Study Finds ACOs Have No Meaningful Impact on Medication Use or Adherence

Many accountable care organizations (ACOs) participating in the Medicare Shared Savings Program (MSSP) focus on disease control and medication use, but a new study published in JAMA Cardiology has found that the programs have not made any meaningful changes in medication use or adherence.

Researchers analyzed data from Medicare claims and enrollment files from 2009 to 2014 and assessed the proportion of days covered for 6 drug classes: statins, angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, β-blockers, thiazide diuretics, calcium channel blockers, and metformin.

They compared changes in medication use and adherence for Medicare beneficiaries attributed to ACOs from before the ACO contract to after the contract. The authors identified 2009 to 2011 as the precontract period for ACOs that entered MSSP in 2012, 2009 to 2012 as the precontract period for ACOs that entered in 2013, and 2009 to 2013 as the precontract period for ACOs entering in 2014.

Largely, the authors saw no changes among medication use or proportion of days covered. The only significant change in medication use that the authors noted was an increase in the use of thiazides among beneficiaries with hypertension in the 2013 entry cohort. The only change in proportion of days covered was a slight increase for β-blockers in the 2012 entry cohort and for metformin in the 2012 and 2013 cohorts.

“Our findings suggest that incentives in the MSSP to improve disease control and lower hospitalization rates and nondrug spending for patients with cardiovascular disease and diabetes have not been associated with meaningful increase in medication use and adherence,” the authors concluded.

However, they did note that ACOs could have been achieving improvements in disease control through lifestyle modifications or bariatric surgery instead of through pharmacologic means and that there could have been efforts to reduce medication use.

“… it is possible that efforts to limit polypharmacy resulted in appropriate reductions in prescriptions for ACO patients that obscured beneficial increases in use and adherence in our estimation of mean net effects,” the authors wrote.