The Impact of Monitoring HIV Patients Prior to Treatment in Resource-Poor Settings: Insights from Mathematical Modelling

Abstract

BackgroundThe roll-out of antiretroviral treatment (ART) in developing countries concentrates on finding patients currently in need, but over time many HIV-infected individuals will be identified who will require treatment in the future. We investigated the potential influence of alternative patient management and ART initiation strategies on the impact of ART programmes in sub-Saharan Africa.Methods and FindingsWe developed a stochastic mathematical model representing disease progression, diagnosis, clinical monitoring, and survival in a cohort of 1,000 hypothetical HIV-infected individuals in Africa. If individuals primarily enter ART programmes when symptomatic, the model predicts that only 25% will start treatment and, on average, 6 life-years will be saved per person treated. If individuals are recruited to programmes while still healthy and are frequently monitored, and CD4+ cell counts are used to help decide when to initiate ART, three times as many are expected to be treated, and average life-years saved among those treated increases to 15. The impact of programmes can be improved further by performing a second CD4+ cell count when the initial value is close to the threshold for starting treatment, maintaining high patient follow-up rates, and prioritising monitoring the oldest (≥ 35 y) and most immune-suppressed patients (CD4+ cell count ≤ 350). Initiating ART at higher CD4+ cell counts than WHO recommends leads to more life-years saved, but disproportionately more years spent on ART.ConclusionsThe overall impact of ART programmes will be limited if rates of diagnosis are low and individuals enter care too late. Frequently monitoring individuals at all stages of HIV infection and using CD4 cell count information to determine when to start treatment can maximise the impact of ART.

Higher risk of unsafe sex and impaired quality of life among patients not receiving antiretroviral therapy in Cameroon: results from the EVAL survey (ANRS 12–116)

“…Finally, in light of recent data from clinical research in high-resource settings, our results strongly argue for a reconsideration of CD4 cell threshold values currently used in treatment guidelines for resource-limited settings in order to maximize the impact of ART programmes on public health and individual wellbeing [49].…”

Comparison of Early CD4 T-Cell Count in HIV-1 Seroconverters in Côte d'Ivoire and France: The ANRS PRIMO-CI and SEROCO Cohorts

“…35 Moreover, the monitoring of CD4 + before antiretroviral treatment in Africa should be at least as frequent than in the North. 36 …”

Estimating the resources required in the roll-out of universal access to antiretroviral treatment in Zimbabwe

“…Monitoring individuals from early in their infection allows more individuals to enter care and for ART to be initiated at the right time 17. Currently, testing uptake is low in Zimbabwe39 40 48 but if 70% of infected individuals are tested sometime before they develop symptoms, and 90% of HIV infected pregnant women are referred from ANC, then 2 000 000 (30%) more individuals would be on ART by 2030 and 64 000 extra life-years would have been saved each year between 2005 and 2030.…”

“…Details of the mathematical model have been described previously17 but we briefly explain the key features again here.…”

“…ART programmes in different countries will manage patients and initiate ART in different ways and the pattern of ART uptake may change over time. The total resources required by alternative patient management strategies can be estimated by considering the range of disease states in a population,7 16 but this does not consider how monitoring effort or methods of ART initiation interact and are associated with survival outcomes and years spent on ART 17. Analyses that have examined the relative resource requirements of different initiation strategies11 have not represented practicalities in ART delivery, such as errors in CD4 counts, non-continuous monitoring of individuals or changes over time in the profile of patients entering care.…”