A Modeling Study Points the Way to Stopping HIV Spread

March 19, 2020

The US government has ambitious goals to expand the number of people tested and treated for HIV in the coming years. A new study details the best interventions to make the biggest difference for the most people.

In 2015, the US government released a 5-year plan known as the National HIV/AIDS Strategy that outlined methods to lower the incidence of HIV infection and slow down the epidemic. The actions were predicated on “90-90-90” goals—90% of people with HIV would be diagnosed, 90% of those diagnosed would receive antiretroviral therapy (ART), and 90% of patients on ART would achieve viral suppression and be noninfectious by 2020.

Last year, the government revised this plan somewhat by announcing the goal of reducing new infections by 75% within 5 years and by 90% within a decade. However, along with possible increased funding in certain areas, the administration has implemented crucial budget cuts to programs that enable vulnerable citizens to access needed medical care and drugs. Meanwhile, thousands of new HIV cases continue to be diagnosed each year in the US, disproportionately affecting black and Hispanic men who engage in sex with other men.

A team of investigators from the British Columbia Centre for Excellence in HIV/AIDS in Vancouver, along with colleagues at other public health and medical institutions, completed an economic modeling study of 6 US cities in order to determine the evidence-based interventions that would result in better health outcomes in the most cost-effective manner. The study, which was published in The Lancet, simulated outbreaks in each city, then examined multiple combinations of strategies to prevent HIV, expand testing, increase treatment rates, and retain and re-engage patients in care.

The study’s focus was the number of HIV infections, quality-adjusted life years (QALYs), total costs, and incremental cost-effectiveness ratio (ICER), which measures the cost effectiveness of a particular health intervention compared with others. Modeling forecasts looked at outcomes through 2040.

The cities in the study included Seattle, Miami, Atlanta, Baltimore, New York, and Los Angeles, which together account for nearly a quarter of all Americans living with HIV. The demographics and facilities available in each city are different enough that the investigators felt they would capture the breadth of strategies needed. The interventions tested in combination ranged from the protective, including fresh syringe programs, medications for opioid users, and pre-exposure prophylaxis (PrEP); the diagnostic, including testing in the emergency room or primary-care office and reminders to test; and the treatment based, including immediate ART, case management, and connection to care.

Some of the strategies that produced the best outcomes included treating opioid users with buprenorphine or methadone; sending electronic HIV testing reminders; nurse-initiated rapid testing; case management; and rapid ART initiation. Each city assessed yielded a different combination of optimal strategies, with different strategies being effective in varying locales.

Overall, the team predicted that the combination strategies could lower HIV rates by anywhere from 30.7% in Seattle to 50.1% in New York. Across the board, the weighted average was a rate reduction of 37.9%. Scaling up from previously documented strategies, the investigators determined that the optimal combination strategies would result in QALY gains of 2,046 in Seattle, all the way up to 23,591 in Los Angeles, by 2040. ICERs showed $95,416 per QALY in Seattle, but money actually would be saved in Atlanta, Baltimore, and Miami, a city that led the nation in new HIV diagnoses in 2017.

The total national expenditure required to meet HIV-ending targets would be $3.51 billion spent over a decade. “This investment would be frontloaded, peaking at an annual expenditure of $559 million in 2024, equating to 2.7% of all federal domestic expenditures on the care and prevention of HIV/AIDS in 2018, with the timing of positive incremental costs varying by city and cost component,” the authors wrote, noting that the funds needed are almost twice what the government has allotted for HIV-reduction strategies. “These investments would nonetheless provide long-term value in each setting, with upfront investments offset by downstream reductions in health-care costs as a result of averted infections and delayed disease progression.”

The study took into account only interventions with direct bearing on HIV outcomes. The authors stressed that factors such as poverty and stigma contribute greatly to the spread of HIV, and any efforts to stem the tide of HIV must include solutions to overcome these issues, likely involving further expenditures.