Publications by Year: 2026

IMPORTANCE: There were well-documented changes in health care use during the COVID-19 pandemic. Little is known about whether there were any associated decreases in claims-based comorbidity ascertainment that might have relevance to health services and policy research.

OBJECTIVE: To quantify differences in claims-based comorbidity assessment in Medicare beneficiaries pre- vs post-COVID-19.

DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study analyzed data from the 30 Chronic Conditions Warehouse 1- or 2-year lookback claims algorithms to ascertain each comorbidity with exact date ranges for all fee-for-service (FFS) and Medicare Advantage (MA) beneficiaries. Data were analyzed from April 2025 to April 2026.

EXPOSURES: The first quarter (Q1) of 2019 and 2022 were evaluated as pre- and post-COVID-19, respectively.

MAIN OUTCOMES AND MEASURES: The main outcomes were comorbidities per beneficiary and association between each comorbidity and mortality in 2019 vs 2022. The changes in prevalence of each comorbidity between 2019 and 2022 were analyzed and fit models within disjoint population subgroups were combined via multilevel meta-analysis models to determine whether each comorbidity's association with mortality changed over time.

RESULTS: This study included 59 514 042 beneficiaries in 2019 (32 351 732 females [54.4%]; 50 814 834 aged 65 years or older [85.4%]) and 63 202 599 beneficiaries in 2022 (34 377 560 females [54.4%]; 55 197 435 aged 65 years or older [87.3%]). The mean number of coded comorbidities per beneficiary decreased from 3.85 to 3.62 for FFS and 4.54 to 4.39 for MA (-0.15) between 2019 and 2022. In FFS, 19 comorbidities (63.3%) decreased, 2 (6.7%) were unchanged, and 9 (30%) increased. In MA, 14 comorbidities (46.7%) decreased, 7 (23.3%) were unchanged, and 9 (30%) increased. In multivariable analyses pooled across FFS and MA, 11 comorbidities (36.7%) were more positively associated with mortality, and 4 (13.3%) were more negatively associated with mortality in Q1 2022 than in Q1 2019.

CONCLUSIONS AND RELEVANCE: Coded levels of many comorbidities in Medicare were lower postpandemic than prepandemic, and the association of these codes with mortality changed. This suggests that across the COVID-19 pandemic comorbidity capture was affected by utilization changes, and the association between comorbidities and mortality changed as a result. Analyses that include immediately pre- or post-COVID-19 data and condition inferences on membership in utilization-based disease groups, or use claims-based risk adjustment, may be subject to bias.

BACKGROUND: Cardiovascular-kidney-metabolic (CKM) syndrome highlights the inter-related nature of cardiometabolic risk factors, kidney disease, and cardiovascular disease (CVD) and represents an important target for intervention amid rising cardiovascular mortality in the United States. However, contemporary treatment patterns of major cardiometabolic risk factors in this high-risk population are not well defined.

OBJECTIVES: The purpose of this study was to characterize national treatment rates of hypertension, diabetes, and hyperlipidemia among U.S. adults with CKM syndrome and to assess risk factor control among treated individuals from 2015 through 2023.

METHODS: We analyzed data from adults aged ≥20 years with CKM stage 2 and above who participated in the National Health and Nutrition Examination Survey from 2015 through August 2023. Treatment rates for hypertension, diabetes, and hyperlipidemia and rates of blood pressure, glycemic, and cholesterol control among treated individuals were estimated using age- and sex-adjusted analyses that accounted for the complex survey design.

RESULTS: The study included 6,384 adults with CKM stage 2 and above (weighted mean age 44.2 years; 51.2% women). Only approximately one-half of adults with hypertension (51.3% [95% CI: 49.7%-52.8%]) or hyperlipidemia (48.8% [95% CI: 46.7%-51.0%]) were receiving treatment, while diabetes treatment rates were higher (83.4% [95% CI: 80.1%-86.6%]). Among treated individuals, blood pressure control was achieved in 44.7% (95% CI: 41.6%-47.7%), glycemic control in 47.3% (95% CI: 42.7%-51.8%), and cholesterol control in 68.2% (95% CI: 65.2%-71.1%). Treatment rates for hypertension and hyperlipidemia increased across higher risk strata, while blood pressure and glycemic control were lower among treated adults with higher 10-year CVD risk. Adults aged 20-44 years consistently had the lowest treatment rates across all 3 conditions (hypertension 27.6% [95% CI: 24.8%-30.3%], diabetes 73.7% [95% CI: 63.8%-83.7%], hyperlipidemia 19.7% [95% CI: 15.2%-24.3%]), while women were less likely than men to receive treatment for diabetes and hyperlipidemia. Among racial and ethnic subgroups, Hispanic adults had the lowest treatment rates for hypertension and hyperlipidemia.

