PS-SiZer map to investigate significant features of body-weight profile changes in HIV infected patients in the IeDEA Collaboration

Objectives: We extend the method of Significant Zero Crossings of Derivatives (SiZer) to address within-subject correlations of repeatedly collected longitudinal biomarker data and the computational aspects of the methodology when analyzing massive biomarker databases. SiZer is a powerful visualization tool for exploring structures in curves by mapping areas where the first derivative is increasing, decreasing or does not change (plateau) thus exploring changes and normalization of biomarkers in the presence of therapy. Methods: We propose a penalized spline SiZer (PS-SiZer) which can be expressed as a linear mixed model of the longitudinal biomarker process to account for irregularly collected data and within-subject correlations. Through simulations we show how sensitive PS-SiZer is in detecting existing features in longitudinal data versus existing versions of SiZer. In a real-world data analysis PS-SiZer maps are used to map areas where the first derivative of weight change after antiretroviral therapy (ART) start is significantly increasing, decreasing or does not change, thus exploring the durability of weight increase after the start of therapy. We use weight data repeatedly collected from persons living with HIV initiating ART in five regions in the International Epidemiologic Databases to Evaluate AIDS (IeDEA) worldwide collaboration and compare the durability of weight gain between ART regimens containing and not containing the drug stavudine (d4T), which has been associated with shorter durability of weight gain. Results: Through simulations we show that the PS-SiZer is more accurate in detecting relevant features in longitudinal data than existing SiZer variants such as the local linear smoother (LL) SiZer and the SiZer with smoothing splines (SS-SiZer). In the illustration we include data from 185,010 persons living with HIV who started ART with a d4T (53.1%) versus non-d4T (46.9%) containing regimen. The largest difference in durability of weight gain identified by the SiZer maps was observed in Southern Africa where weight gain in patients treated with d4T-containing regimens lasted 59.9 weeks compared to 133.8 weeks for those with non-d4T-containing regimens. In the other regions, persons receiving d4T-containing regimens experienced weight gains lasting 38-62 weeks versus 55-93 weeks in those receiving non-d4T-based regimens. Discussion: PS-SiZer, a SiZer variant, can handle irregularly collected longitudinal data and within-subject correlations and is sensitive in detecting even subtle features in biomarker curves

Estimated mortality of adult HIV-infected patients starting treatment with combination antiretroviral therapy

To provide estimates of mortality among HIV-infected patients starting combination antiretroviral therapy

Estimated mortality of adult HIV-infected patients starting treatment with combination antiretroviral therapy

OBJECTIVE: To provide estimates of mortality among HIV-infected patients starting combination antiretroviral therapy. METHODS: We report on the death rates from 122 925 adult HIV-infected patients aged 15 years or older from East, Southern and West Africa, Asia Pacific and Latin America. We use two methods to adjust for biases in mortality estimation resulting from loss from follow-up, based on double-sampling methods applied to patient outreach (Kenya) and linkage with vital registries (South Africa), and apply these to mortality estimates in the other three regions. Age, gender and CD4 count at the initiation of therapy were the factors considered as predictors of mortality at 6, 12, 24 and >24 months after the start of treatment. RESULTS: Patient mortality was high during the first 6 months after therapy for all patient subgroups and exceeded 40 per 100 patient years among patients who started treatment at low CD4 count. This trend was seen regardless of region, demographic or disease-related risk factor. Mortality was under-reported by up to or exceeding 100% when comparing estimates obtained from passive monitoring of patient vital status. CONCLUSIONS: Despite advances in antiretroviral treatment coverage many patients start treatment at very low CD4 counts and experience significant mortality during the first 6 months after treatment initiation. Active patient tracing and linkage with vital registries are critical in adjusting estimates of mortality, particularly in low- and middle-income settings

Effects of national adoption of Treat-All guidelines on pre-ART CD4 testing and viral load monitoring after ART initiation: A regression discontinuity analysis

BACKGROUND: The World Health Organization's Treat-All guidance recommends CD4 testing prior to antiretroviral treatment (ART) initiation, and routine viral load (VL) monitoring (over CD4 monitoring) for patients on ART. METHODS: We used regression discontinuity analyses to estimate changes in CD4 testing and VL monitoring among 547,837 ART-naïve patients enrolling in HIV care during 2006-2018 at 225 clinics in 26 countries where Treat-All policies were adopted. We examined CD4 testing within 12 months before and VL monitoring 6 months after ART initiation among adults (≥20 years), adolescents (10-19 years) and children (0-9 years) in low/lower-middle income countries (L/LMICs) and high/upper-middle income countries (H/UMICs). RESULTS: Treat-All adoption led to an immediate decrease in pre-ART CD4 testing among adults in L/LMICs, from 57.0% to 48.1% (-8.9 percentage points [pp]; 95% CI: -11.0, -6.8), and a small increase in in H/UMICs, from 90.1 to 91.7% (+1.6pp; 95% CI: 0.2, 3.0), with no changes among adolescents or children; decreases in pre-ART CD4 testing accelerated after Treat-All adoption in L/LMICs. In L/LMICs, VL monitoring after ART initiation was low among all patients just before Treat-All; while there was no immediate change at Treat-All adoption, VL monitoring trends significantly increased afterwards. In H/UMICs, VL monitoring increased among adults immediately after Treat-All adoption, from 58.2% to 61.1% (+2.9pp; 95% CI: 0.5, 5.4), with no significant changes among adolescents/children. CONCLUSIONS: While on-ART VL monitoring has improved in L/LMICs, Treat-All adoption has accelerated and disparately worsened suboptimal pre-ART CD4 monitoring, which may compromise care outcomes for individuals with advanced HIV