Table 3.

Predictors of HIV seroconversion in people who inject drugs in Thessaloniki, Greece from a Cox proportional hazards model (N = 380 initially seronegative participants with at least two available HIV tests).

Variable	Crude Hazard Ratio (95%CI)	p	Adjusted Hazard Ratio (95% CI)	p
Age (per year)	0.98 (0.94–1.03)	0.488	0.99 (0.94–1.04)	0.721
Sex
Female	1
Male	0.77 (0.27–2.23)	0.631	0.60 (0.21–1.77)	0.356
Country of origin
Greece	1
Other	1.21 (0.46–3.18)	0.707
Experiencing homelessnessa
No	1
Yes	3.21 (1.51–6.84)	0.002	2.68 (1.24–5.81)	0.012
Main substance of usea
Heroin	1
Cocaine	1.00 (0.35–2.91)	0.993
Injecting drug use in the past 30 days
No	1
Yes	2.75 (1.04–7.26)	0.041
Frequency of injecting drug usea
Once per day or less
More than once per day	3.13 (1.41–6.97)	0.005
Receptive syringe sharing a,b
No	1		1
Yes	4.50 (2.11–9.62)	<0.001	3.86 (1.75–8.51)	0.001
Use drugs divided with a syringe that someone else had already injected witha
No	1
Yes	4.57 (2.14–9.77)	<0.001

^apast 12 months.

^bincluding using used syringes collected from the street.