Miaoqing
Jia

Antibiotics lose power to kill microbes through excessive use, commonly known as antibiotic resistance, which is modeled by future cost increase from current use. The first best incorporates the future cost externality due to current consumption. Resistance and consumer welfare deviate from first best in various market structures. Low prices under competition lead to high consumption and resistance. Competitive managed-care plans use rationing contracts, which partially internalize the resistance cost externality by restricting use. A drug monopolist fully internalizes the externality but sets a high price. We derive necessary and sufficient conditions for higher consumer surplus under monopoly than competition.

Facing a potential entrant, an incumbent may consider entry deterrence and accommodation. To deter entry, the incumbent reduces current sales to lower future cost, which alleviates antibiotic resistance. Entry accommodation gives rise to two countervailing effects: sharing the market weakens the incumbent's incentive to internalize the cost effect, raising production and resistance; but a lower future cost raises profit, leading the incumbent to reduce production and mitigate resistance.

Importance. Enrollment in integrated dual eligible special needs plans (D-SNPs) — including highly integrated D-SNPs (HIDE-SNPs) and fully integrated D-SNPs (FIDE-SNPs) — has increased among dual eligibles with serious mental illness (SMI), yet how it relates to acute care use remains unknown.

Objective. To examine the association between integrated D-SNP enrollment and acute care utilization among dual eligibles with SMI in 2022.

Design, Setting, and Participants. Retrospective cohort study of a 20% sample of dual eligibles with SMI using Medicare claims, including traditional Medicare fee-for-service (FFS) claims and Medicare Advantage (MA) encounter data.

Main Outcomes and Measures. Overall, psychiatric, and preventable hospitalization and emergency department (ED) visits, comparing enrollees in integrated D-SNPs with those in traditional Medicare, standard MA, and coordination-only (CO) D-SNPs.

Results. Among 349,163 dual eligibles with SMI (mean age 62 years; 63.1% female), after covariate adjustment HIDE-SNP enrollment was associated with a lower likelihood of overall hospitalization than Medicare FFS (−6.8 percentage points [pp]), standard MA (−1.9 pp), and CO D-SNPs (−2.4 pp), and lower psychiatric hospitalization across the same comparisons. FIDE-SNP enrollment was also associated with lower overall and psychiatric hospitalization versus CO D-SNPs. Both HIDE- and FIDE-SNPs were associated with lower preventable hospitalization than CO D-SNPs and lower 30-day readmission than Medicare FFS; differences in ED outcomes were smaller and less consistent.

Conclusions and Relevance. Enrollment in integrated D-SNPs, particularly HIDE-SNPs, was associated with lower overall, psychiatric, and preventable hospitalization among dual eligibles with SMI. Future research should assess causal relationships between integrated D-SNPs and acute care use in this population.

GLP-1 receptor agonists (GLP-1 RAs) are transforming obesity and type 2 diabetes management, but access remains strongly shaped by payer coverage and utilization management tools, such as prior authorization, that may result in prescription denials. National, patient-level evidence on GLP-1 RA denial across payer types is needed to understand the evolving landscape of patient access.

Using a multi-payer claims database, we examined GLP-1 RA prescription denial among 3,221,310 individuals with a GLP-1 RA prescription claim from 2018 to 2024. Overall, 12.5% experienced at least one denied claim, with rates rising from 11.3% in 2018 to a peak of 16.9% in 2020 before declining to 9.3% in 2024. Denial was higher among Medicaid beneficiaries and new initiators across all years. New initiators, Medicaid coverage, obesity-only indication, tirzepatide prescription, and Black race were associated with higher odds of denial.

Results suggest that utilization management tools are shaping patients' access to GLP-1 RAs.

Background. Health systems increasingly screen for patients' social needs, but evidence is limited on which specific needs are most associated with subsequent acute care use.

Objective. To examine associations between patient-reported social needs and subsequent acute care utilization in a large safety-net population.

Design. Retrospective cohort study linking 2023 social needs screening data from a large safety-net health system to longitudinal electronic health records from a multi-health system clinical research network.

Participants. 20,337 adults with a primary care visit who completed social needs screening in 2023.

Main Measures. Positive screening for nine social needs domains (e.g., food insecurity, transportation-related delayed care). Outcomes were any hospitalization, any ED visit, preventable hospitalization, and preventable ED visit, using multivariable logistic regression adjusting for demographics, comorbidities, and neighborhood social conditions.

Key Results. Overall, 15.9% screened positive for ≥1 social need; the most prevalent were food insecurity (5.9%) and problems with residence (5.6%). After adjustment, positive screening for transportation-related delayed care was associated with a 6.8-percentage-point increase in the probability of ≥1 hospitalization, an 8.4-point increase in ≥1 ED visit, a 1.2-point increase in ≥1 preventable hospitalization, and a 4.2-point increase in ≥1 preventable ED visit. Housing-related problems were associated with a 4.1-point increase in ≥1 ED visit.

Conclusions. In a safety-net setting, transportation barriers showed the strongest and most consistent associations with subsequent acute care use, suggesting targeted transportation support and care-navigation strategies may be critical components of social care interventions.

Background. Nearly one in five hospice enrollees is discharged alive ("live discharge"), a share that has grown in recent years, yet post-discharge prognosis is highly variable and poorly characterized.

Methods. Using a 20% random sample of 2014–2019 Medicare fee-for-service beneficiaries, we applied growth mixture modeling to biweekly Medicare spending over the 12 months following hospice live discharge, and multinomial logistic regression to identify characteristics associated with each trajectory.

Results. We identified five distinct post-discharge spending trajectories, ranging from rapid near-term mortality to prolonged survival with persistently high spending. Reason for live discharge, hospice care setting, and clinical complexity were the strongest predictors of trajectory membership.

Conclusions. Substantial heterogeneity in post-discharge trajectories points to opportunities for more personalized care planning after hospice live discharge.

I investigate the impact of inappropriate medicine usage on future healthcare costs in a multi-period model. The negative externality — any current medicine consumption raises future costs for the entire population — leads to market failures. The model includes forward-looking and myopic patients: the former recognize the long-term externalities of consumption, while the latter focus solely on immediate benefits. Their interaction exacerbates inefficiency, as forward-looking patients may cut consumption to limit future cost increases while myopic patients over-consume.

In a perfectly competitive market, marginal-cost pricing is inefficient because of myopic over-consumption. Under a monopolistic structure, pricing above marginal cost can curb overuse and improve social welfare by controlling future cost jumps. I further show that policy interventions such as taxes or subsidies can correct the market inefficiencies and improve healthcare outcomes.

Starting in 2010, the Chinese government implemented a series of national health care reforms to ensure accessible and affordable care, choosing several pilot areas with staggered implementation. Using ongoing national survey data from the China Health and Retirement Longitudinal Study (CHARLS), I analyze the impact of reform on patients' self-treatment behavior and on the severity of antibiotic abuse in China.

Through a combination of propensity score matching and difference-in-differences methods, I find that although the reform effectively reduces average monthly medical expenditures for people living within pilot areas, it is ineffective in limiting people's self-medication with antibiotics. Surprisingly, people living in pilot areas are more likely to use antibiotics after the reform.

I study informal gift exchange in the public health sector in China. In the public system, a physician receives a fixed salary and additional payments from patients; a guilt effect from violating professional norms limits the size of informal payments. In the private system, the guilt effect vanishes because informal payment is legalized. Without the fixed salary, the physician in the private system abandons patients who offer low payments.

The distribution of patients' wealth levels and the physician's outside option determine relative welfare across the two systems. If too many patients are left behind, the regulator will support the public system.