Table 2.

Log-linear GEE regression: cost of care associated with the joint diagnoses of substance use disorder (SU) and psychiatric disease (PD), adjusted for demographic and clinical characteristics in HIV-infected patients receiving care at the KPNC health plan.

Outcome	Diagnosis	Unadjusted OR (95% C.I.)	Partially adjusted∗ OR (95% C.I.)	Fully adjusted∗∗ OR (95% C.I.)
		Model 1	Model 2	Model 3
Total costs	Both PD and SU diagnoses	1.53 (1.46, 1.60)	1.35 (1.29, 1.42)	1.35 (1.29, 1.42)
	PD diagnosis only	1.34 (1.29, 1.40)	1.21 (1.16, 1.26)	1.19 (1.15, 1.24)
	SU diagnosis only	1.35 (1.28, 1.42)	1.26 (1.20, 1.33)	1.24 (1.18, 1.31)
	Neither PD nor SU diagnosis	1.00 (ref)	1.00 (ref)	1.00 (ref)
Inpatient costs	Both PD and SU diagnoses	1.29 (1.11, 1.50)	1.67 (1.42, 1.97)	2.22 (1.85, 2.66)
	PD diagnosis only	1.03 (0.88, 1.21)	1.17 (0.98, 1.38)	1.28 (1.11, 1.49)
	SU diagnosis only	1.74 (1.49, 2.02)	1.92 (1.63, 2.27)	2.14 (1.78, 2.58)
	Neither PD nor SU diagnosis	1.00 (ref)	1.00 (ref)	1.00 (ref)
Outpatient costs	Both PD and SU diagnoses	1.48 (1.36, 1.61)	1.55 (1.43, 1.67)	1.52 (1.41, 1.64)
	PD diagnosis only	1.24 (1.16, 1.32)	1.28 (1.20, 1.36)	1.28 (1.20, 1.37)
	SU diagnosis only	1.26 (1.17, 1.37)	1.28 (1.19, 1.37)	1.27 (1.17, 1.38)
	Neither PD nor SU diagnosis	1.00 (ref)	1.00 (ref)	1.00 (ref)
Pharmacy costs	Both PD and SU diagnoses	2.32 (2.24, 2.40)	1.16 (1.11, 1.21)	1.10 (1.06, 1.14)
	PD diagnosis only	1.75 (1.70, 1.81)	1.13 (1.09, 1.17)	1.08 (1.04, 1.10)
	SU diagnosis only	1.65 (1.60, 1.71)	1.10 (1.07, 1.14)	1.06 (1.03, 1.09)
	Neither PD nor SU diagnosis	1.00 (ref)	1.00 (ref)	1.00 (ref)

*Adjusted for age at time when cost occurred, year when costs occurred, sex, and race/ethnicity.

∗∗Adjusted for age, year when costs occurred, sex, race/ethnicity, HIV transmission risk group, HIV RNA level, and CD4+ cell count (both time-dependent).