TABLE 2—
Bivariate, Blocked, and Multivariable Model Results for Polydrug Use and Marijuana Use in the Past 3 Months: Centers for AIDS Research Network of Integrated Clinical Systems Cohort: United States, 2005–2010
| Characteristic | Bivariate Models,a Crude OR (95% CI) | Blocked Models,b Adjusted OR (95% CI) | Model 1c (n = 3413), Adjusted OR (95% CI) | Model 2d (n = 2618), Adjusted OR (95% CI) | Model 3e (n = 1292), Adjusted OR (95% CI) | Model 4f (n = 656), Adjusted OR (95% CI) | |
| Polydrug use | |||||||
| Demographic characteristics | |||||||
| Age, y | 0.97** (0.96, 0.98) | 0.97** (0.96, 0.98) | 0.98** (0.97, 0.99) | 0.98** (0.97, 0.99) | 0.99** (0.98, 0.99) | 0.99 (0.98, 1.01) | |
| Gender | 1.71** (1.26, 2.31) | 1.73** (1.20, 2.51) | 2.01** (1.55, 2.61) | 2.06** (1.52, 2.79) | 0.98 (0.38, 2.52) | 1.87** (1.5, 2.12) | |
| Latino/Hispanic (vs White) | 1.03 (0.93, 1.13) | 0.94 (0.84, 1.05) | 1.10 (0.98, 1.23) | 0.92 (0.66, 1.27) | 1.27* (1.01, 1.60) | 0.80 (0.48, 1.36) | |
| Black (vs White) | 1.18 (0.95, 1.46) | 1.20 (0.89, 1.61) | 1.21 (0.94, 1.56) | 1.05 (0.76, 1.44) | 1.17 (0.88, 1.56) | 1.31* (1.04, 1.66) | |
| Other (vs White) | 0.93 (0.59, 1.48) | 0.90 (0.55, 1.49) | 1.00 (0.61, 1.61) | 1.25 (0.80, 1.94) | 1.24 (0.50, 3.04) | 1.40 (0.87, 2.28) | |
| HIV disease characteristics and medication adherence | |||||||
| Currently taking HIV medications | 0.57** (0.45, 0.73) | … | 0.82 (0.58, 1.15) | … | 0.99 (0.56, 1.74) | 0.89 (0.50, 1.59) | |
| Detectable viral load | 1.89** (1.61, 2.21) | 1.34* (1.06, 1.68) | 1.45** (1.22, 1.72) | 1.21* (1.01, 1.46) | 1.33 (0.92, 1.92) | 1.55** (1.31, 1.82) | |
| Nonadherence score | 1.52** (1.26, 1.83) | 1.48** (1.23, 1.79) | … | 1.39** (1.16, 1.66) | … | … | |
| Psychosocial factors | |||||||
| Major depression | 2.23** (2.01, 2.47) | 1.73** (1.58, 1.88) | 1.79** (1.64, 1.96) | 1.48** (1.29, 1.71) | 1.93** (1.77, 2.09) | 1.39** (1.24, 1.57) | |
| Anxiety disorder | 2.02** (1.42, 2.88) | 1.40 (0.90, 2.18) | 1.38 (0.92, 2.07) | 1.21 (0.84, 1.74) | 1.76** (1.30, 2.39) | 1.35 (0.90, 2.02) | |
| Drug treatment | 4.06** (3.81, 4.33) | 3.39** (3.09, 3.72) | 3.33** (3.08, 3.61) | 3.40** (3.14, 3.69) | 2.40** (1.87, 3.0) | 2.94** (2.19, 3.95) | |
| HIV sexual risk behavior | |||||||
| Unprotected anal sex | 2.27** (1.92, 2.67) | 1.83** (1.49, 2.24) | … | … | 1.54** (1.28, 1.86) | … | |
| No. of anal sex partners | 1.32** (1.22, 1.42) | 1.27** (1.19, 1.35) | … | … | 1.23** (1.15, 1.31) | … | |
| Unprotected vaginal sex | 1.21 (0.79, 1.87) | 1.20 (0.78, 1.83) | … | … | … | 1.05 (0.76, 1.45) | |
| No. of vaginal sex partners | 0.93** (0.90, 0.97) | 1.18** (1.13, 1.23) | … | … | … | 1.07** (1.04, 1.09) | |
| Marijuana use | |||||||
| Demographic characteristics | |||||||
| Age, y | 0.98** (0.97, 0.99) | 0.98** (0.96, 0.99) | 0.98** (0.87, 0.99) | 0.98* (0.97, 0.99) | 0.99 (0.97, 1.01) | 0.96** (0.95, 0.97) | |
| Gender | 1.97** (1.41, 2.75) | 1.86** (1.40, 2.46) | 1.97** (1.41, 2.74) | 2.31** (1.38, 3.86) | 1.55 (0.82, 2.93) | 1.94** (1.47, 2.56) | |
