Table 3.

Results of Multiple Regression Analyses on the Effect of Opioid Substitution Treatment and Highly Active Antiretroviral Therapy on All-Cause and Cause-Specific Mortality

Model Type	Covariate	Categories	All-Cause Mortality	COD: Drug-Related	COD: Human Immunodeficiency Virus–Related	COD: Other
			AHR (95% CI)	AHR (95% CI)	AHR (95% CI)	AHR (95% CI)
Subdistribution PH model 1a	OST	Yes vs no	0.20 (.15, .26)	0.65 (.39, 1.09)	0.20 (.14, .30)	0.26 (.15, .45)
	HAART	Yes vs no	0.29 (.24, .35)	0.54 (.35, .84)	0.31 (.24, .40)	0.50 (.34, .74)
Subdistribution PH model 2a	OST and HAART	Off OST and HAART	Ref	Ref	Ref	Ref
		On OST only	0.18 (.13, .25)	0.60 (.32, 1.12)	0.21 (.13, .35)	0.30 (.15, .59)
		On HAART only	0.29 (.23, .36)	0.49 (.28, .87)	0.31 (.23, .42)	0.54 (.35, .81)
		On OST and HAART	0.07 (.05, .09)	0.37 (.20, .70)	0.06 (.04, .11)	0.11 (.05, .25)
Marginal Structural Model 1b,c	OST	Yes vs no	0.34 (.23, .49)	0.68 (.42, 1.12)	0.33 (.23, .48)	0.19 (.12, .32)
Marginal Structural Model 2b,d	HAART	Yes vs no	0.39 (.31, .48)	0.49 (.32, .75)	0.34 (.26, .44)	0.42 (.29, .60)
Marginal Structural Model 3b	OST and HAART	Off OST and HAART	Ref	Ref	Ref	Ref
		On OST only	0.34 (.22, .52)	0.45 (.22, .92)	0.35 (.21, .56)	0.23 (.10, .52)
		On HAART only	0.46 (.34, .62)	0.37 (.21, .64)	0.35 (.26, .46)	0.64 (.46, .90)
		On OST and HAART	0.16 (.10, .26)	0.40 (.22, .73)	0.14 (.08, .23)	0.08 (.04, .17)

Abbreviations: AHR, adjusted hazard ratio; CI, confidence interval; COD, cause of death; HAART, highly active antiretroviral therapy; OST, opioid substitution treatment; PH, proportional hazards; Ref, reference.

^a Data are organized into durations on and off OST and HAART.

^b Data are organized in monthly intervals; OST and HAART receipt in at least 95% of days in a given month; estimated parameters are cause-specific hazard ratios.

^c HAART is included as a time-dependent confounder in the model.

^d OST is included as a time-dependent confounder in the model.