Table 4. Adjusted Relationship Between Network Characteristics and Medicare Spending, Utilization, and Quality (All Measures Entered into a Single Model).

Variable	Mean, $	Difference
		Adjusted Degree	P Value	Physician Dispersion	P Value	PCP, %	P Value
Total spending, $	10 051	1086	<.001	−192	<.001	−62	.33
Spending by category, $
Hospital inpatient	3533	77	<.001	−15	<.001	−	<.001
Physician	2874	201	<.001	−24	.02	−6	.65
Hospital outpatient department	3526	421	<.001	−81	<.001	−29	.60
Skilled nursing facility
Hospice	118	1	.14	−2	.04	0	.87
Utilization of services (per patient)
Admissions	0.38	0.02	<.001	0	.03	0	.87
Hospital days	2.48	0.17	<.001	0.03	.03	−0.02	.42
PCP Office visits	5.53	0.13	.001	−0.07	.02	0.44	<.001
Specialty office visits	6.50	0.38	<.001	−0.04	.07	−0.33	<.001
Emergency department visits	0.64	0.02	<.001	−0.01	<.001	−0.01	.05
Quality of care
Any 30-day readmission, %	18.3	0.5	<.001	−0.04	.61	−0.10	.09
Acute PQI (per 100)	2.4	0.1	.001	0.1	<.001	0.01	.46
Chronic PQI (per 100)	2.9	0.1	<.001	0.1	.003	0.10	.01
Mammography, %	47.3	−0.7	.001	−2.2	<.001	−1.9	<.001
Diabetes
LDL cholesterol testing, %	83.1	−2.1	.06	−0.3	.74	0.05	.96
Hemoglobin A1c testing, %	88.0	−1.8	.15	−0.4	.68	−4.6	<.001
Retinal examination, %	60.3	1.8	<.001	−3.0	<.001	−2.2	<.001
All 3 services, %	49.4	1.1	.04	−2.2	<.001	−1.3	<.001
Cardiovascular disease
LDL testing, %	79.4	−3.6	<.001	−1.6	.02	2.0	.02

Abbreviations: LDL, low-density lipoprotein; PCP, primary care physician; PQI, Prevention Quality Indicators.