Age-associated dementia among older people aging with HIV in the US: a modeling study.

OBJECTIVE: Almost 400 000 people with HIV (PWH) in the United States are over age 55 years and at risk for age-associated dementias (AAD), including Alzheimer's disease and vascular contributions to cognitive impairment and dementia (VCID). We projected the cumulative incidence and mortality associated with AAD among PWH at least 60 years in the United States compared with the general population. DESIGN/METHODS: Integrating the CEPAC and AgeD-Pol models, we simulated two cohorts of male and female individuals at least 60 years old: PWH, and general US population. We estimated AAD incidence and AAD-associated mortality rates. Projected outcomes included AAD cumulative incidence, life expectancy, and quality-adjusted life-years (QALYs). We performed sensitivity and scenario analyses on AAD-specific (e.g. incidence) and HIV-specific (e.g. disengagement from HIV care) parameters, as well as premature aging among PWH. RESULTS: We projected that 22.1%/16.3% of 60-year-old male individuals/female individuals with HIV would develop AAD by 80 years compared with 15.9%/13.3% of male individuals/female individuals in the general population. Accounting for age-associated and dementia-associated quality of life, 60-year-old PWH would have a lower life expectancy (QALYs): 17.4 years (14.1 QALYs) and 16.8 years (13.4 QALYs) for male and female individuals, respectively, compared with the general population [men, 21.7 years (18.4 QALYs); women, 24.7 years (20.2 QALYs)]. AAD cumulative incidence was most sensitive to non-HIV-related mortality, engagement in HIV care, and AAD incidence rates. CONCLUSION: Projected estimates of AAD-associated morbidity, mortality, and quality of life can inform decision-makers and health systems planning as the population of PWH ages. Improved AAD prevention, treatment, and supportive care planning are critical for people aging with HIV.

The association between all-cause mortality and HIV acquisition risk groups in the United States, 2001-2014.

OBJECTIVE: To investigate associations between all-cause mortality and human immunodeficiency virus (HIV) acquisition risk groups among people without HIV in the United States. METHODS: We used data from 23,657 (NHANES) participants (2001-2014) and the Linked Mortality File to classify individuals without known HIV into HIV acquisition risk groups: people who ever injected drugs (ever-PWID); men who have sex with men (MSM); heterosexually active people at increased risk for HIV (HIH), using low income as a proxy for increased risk. We used Cox proportional hazards models to estimate adjusted and unadjusted all-cause mortality hazard ratios (HR) with 95% confidence intervals (CI). RESULTS: Compared with sex-specific heterosexually active people at average risk for HIV (HAH), the adjusted HR (95% CI) were: male ever-PWID 1.67 (1.14, 2.46), female ever-PWID 3.50 (2.04, 6.01), MSM 1.51 (1.00, 2.27), male HIH 1.68 (1.04, 2.06), female HIH 2.35 (1.87, 2.95), and male ever-PWID 1.67 (1.14, 2.46). CONCLUSIONS: Most people at increased risk for HIV in the US experience higher all-cause mortality than people at average risk. Strategies addressing social determinants that increase HIV risk should be incorporated into HIV prevention and other health promotion programs.

Development and validation of the age-associated dementia policy (AgeD-Pol) computer simulation model in the USA and Europe.

OBJECTIVE: To develop and validate a novel, microsimulation model that accounts for the prevalence and incidence of age-associated dementias (AAD), disease progression and associated mortality. DESIGN, DATA SOURCES AND OUTCOME MEASURES: We developed the AAD policy (AgeD-Pol) model, a microsimulation model to simulate the natural history, morbidity and mortality associated with AAD. We populated the model with age-stratified and sex-stratified data on AAD prevalence, AAD incidence and mortality among people with AAD. We first performed internal validation using data from the Adult Changes in Thought (ACT) cohort study. We then performed external validation of the model using data from the Framingham Heart Study, the Rotterdam Study and Kaiser Permanente Northern California (KPNC). We compared model-projected AAD cumulative incidence and mortality with published cohort data using mean absolute percentage error (MAPE) and root-mean-square error (RMSE). RESULTS: In internal validation, the AgeD-Pol model provided a good fit to the ACT cohort for cumulative AAD incidence, 10.4% (MAPE, 0.2%) and survival, 66.5% (MAPE, 8.8%), after 16 years of follow-up among those initially aged 65-69 years. In the external validations, the model-projected lifetime cumulative incidence of AAD was 30.5%-32.4% (females) and 16.7%-23.0% (males), using data from the Framingham and Rotterdam cohorts, and AAD cumulative incidence was 21.5% over 14 years using KPNC data. Model projections demonstrated a good fit to all three cohorts (MAPE, 0.9%-9.0%). Similarly, model-projected survival provided good fit to the Rotterdam (RMSE, 1.9-3.6 among those with and without AAD) and KPNC cohorts (RMSE, 7.6-18.0 among those with AAD). CONCLUSIONS: The AgeD-Pol model performed well when validated to published data for AAD cumulative incidence and mortality and provides a useful tool to project the AAD disease burden for health systems planning in the USA.

