Capsule Commentary on Navathe, et al., Do Changes in Post-acute
Care Use at Hospitals Participating in an Accountable Care
Organization Spillover to all Medicare Beneficiaries?
Michael L. Barnett, MD, MS
Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, MA, USA;
Division of General Internal
Medicine and Primary Care, Department of Medicine, Brigham and Women’s Hospital, Boston, MA, USA;
Department of Medicine, Harvard
Medical School, Boston, MA, USA.
J Gen Intern Med 33(6):943
© Society of General Internal Medicine 2018
his careful analysis by Navathe and colleagues
a crucial question in health care policy: how does post-
acute care (PAC) use respond to new payment incentives? The
investigators explored this question in Medicare’saccountable
care organization (ACO) payment model, as implemented in
the Medicare Shared Savings Program (MSSP) from 2012–
2013. Early research has shown that the modest savings
achieved so far in the MSSP have been concentrated in re-
duced PAC spending.
However, a key methodological issue
is that these analyses have focused exclusively on ACO-
In general, only a minority of admitted Medicare patients
will generally be attributed to a hospital’s ACO. Therefore, it
is an open question how hospitals would respond to ACO
incentives affecting some patients but not others. Optimisti-
cally, ACO incentives could spur development of hospital-
wide programs to improve the value of care delivery. On the
other hand, hospitals could instead narrowly focus cost sav-
ings measures on their ACO patients, ignoring others.
Using a robust observational study design to control for
selection bias among patients and hospitals treated in ACOs,
Navathe and colleagues found no evidence that ACO partici-
pation changed the likelihood of patients’ discharge to PAC
vs. control hospitals. There was also little impact in length of
stay for patients discharged to PAC. There were differential
reductions in PAC payments to skilled nursing facilities and
inpatient rehabilitation facilities, but these estimates did not
reach statistical significance.
This important evidence from Navathe and colleagues sup-
ports the concept that the financial incentives in the ACO
program are too weak to generate program-wide changes in
care delivery. Together with evidence of modest savings
among ACO-attributed patients in the MSSP,
imply that hospitals are narrowly responding to ACO incen-
tives to largely target patients they are financially responsible
for. It is probably unrealistic to expect system-wide delivery
reform from payment changes that only affect small slices of
hospitals’ or individual providers’ patients.
Though the ACO
model has promise, this study reinforces that their current
implementation lacks the teeth necessary to create true reform.
Corresponding Author: Michael Barnett, MD, MS; Department of
Health Policy and Management Harvard T.H. Chan School of Public
Health, Boston, MA, USA (e-mail: firstname.lastname@example.org).
Compliance with ethical standards:
Conflict of interest: The author declares that he does not have a
conflict of interest.
1. Navathe AS, Bain AM, Werner RM. Do changes in post-acute care use at
hospitals participating in an accountable care organization spillover to all
Medicare beneficiaries? J Gen Intern Med 2018 https://doi.org/10.1007/
2. McWilliams JM, Hatfield LA, Chernew ME, Landon BE, Schwartz AL.
Early Performance of Accountable Care Organizations in Medicare. N Engl
J Med 2016;374(24):2357–66.
3. McWilliams JM, Gilstrap LG, Stevenson DG, Chernew ME, Huskamp
HA, Grabowski DC. Changes in Postacute Care in the Medicare Shared
Savings Program. JAMA Intern Med 2017
4. McWilliams JM. Changes in Medicare Shared Savings Program Savings
From 2013 to 2014. JAMA 2016;316(16):1711–3.
5. Landon BE. Tipping the Scale — The Norms Hypothesis and Primary Care
Physician Behavior. N Engl J Med 2017;376(9):810–1.
Published online April 9, 2018