Table 4.

Mean annual costs (5/02-4/03) by RxRisk quartile^* (Lower quartile = fewer comorbidities)

RxRisk Quartile	Cost Category	No. Cases	Mean ($)	No. Controls	Mean ($)	p-value
I	Pharmacy	62	1244	238	431	<0.0001
	Outpatient		2015		950	<0.0001
	Inpatient		947		528	0.506
	Total		4206		1909	0.008
II	Pharmacy	60	1515	247	544	<0.0001
	Outpatient		2348		1212	<0.0001
	Inpatient		2496		313	0.003
	Total		6359		2070	<0.0001
III	Pharmacy	58	2074	137	1266	0.004
	Outpatient		3176		1320	<0.0001
	Inpatient		1418		1441	0.984
	Total		6667		4028	0.073
IV	Pharmacy	43	3720	95	3101	0.349
	Outpatient		4053		2655	0.030
	Inpatient		2934		1077	0.091
	Total		10,707		6832	0.023

^*RxRisk score based on comorbidities in prior year.