HIV, HIV Infections
Conditions
Keywords
HIV, Injection drug users, Female sex workers, STIs, HIV Seronegativity
Brief summary
The investigators propose a highly efficient four-arm (factorial) trial to simultaneously test the efficacy of two behavioral interventions aimed at: * increasing condom use in the context of ongoing drug use and * decreasing needle and paraphernalia sharing among female sex workers who also inject drugs in two Mexican-U.S. border cities: Tijuana and Ciudad Juarez.
Detailed description
Our specific aims are: * Aim 1: To evaluate the efficacy of a behavioral intervention to decrease sharing of syringes and injection paraphernalia among FSW-IDUs. We hypothesize that FSW-IDUs in the active experimental injection risk reduction condition will report: (a) less receptive and distributive needle sharing; (b) less sharing of injection paraphernalia; (c) obtaining syringes and injection paraphernalia from safer sources. * Aim 2: To evaluate the efficacy of a behavioral intervention to increase condom use among FSW-IDUs in the context of ongoing drug use. We hypothesize that FSW-IDUs in the active experimental sexual risk reduction condition will: (a) report less unprotected vaginal and anal sex; and (b) have fewer incident cases of specific STIs. * Aim 3: To evaluate the joint effects of these two behavioral interventions to increase condom use and reduce sharing of needles and syringes/injection paraphernalia among FSW-IDUs. We hypothesize that the joint effect of these interventions will generate greater risk reductions compared to either intervention alone. * Aim 4: To determine the extent to which theoretically-important components of our interventions (i.e., self-efficacy, outcome expectancies, attitudes, intentions) represent underlying mechanisms of change in primary outcomes (i.e., sexual- and injection-related risk reductions). * Aim 5: To explore subgroup differences in the efficacy of: a) the sexual risk reduction, and b) the injection risk reduction intervention based on background characteristics, contextual factors, social factors and intrapersonal factors.
Interventions
BEHAVIORALInteractive injection and sexual risk intervention
This is a one-on-one intervention that incorporates elements of motivational interviewing (MI) and principles of Social Cognitive Theory (SCT) and Theory of Reasoned Action (TRA) to address the context of both, a) unsafe injection sharing and the extent to which syringes and other injection paraphernalia is shared; and b) unsafe sex and condom use with clients, and associated risks (e.g., HIV (Human Immuno-deficiency Virus), STIs (Sexually Transmitted Infections), pregnancy).
BEHAVIORALInteractive Sexual Risk Intervention
This is a one-on-one intervention that incorporates elements of motivational interviewing (MI) and principles of Social Cognitive Theory (SCT) and Theory of Reasoned Action (TRA) to address the context of unsafe sex and condom use with clients, and associated risks (e.g., HIV (Human Immuno-deficiency Virus), STIs (Sexually Transmitted Infections), pregnancy).
BEHAVIORALInteractive Injection Risk Intervention
This is a one-on-one intervention that incorporates elements of motivational interviewing (MI) and principles of Social Cognitive Theory (SCT) and Theory of Reasoned Action (TRA) to address the context of unsafe injection sharing and the extent to which syringes and other injection paraphernalia is shared.
BEHAVIORALLecture-format presentation
60 minute lecture-format presentation on safer sex and safer injection based on CDC guidelines for HIV counseling, testing, and referral and materials from Mexico's National Center for AIDS Studies (CENSIDA). There are no theory-driven active skill building elements oriented towards safer sex or safer injection.
Sponsors
National Institute on Drug Abuse (NIDA)
University of California, San Diego
ISSESALUD
Universidad Autonoma de Ciudad Juarez
Northeastern University
San Diego State University
University of California, Los Angeles
Steffanie Strathdee
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* be biologically female * be at least 18 years old * report having exchanged sex for money, goods or drugs within the last month * report having injected drugs within the last month * report having unprotected vaginal or anal sex at least once in last 30 days * report sharing needles/syringes or other injection paraphernalia (i.e., cottons, cookers, water) at least once in the last month * live in Tijuana, Ciudad Juarez or its suburbs, as determined through municipal boundaries in each city * test HIV-negative at baseline * agree to receive antibiotic treatment for chlamydia, gonorrhea, syphilis trichomonas vaginalis or bacterial vaginosis if they test positive at baseline.
