Research
Summary
Dr Machado's research is interdisciplinary. She works at the intersection of health policy, health services research, and health economics. Her current research analyses the
relationship between health and wealth, and how that is shaped by health system design and features.
Using the Health and Retirement Survey (HRS), she studied how midlife wealth mobility is linked long-term cardiovascular outcomes. She has also used detailed clinical data from the United Network for Organ Sharing to study the evolution of the payer mix in access to heart failure and transplantation care, as well as the interaction between cardio-metabolic comorbidities and heart transplants. Her focus on cardiovascular disease risk factors and access to care has led to another study quantifying the relationship between Medicaid expansion, in the US, and the use of cholesterol-lowering drugs.
She has also conducted a number of studies analyzing healthcare systems and access to care through the lens of organ donation and transplantation, with a focus on solid organs and organ failure in the US. Taken together, these studies have led to several first-authored articles in top medical journals such as the Journal of the American Medical Association family (JAMA Cardiology, JAMA Network Open), and the New England Journal of Medicine.
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See CV for publication details.
Featured Research
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Association Between Wealth and Mortality in the United States and Europe
with Ilias Kyriopoulos, John Orav, and Irene Papanicolas
Published April 2, 2025
N Engl J Med 2025;392:1310-1319
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Background
Amid growing wealth disparity, we have little information on how health among older Americans compares with that among older Europeans across the distribution of wealth.
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Methods
We performed a longitudinal, retrospective cohort study involving adults 50 to 85 years of age who were included in the Health and Retirement Study and the Survey of Health, Ageing, and Retirement in Europe between 2010 and 2022. Wealth quartiles were defined according to age group and country, with quartile 1 comprising the poorest participants and quartile 4 the wealthiest. Mortality and Kaplan–Meier curves were estimated for each wealth quartile across the United States and 16 countries in northern and western, southern, and eastern Europe. We used Cox proportional-hazards models that included adjustment for baseline covariates (age group, sex, marital status [ever or never married], educational level [any or no college education], residence [rural or nonrural], current smoking status [smoking or nonsmoking], and absence or presence of a previously diagnosed long-term condition) to quantify the association between wealth quartile and all-cause mortality from 2010 through 2022 (the primary outcome).
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Results
Among 73,838 adults (mean [±SD] age, 65±9.8 years), a total of 13,802 (18.7%) died during a median follow-up of 10 years. Across all participants, greater wealth was associated with lower mortality, with adjusted hazard ratios for death (quartile 2, 3, or 4 vs. quartile 1) of 0.80 (95% confidence interval [CI], 0.76 to 0.83), 0.68 (95% CI, 0.65 to 0.71), and 0.60 (95% CI, 0.57 to 0.63), respectively. The gap in survival between the top and bottom wealth quartiles was wider in the United States than in Europe. Survival among the participants in the top wealth quartiles in northern and western Europe and southern Europe appeared to be higher than that among the wealthiest Americans. Survival in the wealthiest U.S. quartile appeared to be similar to that in the poorest quartile in northern and western Europe.
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Conclusions
In cohort studies conducted in the United States and Europe, greater wealth was associated with lower mortality, and the association between wealth and mortality appeared to be more pronounced in the United States than in Europe.