Proportion of Racial Minority Patients and Patients With Low Socioeconomic Status Cared for by Physician Groups After Joining Accountable Care Organizations

Jessica T Lee,Daniel Polsky,Robert Fitzsimmons,Rachel M Werner

doi:10.1001/jamanetworkopen.2020.4439

Jessica T Lee, Daniel Polsky + Show 2 more

Open Access

https://doi.org/10.1001/jamanetworkopen.2020.4439

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Abstract

The incentive structure of accountable care organizations (ACOs) may lead to participating physician groups selecting fewer vulnerable patients. To test for changes in the percentage of racial minority patients and patients with low socioeconomic status cared for by physician groups after joining the ACO. This retrospective cohort consisted of a 15% random sample of Medicare fee-for-service beneficiaries attributed to physician groups from 2010 to 2016. Medicare Shared Savings Program (MSSP) participation was determined using ACO files. Analyses were conducted between January 1, 2019, and February 25, 2020. Using linear probability models, we conducted difference-in-differences analyses based on the year a physician group joined an ACO to estimate changes in vulnerable patients within ACO-participating groups compared with nonparticipating groups. Whether the patient was black, was dually enrolled in Medicare and Medicaid, and poverty and unemployment rates of the patient's zip code. In a cohort of 76 717 physician groups caring for 7 307 130 patients, 16.1% of groups caring for 27.8% of patients participated in an MSSP ACO. Using 2010 characteristics, patients attributed to ACOs from 2012 to 2016, compared with those who were not, were less likely to be black (8.0% [n = 81 698] vs 9.3% [n = 270 924]) or dually enrolled in Medicare and Medicaid (12.8% [n = 130 957] vs 18.2% [n = 528 685]), and lived in zip codes with lower poverty rates (13.8% vs 15.5%); unemployment rates were similar (8.0% vs 8.5%). In the difference-in-differences analysis, there was no statistically significant change associated with ACO participation in the proportions of vulnerable patients attributed to ACO-participating groups compared with nonparticipating groups. After joining an ACO, ACO-participating groups had 0.0 percentage points change (95% CI, -0.1 to 0.1 percentage points; P = .59) for black patients, -0.1 percentage points (95% CI, -0.2 to 0.1 percentage points; P = .32) for patients dually enrolled in Medicare and Medicaid, 0.2 percentage points (95% CI, -3.5 to 4.0 percentage points; P = .91) in poverty rates, and -0.4 percentage points (95% CI, -2.0 to 1.2 percentage points; P = .62) in unemployment rates. In this cohort study, there were no changes in the proportions of vulnerable patients cared for by ACO-participating physician groups after joining an ACO compared with changes among nonparticipating groups.

Highlights

Accountable care organizations (ACOs) are the largest experimentation with payment reforms in the United States, with more than 1000 ACOs covering more than 32 million patients in 2018.1 Accountable care organizations are networks of clinicians responsible for managing the cost and quality of care for a defined population of patients across the continuum of health care settings
In a cohort of 76 717 physician groups caring for 7 307 130 patients, 16.1% of groups caring for 27.8% of patients participated in an Medicare Shared Savings Program (MSSP) ACO
In the difference-in-differences analysis, there was no statistically significant change associated with ACO participation in the proportions of vulnerable patients attributed to ACO-participating groups compared with nonparticipating groups

Summary

Introduction

Accountable care organizations (ACOs) are the largest experimentation with payment reforms in the United States, with more than 1000 ACOs covering more than 32 million patients in 2018.1 Accountable care organizations are networks of clinicians responsible for managing the cost and quality of care for a defined population of patients across the continuum of health care settings. The largest ACO program in the country is the Medicare Shared Savings Program (MSSP). Evidence has shown ACOs have been successful in improving the quality of care and reducing costs in some cases,[3,4,5,6,7,8,9,10,11] with nearly $800 million in shared savings reported within the MSSP in 2017.2 Despite these successes, there are concerns that ACOs may reinforce or potentially exacerbate disparities in health care quality, by providing incentives that lead physician groups to avoid the highest-cost and most vulnerable patients.[12,13] Prior research has demonstrated that ACOs typically form in geographic areas with fewer black residents and lower rates of poverty, fewer uninsured patients, and fewer patients without high school education.[14,15] ACOs that care for a higher proportion of minority patients have lower performance quality metrics.[16] the evidence that ACOs avoid vulnerable patients is inconsistent. Work has demonstrated that compared with nonparticipating groups, physician groups participating in the MSSP took care of a similar proportion of patients who are racial minorities, dually enrolled in Medicare and Medicaid, or living in a high-poverty zip code[17] and that ACOs with a high proportion of minority patients are committed to the mission of MSSP.[18]

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