Table 2.
Full and reduced-form prediction rule models and penalized odds ratios for the associations of potential predictors with HIV risk
| Potential items for sexual risk score | Type | df | PMLE model |
|
|---|---|---|---|---|
| Full model | Reduced-form model | |||
| Age at recruitment (change from 24 to 33 years) | Continuous | 3 | 1.16 (0.79, 1.77) | n/a |
| Currently married with a woman | Dichotomous | 1 | 0.80 (0.53, 1.21) | n/a |
| Beijing Hukou | Dichotomous | 1 | 0.55 (0.38, 0.82) | 0.55 (0.38, 0.81) |
| Years of living in Beijing (change from 2 to 10 years) | Continuous | 2 | 0.66 (0.51, 0.86) | 0.67 (0.52, 0.86) |
| Nitrite inhalants use in the past 3 months | Dichotomous | 1 | 1.04 (0.82, 1.32) | n/a |
| Illegal drug use in the past 3 months | Dichotomous | 1 | 4.34 (2.40, 7.87) | 4.35 (2.43, 7.76) |
| Alcohol use in the past 3 months | Ordinal | 3 | ||
| (≤1 time/month vs. never) | 1.36 (1.04, 1.77) | n/a | ||
| (2–4 times/month vs. never) | 1.33 (0.96, 1.84) | n/a | ||
| (≥5 times/month vs. never) | 1.06 (0.68, 1.66) | n/a | ||
| Alcohol consumption before sex in the past 3 months | Ordinal | 3 | ||
| (occasionally vs. never) | 1.17 (0.85, 1.62) | 1.13 (0.85, 1.50) | ||
| (sometimes vs. never) | 1.29 (0.76, 2.19) | 1.27 (0.78, 2.06) | ||
| (often vs. never) | 2.98 (1.45, 6.10) | 2.83 (1.48, 5.39) | ||
| Time since the first sex (change from 4 to 12 years) | Continuous | 3 | 1.67 (0.95, 2.91) | 1.35 (1.02, 1.78) |
| Time since the first anal sex (change from 3 to 10 years) | Continuous | 3 | 0.75 (0.48, 1.18) | n/a |
| Number of lifetime male sexual partners (from 4 to 20) | Continuous | 3 | 1.45 (1.15, 1.83) | 1.41 (1.13, 1.75) |
| Number of male sexual partners in the past 3 months (from 1 to 2) | Continuous | 3 | 0.84 (0.72, 0.98) | 0.85 (0.73, 0.99) |
| Frequency of receptive anal sex in the past 3 months (from 0 to 3) | Continuous | 2 | 1.75 (1.30, 2.35) | 1.67 (1.25, 2.24) |
| Proportion of condom use during receptive anal sex with male partners in the past 3 months (from 0% to 100%) | Continuous | 3 | 0.53 (0.37, 0.77) | 0.49 (0.34, 0.69) |
| Frequency of insertive anal sex in the past 3 months (from 0 to 4) | Continuous | 2 | 0.70 (0.52, 0.93) | 0.78 (0.60, 1.01) |
| Proportion of condom use during insertive anal sex with male partners in the past 3 months (from 0% to 100%) | Continuous | 3 | 0.70 (0.48, 1.02) | n/a |
| Sex with female partners in the past 3 months | Dichotomous | 1 | 0.56 (0.27, 1.14) | 0.53 (0.34, 0.81) |
| Condom use during sex with female partners in the past 3 months | Ordinal | 2 | ||
| (sometimes vs. consistent) | 0.77 (0.22, 2.67) | n/a | ||
| (never vs. consistent) | 0.69 (0.21, 2.30) | n/a | ||
| Syphilis infection | Dichotomous | 1 | 2.87 (2.11, 3.91) | 2.89 (2.13, 3.93) |
| Original c-index | Total df | 40 | 0.73 | 0.72 |
| Bias-corrected c-index | 0.70 | 0.71 | ||
Note: df, degree of freedom; PMLE, penalized maximum likelihood estimation; UOR, unadjusted odds ratio; AOR, adjusted odds ratio; CI, confidence interval; n/a, not available.