CONCLUSIONS: Among U.S. adults with CKM syndrome, treatment of hypertension and hyperlipidemia was low, and fewer than one-half of treated individuals achieved blood pressure or glycemic control. Gaps in treatment initiation were most pronounced among young adults, women, and Hispanic adults, and inadequate risk factor control was particularly evident among those with higher cardiovascular risk. These findings highlight substantial opportunities to improve cardiometabolic care in this high-risk population.

BACKGROUND: Cardiometabolic risk factors are major contributors to premature mortality in the United States. Little is known about recent changes in the cardiometabolic health of US adults by income level, particularly after the COVID-19 pandemic.

OBJECTIVE: To assess changes in the cardiometabolic health of US adults from 2009 to August 2023 by income level, and to evaluate pandemic-related shifts.

METHODS: We conducted a serial cross-sectional analysis of National Health and Nutrition Examination Survey participants aged ≥ 18 years (2009-2010 to August 2021-August 2023). Low-income was defined as ≤ 200% of the federal poverty level. We evaluated changes in the age- and sex-adjusted prevalence, treatment, and control of hypertension, diabetes, and high cholesterol, and the prevalence of obesity and smoking, among low- and higher-income adults. Linear regression models estimated pandemic-associated shifts.

RESULTS: Among 62,108 adults (mean age 46.3 years; 51.7% female), the prevalence of hypertension or high cholesterol did not change in either income group. Obesity prevalence rose among low-income adults (37.3% to 42.1%; absolute change +4.8 pp [95% CI, 1.1, 8.5]). Diabetes prevalence increased in both groups (low-income: +5.1 pp [1.4, 8.8]; higher-income: +2.5 pp [0.7, 4.3]), but remained higher among low-income adults (17.6% vs 12.4%; absolute difference +5.2 pp [1.6, 8.8]). While diabetes treatment did not change, an income-related gap in diabetes control emerged: by August 2021-August 2023, 43.0% of low-income adults achieved glycemic control compared to 52.8% of higher-income adults (absolute difference -9.8 pp [-17.5, -2.1]), coinciding with a greater-than-expected decline in diabetes control among low-income adults in the wake of the pandemic (level shift -8.7 pp [-16.7, -0.6]). The income-related gap in hypertension treatment in 2009-2010 had closed by August 2021-August 2023, following a greater-than-expected increase in treatment among low-income adults after the pandemic (level shift +7.8 pp [1.8, 13.8]). High cholesterol treatment and control improved in both groups, with no income-related differences. Smoking declined for both low-income (30.2% to 22.8%, absolute change -7.4 pp [-12.0, -2.8]) and higher-income (15.0% to 10.3%, absolute change -4.7 pp [-7.1, -2.3]) adults, but remained more than two-fold higher in the low-income group.

CONCLUSIONS: Between 2009 and August 2023, there was no improvement in the prevalence of hypertension or high cholesterol. Obesity and diabetes prevalence rose among low-income adults and a new income-related gap in diabetes control emerged, coinciding with a greater-than-expected decline in glycemic control among low-income adults after the pandemic. Targeted efforts are needed to improve risk factor prevention, strengthen glycemic control in low-income populations, and address persistent income-related disparities in cardiometabolic health.

The US health care system relies on international medical graduates, most of whom complete residency or fellowship postgraduate training in the US on J-1 visas. The nation's reliance on J-1 physicians-in-training increased between 2016 and 2024, particularly in regions and specialties facing workforce shortages. Disruptions to J-1 visa processing may therefore affect regions and specialties already facing workforce strain.