Health Impact and Cost-Effectiveness of HIV Testing, Linkage, and Early Antiretroviral Treatment in the Botswana Combination Prevention Project.

BACKGROUND: The Botswana Combination Prevention Project tested the impact of combination prevention (CP) on HIV incidence in a community-randomized trial. Each trial arm had ∼55,000 people, 26% HIV prevalence, and 72% baseline ART coverage. Results showed intensive testing and linkage campaigns, expanded antiretroviral treatment (ART), and voluntary male medical circumcision referrals increased coverage and decreased incidence over ∼29 months of follow-up. We projected lifetime clinical impact and cost-effectiveness of CP in this population. SETTING: Rural and periurban communities in Botswana. METHODS: We used the Cost-Effectiveness of Preventing AIDS Complications model to estimate lifetime health impact and cost of (1) earlier ART initiation and (2) averting an HIV infection, which we applied to incremental ART initiations and averted infections calculated from trial data. We determined the incremental cost-effectiveness ratio [US$/quality-adjusted life-years (QALY)] for CP vs. standard of care. RESULTS: In CP, 1418 additional people with HIV initiated ART and an additional 304 infections were averted. For each additional person started on ART, life expectancy increased 0.90 QALYs and care costs increased by $869. For each infection averted, life expectancy increased 2.43 QALYs with $9200 in care costs saved. With CP, an additional $1.7 million were spent on prevention and $1.2 million on earlier treatment. These costs were mostly offset by decreased care costs from averted infections, resulting in an incremental cost-effectiveness ratio of $79 per QALY. CONCLUSIONS: Enhanced HIV testing, linkage, and early ART initiation improve life expectancy, reduce transmission, and can be cost-effective or cost-saving in settings like Botswana.

Rates of Sexually Transmitted Infection Diagnoses Among US Youth With Perinatally and Nonperinatally Acquired HIV.

BACKGROUND: Of new sexually transmitted infections (STIs) in the United States, 50% occur among youth aged 15 to 24 years. Previous studies among youth with HIV (YHIV) do not distinguish STI trends among individuals with perinatally (YPHIV) and nonperinatally (YNPHIV) acquired HIV. METHODS: Among 3 Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) studies conducted between 2009 and 2015, we estimated incident diagnoses of trichomonal, bacterial, viral, and overall STIs stratified by sex assigned at birth, mode of HIV acquisition (perinatal [YPHIV] and nonperinatal [YNPHIV]), age (13-17 and 18-24 years), CD4 count (<200, 200-499, and ≥500/µL), and HIV viral load (VL) (<400 and ≥400 copies/mL). RESULTS: Among 3131 YHIV, across the 3 studies, mean (SD) age was 20.6 (2.6) years, 888 (28%) were female, 2498 (80%) had nonperinatal HIV acquisition recorded, and 2298 (73%) were African American/Black. Mean follow-up was 0.9 (0.3) years. Compared with YPHIV, YNPHIV spent less person-time with VL <400 copies/mL (47% vs. 53%) and more time off antiretroviral therapy (49% vs. 15%), and had higher overall STI rates (males, 65.9 vs. 8.5/100 person-years [PY]; females, 54.7 vs. 17.2/100 PY). Among YPHIV, bacterial STIs were higher during person-time spent with VL ≥400 vs. <400 copies/mL (male YPHIV, 10.9 vs. 0.6/100 PY; female YPHIV, 11.2 vs. 2.9/100 PY); no difference was observed among YNPHIV, which may be due to concurrent acquisition of HIV and other STIs and limited follow-up. CONCLUSIONS: Compared with YPHIV, YNPHIV spent less time on antiretroviral therapy and virologically suppressed; YNPHIV also had higher STI diagnosis rates. Very high STI diagnosis rates among YHIV, including among those without virologic suppression, highlight the importance of youth-focused efforts to support durable virologic suppression and identify and treat STIs.

Cost-effectiveness of Frequent HIV Screening Among High-risk Young Men Who Have Sex With Men in the United States.

