TABLE 2.

Unadjusted Costs, Within Group Adjusted* Cost Ratios, and Adjusted* Difference in Differences Cost Ratios at 3 and 12 Months After Initiation of Treatment by Treatment Category

		Unadjusted Mean Cost Per Member Per Month [Mean (SD)] ($)
Initial Treatment Pathway	n	Baseline	Follow-up	Within Group Adjusted* Cost Ratio†	Adjusted* Difference in Differences Cost Ratio (ADIDCR)‡
3 mo follow-up (n=40,885)
No treatment	2116	2306 (6845)	5250 (22,145)	2.74 (2.26–3.32)	1.00 (Reference)
Inpatient/Detox	6455	2243 (5740)	9222 (14,228)	6.31 (5.89–6.76)	2.30 (1.88–2.83)
Behavioral health intensive outpatient	1970	3148 (5809)	5943 (8936)	2.48 (2.26–2.73)	0.91 (0.73–1.12)
Buprenorphine/methadone	5123	1494 (4065)	2096 (5118)	1.77 (1.63–1.92)	0.65 (0.52–0.80)
Naltrexone	963	4219 (7265)	4960 (7458)	1.46 (1.29–1.66)	0.53 (0.42–0.67)
Behavioral health outpatient	24,258	3940 (9004)	4472 (10,918)	1.48 (1.42–1.55)	0.54 (0.44–0.66)
12 mo follow-up (n=21,200)
No treatment	1017	2196 (6079)	2747 (9018)	1.58 (1.27–1.97)	1.00
Inpatient/Detox	3138	2118 (5163)	4534 (6580)	2.92 (2.64–3.22)	1.84 (1.45–2.34)
Behavioral health intensive outpatient	1013	3066 (5494)	3344 (5536)	1.35 (1.18–1.55)	0.85 (0.66–1.10)
Buprenorphine/methadone	2368	1466 (3737)	1972 (3375)	1.62 (1.45–1.81)	1.02 (0.80–1.31)
Naltrexone	443	3966 (7025)	3162 (5753)	0.98 (0.81–1.20)	0.62 (0.46–0.83)
Behavioral health outpatient	13,221	3649 (8297)	3158 (5687)	1.14 (1.09–1.19)	0.72 (0.58–0.90)

*Adjusted for: age, sex, race, insurance type, baseline medical (modified Elixhauser) and mental health comorbidities (depression, anxiety, PTSD, ADHD), and evidence of overdose or infections related to injection drug use at baseline.

^†Ratio of per member per month costs in follow-up to baseline within each treatment pathway.

^‡Difference in differences estimate of total costs of care from baseline to follow-up for each treatment pathway compared with no treatment.

ADHD indicates attention deficit hyperactivity disorder; PTSD, post traumatic stress disorder.