Spending Analysis for HIV and Opioid Use Disorders from 2010 to 2019: Variation by Area and Demographics

Abstract

Background: The United States spends more on health care than any other country, but the distribution of that spending across diseases corresponds only loosely to where health is lost. HIV and substance use disorders (SUD) illustrate the mismatch. Two measurement problems sustain it. First, national spending accounts report totals without disease-specific detail, and cost-effectiveness studies isolate single interventions, so neither tells a payer what it spends on a condition or what it obtains in return. Second, HIV and SUD rarely occur alone, and conventional cost estimates cannot separate the spending attributable to a condition from the spending attributable to everything else a patient has. Objectives: This dissertation estimated US health care spending on HIV and SUD from 2010 to 2019 and related that spending to health outcomes at the levels at which financing decisions are made. It pursued three aims: (1) estimate the incremental Medicare spending associated with HIV, SUD, their co-occurrence, and their combination with 23 other conditions, and test whether these effects differ by race, ethnicity, and age; (2) describe state and national HIV spending by payer and estimate the population viral suppression achievable at each level of spending per prevalent case; and (3) estimate state and national opioid use disorder (OUD) spending and burden and decompose their change into demographic and per-case components. Methods: Aim 1 analyzed encounter-level Medicare fee-for-service claims for beneficiaries aged 65 to 89, fitting three families of Gamma regressions and applying g-computation to predict spending with and without each co-occurring condition while setting other comorbidities to zero; uncertainty came from bootstrap resampling. Aims 2 and 3 used spending estimates from the Disease Expenditure Project (DEX) and prevalence and disability-adjusted life-year (DALY) estimates from the Global Burden of Disease (GBD) Study, both produced at the Institute for Health Metrics and Evaluation. Aim 2 built a state-level panel combining DEX all-payer HIV spending, Ryan White HIV/AIDS Program expenditures, and CDC AtlasPlus care-cascade indicators, then estimated a stochastic frontier of population viral suppression against spending per prevalent case. Aim 3 estimated OUD spending and DALYs for the nation and all 50 states and the District of Columbia and decomposed the 2010 to 2019 change into population size, age-sex structure, cases per person, and spending or DALYs per case. Results: In Aim 1, predicted 2019 annual spending per treated beneficiary was $2,873 (95% CI, $2,016–$4,081) for HIV alone and $278 (95% CI, $240–$322) for SUD alone. HIV-related spending tripled from 2010 to 2019 while SUD-related spending declined modestly. HIV produced the largest incremental increase for neoplasms ($189; 95% CI, $152–$228) and SUD for self-harm ($175; 95% CI, $53–$366); the joint effect of HIV and SUD was sub-additive for most conditions. Despite two-fold higher treated HIV prevalence among Black beneficiaries, incremental spending was statistically indistinguishable across racial, ethnic, and age groups. In Aim 2, total HIV spending rose from US$13.9 billion in 2010 to US$16.2 billion in 2019 as the private-insurance share grew from 39.9% to 47.6%; growth was attributable to rising prevalence and population size rather than to higher spending per case, and HIV DALYs fell 27.7%. Higher spending per prevalent case was associated with higher population viral suppression (β = +0.37; 95% CI, 0.02–0.72; p = 0.038), but states varied widely at comparable spending, from Montana on the frontier to South Dakota at 42% of achievable suppression. A lower out-of-pocket share of HIV spending was the one financing factor independently associated with sitting closer to the frontier. In Aim 3, OUD spending rose from $6.1 billion (95% UI, $5.8–$6.5 billion) to $12.9 billion (95% UI, $12.3–$13.4 billion), a 110.6% increase, while Medicaid's share grew from 51.6% to 63.3%. Prevalent cases rose from 2.5 million to 6.4 million and spending per prevalent case fell from $2,480 to $2,028. More cases per person contributed +132.0% of the change relative to 2010 spending, population growth +13.2%, lower spending per case −31.2%, and age-sex structure −3.4%. DALYs rose 123.5% while DALYs per case fell from 0.90 to 0.78; both per-case measures declined in 36 of 51 states. Conclusions: Growth in US spending on HIV and OUD between 2010 and 2019 reflected a rising number of people living with these conditions rather than costlier care per patient, and per-case burden fell alongside per-case spending. The financing challenge is therefore mostly prevalence driven and it falls disproportionately on Medicaid. Wide variation in the outcomes states achieve at similar per-case spending indicates that how dollars are allocated matters as much as how many are available, and that below-frontier states have room to gain by adapting the strategies of higher-performing peers.