Table 4.

Comparison of Adjusted Costs (dollars per patient per month) Over 12 and 21 Months at Medical Home Prototype and 19 Other Group Health Clinics

Patient care costsa	Interval	PCMH prototype (n = 1,947)	Other clinics (n = 39,396)	Cost difference	p Value
Primary care	12 Month	$82 ($80, $85)	$80 ($79, $81)	$2.18 ($−0.51, $4.86)	.112
	21 Month	$82 ($79, $84)	$80 ($79, $81)	$1.46 ($−1.20, $4.12)	.283
Specialty care	12 Month	$181 ($169, $193)	$158 ($155, $161)	$22.74 ($10.87, $34.61)	<.001
	21 Month	$183 ($173, $193)	$164 ($162, $166)	$18.82 ($8.90, $28.75)	<.001
Emergency department and urgent care	12 Month	$27 ($24, $29)	$27 ($27, $28)	$−0.76 ($−3.18, $1.66)	.537
	21 Month	$31 ($28, $34)	$32 ($31, $33)	$−1.13 ($−4.07, $1.82)	.454
Inpatient admissions (all cause)	12 Month	$227 ($198, $255)	$253 ($239, $267)	$−26.18 ($−52.86, $0.50)	.054
	21 Month	$261 ($232, $291)	$278 ($267, $289)	$−17.08 ($−46.84, $12.70)	.261
Total costs	12 Month	$806 ($765, $846)	$803 ($787, $819)	$2.79 ($−37.33, $42.91)	.892
	21 Month	$849 ($807, $890)	$854 ($841, $868)	$−5.92 ($−47.61, $35.78)	.781

Notes: PCMH = patient-centered medical home. Adjusted costs estimated from generalized linear models run using an identity link, gamma error, and adjusting for age, gender, and baseline costs (2006).

^aCosts represent per patient per month nominal costs for patient care incurred at Group Health facilities and from external claims. Costs exclude those not directly related to providing health services and patient out-of-pocket costs. Costs annualized for those patients not enrolled for entire year. Costs reported as 2005 inflation-adjusted U.S. dollars using the local medical price index from the U.S. Bureau of Labor Statistics.