sept 2023) using χ2 tests. Correlates of noninitiation and noncompletion were assessed using Poisson regression with generalized linear models. Mortality within 24 months was evaluated using Cox proportional hazards regression. Results Of 1930 PWH (median age 33 years [IQR=27–41]), 65.8% were female, and 19.5% had advanced HIV disease (AHD) at enrollment. Overall, 1922 (99.6%) were screened for active TB, of whom 1790 (97.5%) were TPT-eligible; 1577 (88.1%) of these initiated TPT. TPT initiation was higher with 3HP than 6H (89.8% vs 84.2%; P < .001). TPT completion was similar for 3HP and 6H (89.2% vs 88.8% P = .77). TB incidence (per 1000 person-months) was lower among TPT-completers (0.22; 95% CI 0.15–0.35) than those who neither initiated (4.25; 95% CI 1.77–10.23) nor completed TPT (3.75; 95% CI 2.49–5.64). AHD was associated with higher risk of TPT noninitiation (aRR = 2.14; 95% CI 1.59–2.87) and noncompletion of both 6H (aRR = 2.56; 95% CI: 1.55–4.23) and 3HP (aRR = 1.68; 95% CI 1.07–2.63). Conclusions TPT initiation was significantly higher after 3HP implementation. However, 3HP completion was similar to 6H. Targeted interventions are needed to support 3HP completion, particularly in PWH with AHD.