Hospital-physician integration and clinical volume in traditional Medicare

To test the effect of hospital-physician integration on primary care physicians' (PCP) clinical volume in traditional Medicare.

Nationwide retrospective longitudinal study using Medicare claims and other data sources from 2010 to 2016.

We identified 70,000 PCPs, some of whom remained non-integrated and some who became hospital-integrated during this study period. We used an event study design to identify the effect of integration on key measures of physicians' clinical volume, including the number of claims, work-relative value units (RVUs), professional revenue generated, number of patients treated, and facility fee revenue generated.

Per-physician clinical volume declined by statistically and economically significant margins. Relative to the comparison group who remained non-integrated, work RVUs fell by 7% (95% confidence interval [CI]: -8.6% to -5.5%); the number of patients treated fell by 4% (95% CI: -5.8% to -2.6%); and claims volume among PCPs who became hospital-integrated fell by over 15% (95% CI: -16.8% to -13.5%). Though professional revenue declined by $29,165 (95% CI: -$32,286 to -$26,044), this loss was almost entirely offset by increased facility fee revenue of $28,556 (95% CI: 26,909 to 30,203).

Hospital-physician integration may affect the quantity of clinical services delivered by PCPs to traditional Medicare beneficiaries. Reductions in clinical volume associated with integration may have long-term consequences for the supply of physician services and patient access to primary care. Future research on physician time use and patient access following hospital integration would further add to the evidence base.