Table 2. Differential Change in Practice Patterns for PE- and Non−PE-Acquired Physician Practices^a.

Variables	PE-acquired practices		Controls		Unadjusted	Adjusted
	Before	After	Before	After	DiD	DiD	% (95% CI)	P value
Allowed amount/claim, $	206.0	285.0	201.0	260.0	20.0	22.8	11.0 (5.6 to 16.5)	<.001
Utilization
Unique patient	105.0	147.0	93.0	108.0	27.0	27.1	25.8 (15.8 to 35.6)	<.001
New patient	57.0	89.0	47.0	57.0	22.0	21.6	37.9 (25.6 to 50.2)	<.001
Practice patterns
Charge/claim, $	353.0	514.0	372.0	474.0	59.0	71.4	20.2 (13.1 to 27.3)	<.001
Patient HCC score	1.2	1.3	1.4	1.5	–0.1	0.01	1.0 (–2.4 to 4.8)	.64
E&M visit >30 min
Established patient, %	0.2	0.2	0.2	0.2	0.0	0.01	9.4 (1.7 to 17.0)	.03
New patient, %	0.3	0.3	0.3	0.3	0.0	0.02	5.8 (–3.2 to 14.8)	.21
E&M visit	86.3	115.7	77.0	90.2	16.0	32.0	37.1 (–48.5 to 122.5)	.40
Encounters	138.1	191.1	123.8	143.5	33.0	91.0	16.3 (1.0 to 32.0)	.04

Abbreviations: DiD, difference in differences; E&M, evaluation and management; HCC, Hierarchical Condition Category; PE, private equity.

^a Unadjusted and adjusted differential changes in outcome variables averaged at the practice level for PE practices and matched controls. Adjusted regression coefficients were estimated using a linear DiD model that included specialty fixed-effects and was weighted by average patient volume per practice over the study period. Standard errors were clustered at the level of the matched cohort. Regressions with measures of patient volume as dependent variables (ie, total No. of unique patients and new patients) are unweighted. Adjusted percentage differential change was calculated by dividing the adjusted differential change obtained from the DiD regression, by the preacquisition mean for PE-acquired practices. DiD are between PE-acquired practices and controls or the differential change.