Exclusion criteria
If women report: * consistent use of condoms for vaginal and anal sex with all male partners during the previous month * not being able to provide verification of injection drug use (i.e. track marks) * not sharing needles/syringes or paraphernalia at least once in the last month * being under 18 years of age * being male or transgender * being incapable of giving informed consent * planning to permanently move outside of the municipal boundaries of Tijuana or Ciudad Juarez within the next year.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis. | 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline | Combined incidence for HIV/STI was calculated over the 12-month study period and included only those who a) had at least one follow-up visit and b) at baseline tested negative for HIV and any of the aforementioned STIs. In the calculations we accounted for the time each participant spent at risk of HIV/any STI during the follow-up period, by using available information on each participant for each time point (i.e. baseline, 4-, 8-, and 12-months was used). The analytic method used for this outcome analysis was Poisson regression with robust variance estimation. The outcome variable was a binary variable indicating whether a participant has contracted HIV or a new STI during the 12-month follow-up period. The primary factor of interest was the intervention group. The log (time spent at risk of HIV/any STI) was used as an offset variable in order to account for the time spent at risk of HIV/any STI by each participant. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline | The analytic method used for a) was negative binomial regression with the number of unprotected sex acts with clients as the outcome variable and intervention group, time point (baseline, 4-, 8-, and 12-months), and the interaction between the two as the main effects of interest. |
| Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline | For a) we asked: In the past month, how often have you used a needle or syringe that you knew or suspected had been used before by someone else? (possible responses: 1=never, 2=sometimes, 3=about half the time, 4=often, 5=always), with a higher response indicating a higher risk. The intervention effect was evaluated by conducting ordinal logistic regression, with the frequency of receptive needle sharing as the outcome variable and Group (Intervention vs. Control), Visit (Baseline, 4-months, 8-months, and 12-months) and the interaction term between the two (Visit\*Group) as the main effects. Our primary interest was the Visit\*Group interaction, with a significant corresponding p-value being indicative of an intervention effect. |
| Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline | The injection risk index (IRI) was calculated by averaging the responses to the following five questions: 1. In the past month, how often have you used a needle or syringe that you knew or suspected had been used before by someone else? 2. In the past month, how often was a new syringe used to divide the drug? 3. In the past month, how often did you use a bottle-cap/spoon/cooker after someone else had used it? 4. In the past month, how often did you use a cotton filter for a needle after someone else had used it? 5. In the past month, how often did you use rinse water to clean needles after someone else had used it? The possible responses to the questions were coded as follows: 0=never, 1=sometimes, 2=about half the time, 3=often, 4=always. Before averaging the responses to the five questions, the responses to the second question were reversed coded to yield the same direction as the responses to the other four questions. IRI range: 0-20. Higher IRI--\>higher risk. |
Countries
Mexico
Participant flow
Recruitment details
Study recruitment took place between October 28, 2008 through May 31, 2010 in Tijuana and November 15, 2008 through July 30, 2010 in Ciudad Juarez. Data Collection for this study has been completed and the study is in the analysis phase.
Pre-assignment details
Targeted sampling techniques were used. Potential participants were approached at venues such as motels, hotels, brothels, shooting galleries, bars, alleys and street corners in both cities. Interested parties were referred to the project offices or a mobile unit for eligibility screening.
Participants by arm
| Arm | Count |
|---|---|
| A: Didactic Safer Injection & Sexual Activity Education In each city, 75 women will participate in a 60 minute lecture-format presentation and printed materials on safer sex and safer injection based on CDC guidelines for HIV counseling, testing, and referral and materials from Mexico's National Center for AIDS Studies (CENSIDA). In this component, there will be no theory-driven active skill building elements oriented towards safer sex or safer injection. | 144 |
| B: Interactive Injection Risk & Didactic Safer Sex Education In each city, 75 women will participate in the 60 minute Di No a las Jeringas Contaminadas \['Say No to Contaminated Syringes'\] counseling session. This one on one intervention incorporates elements of motivational interviewing (MI) and principles of SCT/TRA to address the context of unsafe injection sharing and the extent to which syringes and other injection paraphernalia is shared. In addition, participants will be provided a didactic presentation on safer sex. However, in this component, there will be no theory-driven active skill building elements oriented towards safer sex. | 146 |
| C:Interactive Sexual Risk & Didactic Safer Injection Education In each city, 75 women will participate in the 60 minute Di No Al Sexo Inseguro \[Say No to Unsafe Sex'\] counseling session. This one on one intervention incorporates elements of motivational interviewing (MI)and principles of social cognitive theory and theory of reasoned action (SCT/TRA) to address the context of unsafe sex and condom use with clients. In addition, participants will be provided a lecture-format presentation on safer injection sharing. However, in this component, there will be no theory-driven active skill building elements oriented towards safer injection behavior. | 148 |
