By Adam A. Markovitz, BS; John M. Hollingsworth, MD, MS; John Z. Ayanian, MD, MPP; Edward C. Norton, PhD; Phyllis L. Yan, MS; Andrew M. Ryan, PhD
Annals of Internal Medicine, June 18, 2019
Accountable care organizations (ACOs) in the Medicare Shared Savings Program (MSSP) are associated with modest savings. However, prior research may overstate this effect if high-cost clinicians exit ACOs.
To evaluate the effect of the MSSP on spending and quality while accounting for clinicians’ nonrandom exit.
Similar to prior MSSP analyses, this study compared MSSP ACO participants versus control beneficiaries using adjusted longitudinal models that accounted for secular trends, market factors, and beneficiary characteristics. To further account for selection effects, the share of nearby clinicians in the MSSP was used as an instrumental variable. Hip fracture served as a falsification outcome. The authors also tested for compositional changes among MSSP participants.
Fee-for-service Medicare, 2008 through 2014.
A 20% sample (97 204 192 beneficiary-quarters).
Total spending, 4 quality indicators, and hospitalization for hip fracture.
In adjusted longitudinal models, the MSSP was associated with spending reductions (change, −$118 [95% CI, −$151 to −$85] per beneficiary-quarter) and improvements in all 4 quality indicators. In instrumental variable models, the MSSP was not associated with spending (change, $5 [CI, −$51 to $62] per beneficiary-quarter) or quality. In falsification tests, the MSSP was associated with hip fracture in the adjusted model (−0.24 hospitalizations for hip fracture [CI, −0.32 to −0.16 hospitalizations] per 1000 beneficiary-quarters) but not in the instrumental variable model (0.05 hospitalizations [CI, −0.10 to 0.20 hospitalizations] per 1000 beneficiary-quarters). Compositional changes were driven by high-cost clinicians exiting ACOs: High-cost clinicians (99th percentile) had a 30.4% chance of exiting the MSSP, compared with a 13.8% chance among median-cost clinicians (50th percentile).
The study used an observational design and administrative data.
After adjustment for clinicians’ nonrandom exit, the MSSP was not associated with improvements in spending or quality. Selection effects — including exit of high-cost clinicians — may drive estimates of savings in the MSSP.
Primary Funding Source:
Horowitz Foundation for Social Policy, Agency for Healthcare Research and Quality, and National Institute on Aging.
Spending Reductions in the Medicare Shared Savings Program: Selection or Savings?
By J. Michael McWilliams, MD, PhD, Alan M. Zaslavsky, PhD, Bruce E. Landon, MD, MBA, and Michael E. Chernew, PhD
The Incidental Economist, June 17, 2019
Prior studies suggest that accountable care organizations (ACOs) in the MSSP have achieved modest, growing savings. In a recent study in Annals of Internal Medicine, Markovitz et al. conclude that savings from the MSSP are illusory, an artifact of risk selection behaviors by ACOs such as “pruning” primary care physicians (PCPs) with high-cost patients. Their conclusions appear to contradict previous findings that characteristics of ACO patients changed minimally over time relative to local control groups.
Monitoring ACOs will be essential, particularly as incentives for selection are strengthened as regional spending rates become increasingly important in determining benchmarks. Although there has likely been some gaming, the evidence to date — including the study by Markovitz et al. — provides no clear evidence of a costly problem and suggests that ACOs have achieved very small, but real, savings. Causal inference is hard but necessary to inform policy. When conclusions differ, opportunities arise to understand methodological differences and to clarify their implications for policy.
By Don McCanne, M.D.
This important study in the highly reputable Annals of Internal Medicine concludes that accountable care organizations (ACOs) participating in the Medicare Shared Savings Program (MSSP) did not show any improvement in spending or quality when adjustments were made for selection effects, especially the non-random exit of high-cost clinicians (“I’m worth the extra money, and if you’re gonna cut my fees, I’m outta here.”)
The conclusions were immediately challenged by others in the policy community who have previously published studies indicating that “ACOs have achieved very small, but real, savings,” albeit admitting that “there has likely been some gaming.” And the savings were, indeed, very small. Others have suggested that the very small savings did not take into consideration the significant increase in provider administrative costs for technological equipment and personnel to run the ACOs, and certainly did not consider other unintended consequences such as the tragic increase in physician burnout.
Another problem with the infatuation for ACOs is that politicians and the policy community are insisting that we continue with this experiment in spite of the disappointing results to date. That simply postpones the adoption of truly effective policies, such as those in a single payer Medicare for All program, that would actually improve quality while greatly reducing administrative waste. The tragedy is that this also perpetuates uninsurance, underinsurance, and personal financial hardship from medical bills.
People are suffering and dying while the policy community continues to diddle with ACOs and other injudicious policy inventions. Enough! It’s long past time to reduce suffering and save lives! Single Payer Medicare for All!
(Yes, I’m angry, but even more I’m terribly anguished over the health care injustices that we continue to tolerate through our collective inaction.)
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