BACKGROUND: Of new HIV infections in the US, 20% occur among young men who have sex with men (YMSM, ages 13-24), but >50% of YMSM with HIV are unaware of their status. Using Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) data, we projected the clinical benefit and cost-effectiveness of frequent HIV screening among high-risk YMSM from age 15. METHODS: Using a mathematical simulation, we examined 3 screening strategies: Yearly, 6-monthly, and 3-monthly, each in addition to the Status quo (SQ, 0.7-10.3% screened/year, stratified by age). We used published data (YMSM-specific when available) including: HIV incidences (0.91-6.41/100PY); screen acceptance (80%), linkage-to-care/antiretroviral therapy (ART) initiation (76%), HIV transmission (0.3-86.1/100PY, by HIV RNA), monthly ART costs ($2290-$3780), and HIV per-screen costs ($38). Projected outcomes included CD4 count at diagnosis, primary HIV transmissions from ages 15-30, quality-adjusted life expectancy, costs, and incremental cost-effectiveness ratios (ICERs, $/quality-adjusted life-year saved [QALY]; threshold ≤$100 000/QALY). RESULTS: Compared to SQ, all strategies increased projected CD4 at diagnosis (296 to 477-515 cells/µL) and quality-adjusted life expectancy from age 15 (44.4 to 48.3-48.7 years) among YMSM acquiring HIV. Compared to SQ, all strategies increased discounted lifetime cost for the entire population ($170 800 to $178 100-$185 000/person). Screening 3-monthly was cost-effective (ICER: $4500/QALY) compared to SQ and reduced primary transmissions through age 30 by 40%. Results were most sensitive to transmission rates; excluding the impact of transmissions, screening Yearly was ≤$100 000/QALY (ICER: $70 900/QALY). CONCLUSIONS: For high-risk YMSM in the US, HIV screening 3-monthly compared to less frequent screening will improve clinical outcomes and be cost-effective.

Cost-effectiveness of public health strategies for COVID-19 epidemic control in South Africa: a microsimulation modelling study.

BACKGROUND: Health-care resource constraints in low-income and middle-income countries necessitate the identification of cost-effective public health interventions to address COVID-19. We aimed to develop a dynamic COVID-19 microsimulation model to assess clinical and economic outcomes and cost-effectiveness of epidemic control strategies in KwaZulu-Natal province, South Africa. METHODS: We compared different combinations of five public health interventions: health-care testing alone, where diagnostic testing is done only for individuals presenting to health-care centres; contact tracing in households of cases; isolation centres, for cases not requiring hospital admission; mass symptom screening and molecular testing for symptomatic individuals by community health-care workers; and quarantine centres, for household contacts who test negative. We calibrated infection transmission rates to match effective reproduction number (Re) estimates reported in South Africa. We assessed two main epidemic scenarios for a period of 360 days, with an Re of 1·5 and 1·2. Strategies with incremental cost-effectiveness ratio (ICER) of less than US$3250 per year of life saved were considered cost-effective. We also did sensitivity analyses by varying key parameters (Re values, molecular testing sensitivity, and efficacies and costs of interventions) to determine the effect on clinical and cost projections. FINDINGS: When Re was 1·5, health-care testing alone resulted in the highest number of COVID-19 deaths during the 360-day period. Compared with health-care testing alone, a combination of health-care testing, contact tracing, use of isolation centres, mass symptom screening, and use of quarantine centres reduced mortality by 94%, increased health-care costs by 33%, and was cost-effective (ICER $340 per year of life saved). In settings where quarantine centres were not feasible, a combination of health-care testing, contact tracing, use of isolation centres, and mass symptom screening was cost-effective compared with health-care testing alone (ICER $590 per year of life saved). When Re was 1·2, health-care testing, contact tracing, use of isolation centres, and use of quarantine centres was the least costly strategy, and no other strategies were cost-effective. In sensitivity analyses, a combination of health-care testing, contact tracing, use of isolation centres, mass symptom screening, and use of quarantine centres was generally cost-effective, with the exception of scenarios in which Re was 2·6 and when efficacies of isolation centres and quarantine centres for transmission reduction were reduced. INTERPRETATION: In South Africa, strategies involving household contact tracing, isolation, mass symptom screening, and quarantining household contacts who test negative would substantially reduce COVID-19 mortality and would be cost-effective. The optimal combination of interventions depends on epidemic growth characteristics and practical implementation considerations. FUNDING: US National Institutes of Health, Royal Society, Wellcome Trust.

Cost-effectiveness of public health strategies for COVID-19 epidemic control in South Africa: a microsimulation modelling study.

BACKGROUND: Healthcare resource constraints in low and middle-income countries necessitate selection of cost-effective public health interventions to address COVID-19. METHODS: We developed a dynamic COVID-19 microsimulation model to evaluate clinical and economic outcomes and cost-effectiveness of epidemic control strategies in KwaZulu-Natal, South Africa. Interventions assessed were Healthcare Testing (HT), where diagnostic testing is performed only for those presenting to healthcare centres; Contact Tracing (CT) in households of cases; Isolation Centres (IC), for cases not requiring hospitalisation; community health worker-led Mass Symptom Screening and molecular testing for symptomatic individuals (MS); and Quarantine Centres (QC), for household contacts who test negative. Given uncertainties about epidemic dynamics in South Africa, we evaluated two main epidemic scenarios over 360 days, with effective reproduction numbers (Re) of 1·5 and 1·2. We compared HT, HT+CT, HT+CT+IC, HT+CT+IC+MS, HT+CT+IC+QC, and HT+CT+IC+MS+QC, considering strategies with incremental cost-effectiveness ratio (ICER)