Appendix Table 5.

Multivariable-Adjusted Proportions of Utilization, by Clinician Type, in Physician Offices (NAMCS)^*

Variable	Physician (Reference) (n = 12 170)	Nurse Practitioner Only (n = 70)	P Value	Nurse Practitioner and Physician (n = 103)	P Value	Physician Assistant Only (n = 82)	P Value	Physician Assistant and Physician (n = 218)	P Value
Antibiotics	49.2	46.8	0.78	27.3	0.034	56.5	0.51	59.1	0.101
CT/MRI	5.7	0	NA	7.7	0.66	2.2	0.140	2.2	0.163
Radiography	9.8	10.1	0.95	6.5	0.34	12.6	0.56	7.6	0.52
Referral to other physician	7.4	8.2	0.83	8.5	0.74	6.8	0.88	0	0.62

CT = computed tomography; MRI = magnetic resonance imaging; NA = not available; NAMCS = National Ambulatory Medical Care Survey.

^*Values are percentages. Proportions may not match percentages because the percentages represent national estimates based on population weighting. Boldface values indicate comparisons with P < 0.05.