Year: 2025 | Month: July | Volume: 15 | Issue: 7 | Pages: 203-214
DOI: https://doi.org/10.52403/ijhsr.20250725
Survival of Individuals on Long-Acting Cabotegravir Injection for HIV Pre-Exposure Prophylaxis in Zambia: A Retrospective Cohort Study
Lackeby Kawanga1,3, Eustarkio Kazonga1,2, Bryson Musonda1, Innocent Mwaba1, Adamson Ndhlovu1, Paul Kasinde1, Norah Ndambo1, Mangani Thanthwe1, Andrew Phiri1, Vincent Kapungu1
1School of Postgraduate Studies, University of Lusaka, Lusaka, Zambia
2Department of Public Health, School of Medicine and Health Sciences, University of Zambia, Zambia.
3JSI Research and Training Institute
Corresponding Author: Lackeby Kawanga
ABSTRACT
Background: The HIV epidemic continues to pose a public health challenge in Zambia, despite advances in prevention strategies such as pre-exposure prophylaxis (PrEP). While oral PrEP is effective, daily drug administration remains a significant barrier. Long-acting cabotegravir (CAB LA), an injectable PrEP alternative, addresses this adherence challenge through reduced dosing frequency. This study aimed to assess the survival of individuals on CAB LA for PrEP and identify determinants associated with CAB LA discontinuation.
Methods: A retrospective cohort study was conducted using secondary data from the Electronic Health Record on individuals initiating CAB LA between February and September 2024 in Chibombo and Kitwe districts, Zambia. Survival analysis methods, including Kaplan-Meier estimates and Cox proportional hazards regression, were employed to determine survival probabilities and factors associated with discontinuation over a 10-month period. Survival rates between individuals with and without prior oral PrEP exposure were also compared.
Results: The survival analysis involved 1,308 individuals contributing 6,386 person-months of follow-up and recorded 823 discontinuations. The median survival time was seven months, with a discontinuation incidence rate of 0.129 per person-month. Survival probabilities decreased over time: 81.6% at one month, 66.6% at three months, 50.6% at five months, 35.5% at seven months, and 26.4% at nine months. Oral PrEP-experienced individuals had a 33% lower hazard of discontinuation, while males had a 20% higher hazard than females. Older age modestly reduced discontinuation risk.
Conclusion: CAB LA demonstrates varying survival probabilities over time, with significant predictors of discontinuation identified. These findings underscore the importance of tailored interventions to improve adherence, particularly for males and PrEP-naïve individuals.
Key words: HIV prevention, Pre-exposure prophylaxis (PrEP), Long-acting cabotegravir (CAB LA), Discontinuation, Survival analysis.