| Latino/Hispanic (vs White) | 0.84* (0.70, 0.99) | 0.77** (0.63, 0.93) | 0.81** (0.69, 0.95) | 0.73** (0.56, 0.96) | 0.90 (0.62, 1.30) | 0.90 (0.45, 1.81) | |
| Black (vs White) | 0.77** (0.69, 0.86) | 0.81** (0.70, 0.93) | 0.83* (0.73, 0.95) | 0.75** (0.61, 0.92) | 0.97 (0.74, 1.27) | 1.24 (0.86, 1.79) | |
| Other (vs White) | 0.95 (0.74, 1.20) | 0.92 (0.71, 1.19) | 0.96 (0.77, 1.21) | 1.17 (0.85, 1.61) | 0.88 (0.53, 1.46) | 1.77 (0.90, 3.49) | |
| HIV disease characteristics and medication adherence | |||||||
| Currently taking HIV medications | 0.85* (0.75, 0.97) | … | 0.95 (0.84, 1.09) | … | 1.01 (0.92, 1.12) | 0.83 (0.49, 1.40) | |
| Detectable viral load | 1.21** (1.15, 1.28) | 1.04 (0.94, 1.15) | 1.08 (0.98, 1.20) | 0.99 (0.89, 1.10) | 1.02 (0.83, 1.26) | 1.38* (1.06, 1.78) | |
| Nonadherence score | 1.13 (0.99, 1.29) | 1.13 (0.99, 1.28) | … | 1.10 (0.98, 1.24) | … | … | |
| Psychosocial factors | |||||||
| Major depression | 1.62** (1.21, 2.18) | 1.49** (1.31, 1.70) | 1.51** (1.30, 1.75) | 1.41** (1.33, 1.50) | 1.56** (1.25, 1.94) | 1.31 (0.86, 2.00) | |
| Anxiety disorder | 1.46 (0.86, 2.38) | 1.22 (0.75, 1.99) | 1.19 (0.73, 1.93) | 1.17 (0.70, 1.96) | 1.65** (1.30, 2.10) | 1.90* (1.02, 3.55) | |
| Drug treatment | 1.32** (1.16, 1.50) | 1.19* (1.04, 1.36) | 1.15* (1.01, 1.32) | 1.05 (0.91, 1.23) | 0.74** (0.64, 0.85) | 1.36 (0.87, 2.13) | |
| HIV sexual risk behavior | |||||||
| Unprotected anal sex | 1.26** (1.10, 1.45) | 1.20** (1.07, 1.34) | … | … | 1.13* (1.00, 1.28) | … | |
| No. of anal sex partners | 1.12** (1.08, 1.17) | 1.08** (1.04, 1.12) | … | … | 1.06** (1.02, 1.11) | … | |
| Unprotected vaginal sex | 1.03 (0.76, 1.40) | 1.02 (0.72, 1.44) | … | … | … | 0.93 (0.71, 1.21) | |
| No. of vaginal sex partners | 0.78** (0.69, 0.89) | 1.21 (0.97, 1.51) | … | … | … | 1.12 (0.92, 1.35) | |
Note. CI = confidence interval; OR = odds ratio. Generalized estimating equations were used to fit logit models to adjust for geographic location (the design covariate in all models was study site).
Results from fitted bivariate logistic regression models.
Results from multivariable logistic regression models examining block group baseline factors (e.g., domain-specific variables) associated with substance use.
Includes all participants. Statistical predictors were age, gender, race/ethnicity, currently taking HIV medication, detectable viral load, depression, anxiety, and substance use treatment in the preceding year.
Restricted to participants who reported currently taking HIV medications. This model included the same variables as model 1 with the addition of medication nonadherence.
Restricted to participants who reported anal sex in the preceding 6 months. This model included the same variables as model 1 with the addition of unprotected anal sex and number of anal sex partners.
Restricted to participants who reported vaginal sex in the preceding 6 months. This model included the same variables as model 1 with the addition of unprotected vaginal sex and number of vaginal sex partners. The model was not fit for the injection drug use outcome owing to an insufficient sample size.
*P < .05; **P < .001.