| D: Interactive Injection & Sexual Risk Intervention In each city, 75 women will participate in the 60 minute Di No a las Jeringas Contaminadas \['Say No to Contaminated Syringes'\] and Di No Al Sexo Inseguro \[Say No to Unsafe Sex'\] counseling session. This one-on-one intervention incorporates elements of motivational interviewing (MI) and principles of Social Cognitive Theory and Theory of Reasoned Action (SCT/TRA) to address the context of both, a) unsafe injection sharing and the extent to which syringes and other injection paraphernalia is shared; and b) unsafe sex and condom use with clients, and associated risks (e.g., HIV, STIs, pregnancy). | 146 |
| Total | 584 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| Overall Study | Death | 2 | 2 | 3 | 3 |
| Overall Study | Lost to Follow-up | 3 | 1 | 2 | 1 |
Baseline characteristics
| Characteristic | A: Didactic Safer Injection & Sexual Activity Education | B: Interactive Injection Risk & Didactic Safer Sex Education | C:Interactive Sexual Risk & Didactic Safer Injection Education | D: Interactive Injection & Sexual Risk Intervention | Total |
|---|---|---|---|---|---|
| Age, Continuous | 33 years INTER_QUARTILE_RANGE 2742 | 32 years INTER_QUARTILE_RANGE 2740 | 34 years INTER_QUARTILE_RANGE 2740 | 34 years INTER_QUARTILE_RANGE 2940 | 33 years INTER_QUARTILE_RANGE 2740 |
| Region of Enrollment Mexico | 144 participants | 146 participants | 148 participants | 146 participants | 584 participants |
| Sex: Female, Male Female | 144 Participants | 146 Participants | 148 Participants | 146 Participants | 584 Participants |
| Sex: Female, Male Male | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | — / — | — / — | — / — | — / — |
| other Total, other adverse events | 0 / 144 | 0 / 146 | 0 / 148 | 0 / 146 |
| serious Total, serious adverse events | 5 / 144 | 3 / 146 | 8 / 148 | 4 / 146 |
Outcome results
Primary
Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis.
Combined incidence for HIV/STI was calculated over the 12-month study period and included only those who a) had at least one follow-up visit and b) at baseline tested negative for HIV and any of the aforementioned STIs. In the calculations we accounted for the time each participant spent at risk of HIV/any STI during the follow-up period, by using available information on each participant for each time point (i.e. baseline, 4-, 8-, and 12-months was used). The analytic method used for this outcome analysis was Poisson regression with robust variance estimation. The outcome variable was a binary variable indicating whether a participant has contracted HIV or a new STI during the 12-month follow-up period. The primary factor of interest was the intervention group. The log (time spent at risk of HIV/any STI) was used as an offset variable in order to account for the time spent at risk of HIV/any STI by each participant.
Time frame: 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| A: Didactic Safer Injection & Sexual Activity Education | Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis. | 65.02 incidence density per 100 person years |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis. | 67.66 incidence density per 100 person years |
| C:Interactive Sexual Risk & Didactic Safer Injection Eductatio | Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis. | 35.02 incidence density per 100 person years |
| D: Interactive Injection & Sexual Risk Intervention | Combined HIV/STI 12-month Incidence Rates of HIV, Syphilis, Chlamydia, Gonorrhea and Trichomonas Vaginalis. | 54.04 incidence density per 100 person years |
Secondary
Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients.
The analytic method used for a) was negative binomial regression with the number of unprotected sex acts with clients as the outcome variable and intervention group, time point (baseline, 4-, 8-, and 12-months), and the interaction between the two as the main effects of interest.
Time frame: 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline
Population: The data was analyzed by study location. In Tijuana, there were 284 participants (143 in the intervention and 141 in the control group) and in Ciudad Juarez there were 300 participants (151 in the intervention and 149 in the control group).
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (Baseline) | 37.91 Number of unprotected sex acts | Standard Deviation 46.79 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (Baseline) | 46.67 Number of unprotected sex acts | Standard Deviation 43.48 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (8-months) | 5.27 Number of unprotected sex acts | Standard Deviation 16.28 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (4-months) | 18.63 Number of unprotected sex acts | Standard Deviation 25.14 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (4-months) | 13.83 Number of unprotected sex acts | Standard Deviation 25.81 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (12-months) | 5.60 Number of unprotected sex acts | Standard Deviation 14.58 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (12-months) | 11.89 Number of unprotected sex acts | Standard Deviation 20.29 |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (8-months) | 15.98 Number of unprotected sex acts | Standard Deviation 21.92 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (12-months) | 18.76 Number of unprotected sex acts | Standard Deviation 26.53 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (Baseline) | 34.76 Number of unprotected sex acts | Standard Deviation 36.63 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (4-months) | 11.94 Number of unprotected sex acts | Standard Deviation 23.15 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (8-months) | 5.99 Number of unprotected sex acts | Standard Deviation 16.18 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Tijuana (12-months) | 5.38 Number of unprotected sex acts | Standard Deviation 16.35 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (Baseline) | 54.10 Number of unprotected sex acts | Standard Deviation 94.38 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (4-months) | 24.09 Number of unprotected sex acts | Standard Deviation 41.5 |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Number of Unprotected Sex Acts With Clients. | Ciudad Juarez (8-months) | 20.77 Number of unprotected sex acts | Standard Deviation 42.23 |
Secondary
Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI).
