Table 3.

Effects of injection behaviors on polysubstance use in multivariate logistic regression.

3a. Polysubstance Use
	OR (95% CI)	p Value
Years injecting *	0.77 [0.46–1.29]	0.313
Inject in the last 30 days	12.67 [1.91–83.74]	0.008
Number of times injected in last 30 days *	1.02 [1.00–1.03]	0.016
Number of days injected in last 30 days *	1.07 [1.02–1.13]	0.007
Number of times using syringe before changing it *	0.84 [0.58–1.22]	0.361
On a regular basis, how many times do you use a syringe? *	0.91 [0.65–1.27]	0.570
Has reduced injection drug use	0.70 [0.23–2.09]	0.519
3b. Polysubstance exclusive of just heroin and cannabis (PSU-EC)
Years injecting *	1.04 [0.54–2.01]	0.896
Inject in the last 30 days	4.27 [0.40–45.67]	0.230
Number of times injected in last 30 days *	1.01 [1.00–1.03]	0.076
Number of days injected in last 30 days *	1.04 [0.98–1.10]	0.224
Number of times using syringe before changing it *	1.18 [0.82–1.70]	0.370
On a regular basis, how many times do you use a syringe? *	1.27 [0.90–1.80]	0.181
Has reduced injection drug use	0.51 [0.17–1.52]	0.228

Note: These are separate multivariate analyses; each analysis has been controlled for age, gender, HIV status, MAT status, location, lifetime history of incarceration, age of first injection, number of other known PWID, and having used a syringe at last injection that was previously used by someone else in order to control for collinearity. OR= odds ratio; CI= confidence interval; * For continuous variables, ORs are for per unit increase in that variable.