Pennsylvania's Medical Home Initiative: Reductions in Healthcare Utilization and Cost Among Medicaid Patients with Medicaland Psychiatric Comorbidities.

Background: The Chronic Care Initiative (CCI) was a large state-wide patient-centered medical home (PCMH) initiative in Pennsylvania in place from 2008-2011.

Objective: Determine whether the CCI impacted the utilization and costs for Medicaid patients with chronic medical conditions and comorbid psychiatric or substance use disorders.

Design: Analysis of Medicaid claims using difference-in-difference regression analyses to compare changes in utilization and costs for patients treated at CCI practices to propensity score-matched patients treated at comparison non-CCI practices.

Setting: Ninety-six CCI practices in Pennsylvania and 60 non-CCI practices during the same time period.

Participants: A total of 11,105 comorbid Medicaid patients treated in CCI practices and an equal number of propensity-matched comparison patients treated in non-CCI practices.

Measurements: Changes in total per-patient costs from 1 year prior to 1 year following an index episode period. Secondary outcomes included utilization and costs for emergency department (ED), inpatient, and outpatient services.

Results: The CCI group experienced an average adjusted total cost savings of $4145.28 per patient per year (P = 0.023) for the CCI relative to the non-CCI group. This was largely driven by a $3521.15 savings (P = 0.046) in inpatient medical costs, in addition to relative savings in outpatient psychiatric ($21.54, P < 0.001) and substance abuse service costs ($16.42, P = 0.013), compared to the non-CCI group. The CCI group, related to the non-CCI group, had decreases in expected mean counts of ED visits (for those who had any) and psychiatric hospitalizations of 15.6 (95 % CI: -21, -9) and 40.7 (95 % CI: -57, -18) percentage points respectively.

Limitations: We do not measure quality of care and cannot make conclusions about the overall cost-effectiveness or long-term effects of the CCI.

Conclusions: The CCI was associated with substantial cost savings, attributable primarily to reduced inpatient costs, among a high-risk group of Medicaid patients, who may disproportionally benefit from care management in patient-centered medical homes.