The injection risk index (IRI) was calculated by averaging the responses to the following five questions: 1. In the past month, how often have you used a needle or syringe that you knew or suspected had been used before by someone else? 2. In the past month, how often was a new syringe used to divide the drug? 3. In the past month, how often did you use a bottle-cap/spoon/cooker after someone else had used it? 4. In the past month, how often did you use a cotton filter for a needle after someone else had used it? 5. In the past month, how often did you use rinse water to clean needles after someone else had used it? The possible responses to the questions were coded as follows: 0=never, 1=sometimes, 2=about half the time, 3=often, 4=always. Before averaging the responses to the five questions, the responses to the second question were reversed coded to yield the same direction as the responses to the other four questions. IRI range: 0-20. Higher IRI--\>higher risk.
Time frame: 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline
Population: Analyses for the secondary outcomes were stratified by site. Of the total 292 participants in the Intervention Group, 142 were in Tijuana and 150 in Cd. Juarez. Similarly, of the 292 participants in the Control Group, 142 were in Tijuana and 150 in Cd Juarez.
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (Baseline) | 3.393 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (4 Months) | 1.916 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (8 months) | 1.697 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (12 months) | 1.551 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (baseline) | 3.236 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (4 months) | 2.418 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (8 months) | 2.146 IRI Score |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (12 months) | 1.827 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (12 months) | 2.070 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (Baseline) | 3.358 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (baseline) | 3.07 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (4 Months) | 1.855 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (8 months) | 2.311 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (8 months) | 1.648 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Ciudad Juarez (4 months) | 2.362 IRI Score |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Mean Score of the Injection Risk Index (IRI). | Tijuana (12 months) | 1.542 IRI Score |
Comparison: Alternative hypothesis: There is a difference between the intervention and the control group with respect to the change in the mean score IRI (i.e., The interaction between study visit (baseline, 4-, 8-, and 12-months) and intervention group will be significant at 0.05 significance level. Over time, the intervention group will experience a significant decline in the IRI but the control group will not.)p-value: 0.013Mixed Models Analysis
Secondary
Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing
For a) we asked: In the past month, how often have you used a needle or syringe that you knew or suspected had been used before by someone else? (possible responses: 1=never, 2=sometimes, 3=about half the time, 4=often, 5=always), with a higher response indicating a higher risk. The intervention effect was evaluated by conducting ordinal logistic regression, with the frequency of receptive needle sharing as the outcome variable and Group (Intervention vs. Control), Visit (Baseline, 4-months, 8-months, and 12-months) and the interaction term between the two (Visit\*Group) as the main effects. Our primary interest was the Visit\*Group interaction, with a significant corresponding p-value being indicative of an intervention effect.
Time frame: 12 months, with measuring points at baseline and at 4, 8, and 12 months past baseline
Population: Analyses for the secondary outcomes were stratified by site. Of the total 292 participants in the Intervention Group, 142 were in Tijuana and 150 in Cd. Juarez. Similarly, of the 292 participants in the Control Group, 142 were in Tijuana and 150 in Cd Juarez.
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (Baseline) | 3.01 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (4 Months) | 0.32 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (8 Months) | 0.18 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (12 months) | 0.15 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (baseline) | 2.45 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (4 months) | 0.85 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (8 months) | 0.53 Odds Receptive Needle Sharing |
| A: Didactic Safer Injection & Sexual Activity Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (12 months) | 0.38 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (12 months) | 0.56 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (Baseline) | 2.83 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (baseline) | 1.911 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (4 Months) | 0.26 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (8 months) | 0.71 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (8 Months) | 0.16 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Ciudad Juarez (4 months) | 0.69 Odds Receptive Needle Sharing |
| B: Interactive Injection Risk & Didactic Safer Sex Education | Change (Baseline to 4-, 8-, and 12-months) in the Proportional Odds of Higher Receptive Needle Sharing | Tijuana (12 months) | 0.13 Odds Receptive Needle Sharing |
Comparison: Alternative hypothesis: There is a difference between the intervention and the control group with respect to the change in the odds of higher receptive needle sharing. (i.e., The interaction between study visit (baseline, 4-, 8-, and 12-months) and intervention group will be significant at 0.05 significance level. Over time, the intervention group will experience a significant decline in receptive needle sharing but the control group will not.)p-value: 0.036Mixed Models Analysis