high risk sharing behaviors: the effect of sex within injecting partnerships meghan d. morris, phd,...
TRANSCRIPT
High Risk Sharing Behaviors: The Effect of Sex within
Injecting Partnerships
Meghan D. Morris, PhD, MPHPostdoctoral Research Fellow
Department of Epidemiology & BiostatisticsUniversity of California, San Francisco
Acknowledgements
Co-AuthorsJennifer Evans, Michelle Yu, Alya
Briceno, Martha Montgomery, Kimberly Page, Judith Hahn
CollaboratorsPaula Lum, Michael Busch, Eric
Delwart, Leslie ToblerFunding
(NIH-NIDA)R01-DA016017, R01-DA031056, K01-
DA023365The research participants and staff!
Background
• Research has supported the notion that relationships between IDU, rather than individual risk behaviors alone, contribute significantly to the disease transmission patterns in IDU populations.
Few studies have considered both the individual and their injecting partner when identifying factors associated with
drug using behaviors.
• For most young injection drug users (IDU), injecting drugs is a highly social activity.
Study Objectives
• To characterize injecting partnerships within a cohort of young (<30 years) IDU
• To measure the prevalence and estimate partnership characteristics associated with two high risk sharing behaviors: (1) receptive syringe sharing(2) receptive cooker use
Study Hypothesis
1. Female-Male injecting partnerships are at greater odds of high risk sharing behaviors than Male-Male injecting partnerships.
2. Partnerships engaging in both injection and sexual behaviors are at even greater odds of high risk sharing behaviors compared to partnerships engaged in only injecting.
The UFO “Partnership Study”Study Design:
• Prospective study of hepatitis C (HCV) transmission and acquisition within injecting dyads
• Injecting partnerships were interviewed monthly for up to 6 months; with possibility of reenrollment
• San Francisco, CA USA
Injecting Partnership Definition:
1. Injected together ≥ 5x in past month
AND
2. HCV RNA discordant upon enrollment
Eligibility did not require that drugs or injection equipment were shared
HCV+ Index
HCV- Partner
Analytic MethodsStatistical Analysis:
Multilevel Generalized Estimating Equations were used:
– To examine the effect of partnership type on high risk sharing behaviors.
• Egocentric analysis focused on the “at risk” HCV-negative partner
Outcomes:1. Recent Receptive Syringe Sharing
“Within the past 30 days, did you inject with a needle that your partner had already used, even if by accident or mistake?”
2. Recent Receptive Cooker Sharing“Within the past 30 days, was there any time that your partner’s previously used needle had been used with a cooker before you used that cooker?”
Receptive Risk
HCV+ Index
HCV- Partner
28% receptive cooker sharing
17% receptive syringe sharing
Study SampleBaseline Sample
Baseline + Followup Sample
58 “at risk” partners
58 Injecting Partnerships
251 interviews among “at risk” partners
Median of 4 interviews per partnership
9 new HCV infections
85% agreement in reporting of high risk sharing behaviors within partnerships
• Median age 24 (IQR: 22-27)
• Median duration of injection drug use was 6 years (IQR:3-9)
Baseline characteristics of “at risk” partners (n=58)
Ever been in drug
treatment
Ever been in jail/prison
WhiteFemale0
10
20
30
40
50
60
70
80
90
100
Perc
ent (
%)
Baseline Partnership-level Characteristics (n=58)
35%
62%
4%
Gender Composition of Inject-ing Partnerships
Male-Male in-jecting part-nershipMale-Female injecting partnershipFemale-Female injecting part-nership
• 34% of injecting partnerships were engaged in sexual behaviors
• 56% always pooled money to buy drugs
• 80% lived together
• Median duration of injecting partnership was 4 months (IQR:2-12)
• Median time known partner was 10 months (IQR: 4-18)
Bivariate associations with high risk sharing behaviors
Receptive Syringe Sharing(n=251)
Receptive Cooker Sharing(n=251)
OR (95% CI) OR (95% CI)
Male-Female injecting partnership vs. Male-Male injecting partnership
1.8(0.4-7.9)
1.1 (0.4-3.2)
Sex with injection partner in past month 2.8 (1.1-7.6)
2.5 (1.1-6.2)
Age at first injection drug use (per year increase)
0.9(0.9-1.9)
0.9 (1.0-1.3)
Biological Sex is Female vs. Male 1.1(0.3-3.4)
0.8(0.3-2.9)
Known partner for ≥ 1 year vs. <1 year 1.1 (0.5-2.7)
0.6 (0.3-1.4)
*GEE models with link logit, controlling for multiple partnerships
Recent sex with injecting partner independently associated with high risk sharing behaviors
Receptive Syringe Sharing(n=251)
Receptive Cooker Sharing(n=251)
OR (95% CI) AOR (95% CI) OR (95% CI) AOR (95% CI)
Sex with injection partner in past month
2.84 (1.06-7.57)
4.01 (1.30-12.36)
2.50 (1.02-6.17)
4.29 (1.40-13.19)
Age at first injection drug use (per year increase)
0.96(0.91-1.91) ns 0.88 (1.01-
1.29) ns
Biological Sex is Female vs. Male 1.06 (0.33-3.42) ns 0.77 (0.29-
2.91) ns
Known partner for ≥ 1 year vs. <1 year
1.10 (0.45-2.67) ns 0.60 (0.25-
1.41) ns
*GEE models with link logit, controlling for multiple partnershipsAOR=Adjusted Odds Ratio
ns= not significant
A higher proportion of recent high risk sharing behaviors occur within
female-male sex + injecting partnerships
Male-Male In
jecting O
nly Partnersh
ip
Female-Male In
jecting O
nly Partnersh
ip
Female-Male Sexu
al + In
jecting Partn
ership
0%
5%
10%
15%
20%
25%
30%
Receptive Syringe Sharing
Partnership Type
Prev
alen
ce o
f rec
ent R
SS
Male-Male In
jecting O
nly Partnersh
ip
Female-Male In
jecting O
nly Partnersh
ip
Female-Male Sexu
al + In
jecting Partn
ership
0%
5%
10%
15%
20%
25%
30%
Receptive Cooker Use
Partnership Type
Prev
alen
ce o
f rec
ent R
CU
Overall p<0.01Overall p<0.01
Summary
• Sex-composition alone was not significantly associated with an increased odds of high risk sharing behaviors.
• Injecting partnerships engaged in sexual behaviors were at significantly greater odds of both receptive syringe sharing and receptive cooker use.
• For female-male injection partnerships, it appears to be the combination of a sexual and injecting partnership that drives high risk injection behaviors.
Future Directions
Future studies are needed to examine:
• Decision making processes within these injecting partnerships resulting in [or protecting from] high risk sharing behaviors.
• Why some partnerships remain HCV- even though they engage in high risk sharing behaviors with their HCV+ partners.
• Underlying factors influencing high risk sharing behaviors within sexual+injecting partnerships.
Acknowledgements to community collaborators and contributors
• Food Runners • HIV Prevention Project, SF AIDS Foundation• Homeless Youth Alliance• San Francisco Needle Exchange• SFDPH AIDS Office• SFDPH Adult Immunization Clinic• SFDPH Community Health Epidemiology & Disease
Control• SFDPH Housing and Urban Health• Street Outreach Services, SFCCC• Tenderloin Clinical Research Center (TCRC)
THANK YOU!
For more information:Email: [email protected] study: www.ufostudy.org
InC3 Study: InC3.epi-ucsf.org