Objective: To determine cost functions that describe the dynamics of costs of HIV treatment and care in Ghana by CD4 cell count at treatment initiation and over time on antiretroviral therapy (ART).
Design: We used detailed longitudinal healthcare utilization data from clinical health records of HIV-infected patients at seven Ghanaian ART clinics to estimate cost functions of treatment and care by CD4 cell count at treatment initiation and time on ART.
Methods: We developed two linear regression models; one with individual random effects to determine the relationship between CD4 cell count at ART initiation and costs of treatment and care, and one with individual fixed effects to determine the causal effect of time in care on costs of treatment and care.
Results: Costs for treatment and care were lowest (-7.9 US$) for patients with CD4 cell counts of at least 350 cells/μl at ART initiation, compared with patients with 50 cells/μl or less at ART initiation, yet the difference was not significant. The per-patient costs peaked during the first 6 months on ART at 112.6 US$, and significantly decreased by 70% after 4 years on treatment.
Conclusion: Our findings show that an accurate analysis of resource needs of HIV treatment and care should take into account that healthcare costs for HIV-infected people are dynamic rather than constant. The cost functions derived from our study are valuable input for cost-effectiveness analyses and research allocation exercises for HIV treatment in sub-Saharan Africa.