Table 1.
Network variablesa associated with individual HIV seroprevalence among people who inject drugs in Athens, Greece 2012.
| Univariate | Multivariableb | Clustered Bootstrapb, c | |||||||
|---|---|---|---|---|---|---|---|---|---|
| NETWORK LEVEL VARIABLESd | N | % HIV+ | Odds Ratio | 95% CI | P value | Adjusted Odds Ratio | 95% CI | P value | P value |
| Network HIV Seroprevalence | |||||||||
| HIV infected | |||||||||
| Low (0) | 671 | 13.0 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 109 | 33.0 | 3.31 | (2.09,5.24) | <0.001 | 2.98 | (1.76,5.05) | <0.001 | <0.001 |
| High (≥50) | 249 | 36.9 | 3.93 | (2.79,5.54) | <0.001 | 3.11 | (2.10,4.62) | <0.001 | <0.001 |
| Network Characteristics | |||||||||
| Homelesse | |||||||||
| Low (0) | 470 | 16.8 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 137 | 27 | 1.83 | (1.17,2.87) | 0.008 | 1.55 | (0.93,2.60) | 0.09 | 0.09 |
| High (≥50) | 422 | 23.5 | 1.52 | (1.09,2.11) | 0.01 | 1.13 | (0.77,1.66) | 0.52 | 0.43 |
| Primary school only | |||||||||
| Low (0) | 583 | 18.5 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 138 | 26.8 | 1.61 | (1.05,2.48) | 0.03 | 1.49 | (0.91,2.45) | 0.11 | 0.16 |
| High (≥50) | 308 | 22.7 | 1.29 | (0.92,1.81) | 0.14 | 1.02 | (0.69,1.51) | 0.92 | 0.93 |
| Ever in prison | |||||||||
| 0 | 308 | 15.6 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 87 | 29.9 | 2.31 | (1.33,4.01) | 0.003 | 2.82 | (1.48,5.37) | 0.002 | 0.004 |
| High (≥50) | 633 | 22.3 | 1.55 | (1.08,2.23) | 0.02 | 1.41 | (0.94,2.12) | 0.10 | 0.09 |
| Network Prevention Activities | |||||||||
| Receives condoms | |||||||||
| Low (0) | 263 | 16.7 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 61 | 9.8 | 0.54 | (0.22,1.34) | 0.18 | 0.41 | (0.13,1.26) | 0.12 | 0.16 |
| High (≥50) | 704 | 23.4 | 1.52 | (1.05,2.20) | 0.02 | 1.13 | (0.75,1.72) | 0.55 | 0.48 |
| Receives syringes | |||||||||
| Low (0) | 247 | 13.8 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 62 | 17.7 | 1.35 | (0.64,2.85) | 0.43 | 1.57 | (0.68,3.62) | 0.29 | 0.35 |
| High (≥50) | 720 | 23.6 | 1.94 | (1.30,2.89) | 0.001 | 1.46 | (0.93,2.28) | 0.10 | 0.14 |
| Network Risk Behaviorse | |||||||||
| Main drug non-heroin | |||||||||
| Low (0) | 717 | 18.7 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 115 | 24.3 | 1.40 | (0.88,2.23) | 0.16 | 1.40 | (0.82,2.39) | 0.21 | 0.33 |
| High (≥50) | 197 | 26.9 | 1.60 | (1.11,2.31) | 0.01 | 1.43 | (0.93,2.21) | 0.10 | 0.10 |
| Divides drugs | |||||||||
| Low (0) | 446 | 15.2 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 113 | 24.8 | 1.83 | (1.11,3.02) | 0.02 | 1.85 | (1.05,3.27) | 0.03 | 0.08 |
| High (≥50) | 465 | 25.2 | 1.87 | (1.34,2.61) | 0.0002 | 1.60 | (1.10,2.35) | 0.02 | 0.01 |
| High frequency injecting | |||||||||
| Low (0) | 405 | 14.6 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 97 | 17.5 | 1.25 | (0.69,2.25) | 0.46 | 1.11 | (0.58,2.12) | 0.75 | 0.80 |
| High (≥50) | 527 | 26.4 | 2.10 | (1.50,2.94) | <0.0001 | 1.50 | (1.02,2.21) | 0.04 | 0.11 |
| Shares cookers, filters or water | |||||||||
| Low (0) | 177 | 13.6 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 59 | 30.5 | 2.80 | (1.39,5.65) | 0.004 | 2.44 | (1.10,5.38) | 0.03 | 0.44 |
| High (≥50) | 793 | 21.8 | 1.78 | (1.12,2.82) | 0.01 | 1.54 | (0.92,2.57) | 0.10 | 0.29 |
| Shares syringes | |||||||||
| Low (0) | 406 | 18 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 129 | 22.5 | 1.32 | (0.81,2.15) | 0.07 | 1.30 | (0.75,2.27) | 0.35 | 0.44 |
| High (≥50) | 493 | 22.9 | 1.36 | (0.98,1.89) | 0.004 | 1.25 | (0.86,1.82) | 0.25 | 0.29 |
| Other Network Characteristics | |||||||||
| Acquaintance | |||||||||
| Low (0) | 488 | 19.1 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 172 | 18.6 | 0.97 | (0.62,1.52) | 0.90 | 0.91 | (0.54,1.52) | 0.71 | |
| High (≥50) | 370 | 24.6 | 1.39 | (1.00,1.92) | 0.05 | 1.28 | (0.87,1.86) | 0.21 | |
| Friend | |||||||||
| Low (0) | 434 | 17.7 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 194 | 23.7 | 1.44 | (0.95,2.18) | 0.08 | 1.26 | (0.78,2.03) | 0.34 | 0.35 |
| High (≥50) | 402 | 23.1 | 1.40 | (0.99,1.96) | 0.05 | 1.37 | (0.93,2.02) | 0.11 | 0.14 |
| Stranger | |||||||||
| Low (0) | 678 | 23.5 | 1.00 | 1.00 | |||||
| Moderate (1 – 49) | 158 | 16.5 | 0.64 | (0.41,1.01) | 0.06 | 0.63 | (0.38,1.04) | 0.07 | 0.14 |
| High (≥50) | 194 | 16 | 0.62 | (0.41,0.95) | 0.03 | 0.66 | (0.40,1.07) | 0.09 | 0.13 |
Each network variable represents a separate model. Multivariable models include the network variable indicated and individual-level covariates.
Individual-level covariates that had significant associations with HIV seroprevalence at the p<0.1 level in the univariable analyses were included for all multivariate models: age, sex, homelessness, highest level of education, history of incarceration, getting condoms from an HIV prevention activity, getting syringes from an HIV prevention activity, getting condoms from an HIV prevention activity, ever being in drug treatment, using divided drugs with a syringe that has already been used, frequency of injection, drug injected most often, sharing cookers/water or filters, sharing syringes, using alcohol or drugs with last sex partner and having unprotected sex.
Clustered Bootstrap model consisted of 48 roughly equal sized clusters sampled over approximately 1000 repetitions.
Network-level variables were measured as network proportions. For example, if an individual has 4 network members and 3 are HIV infected, that individual’s HIV infected network proportion is 0.75
Results reflect behavior in past 12 months