Table 1.
The impact of serosorting and strategic positioning on sexually transmissible infections in the Health in Men study
| n | Incidence Per 100 PY | Univariate analysis | Multivariate analysis1 | |||||
|---|---|---|---|---|---|---|---|---|
| HR | 95% CI | P value | Adjusted HR | 95% CI | P value | |||
| Serosorting | ||||||||
| vs. No UAI | ||||||||
| Bacterial STIs | ||||||||
| Urethral chlamydia | 0.001 | <0.001 | ||||||
| Serosorting | 99 | 6.06 | 1.75 | 1.27–2.41 | 1.97 | 1.43–2.72 | ||
| No UAI | 61 | 3.56 | 1 | --- | 1 | --- | ||
| Anal chlamydia | 0.072 | 0.013 | ||||||
| Serosorting | 64 | 3.95 | 1.41 | 0.97–2.05 | 1.62 | 1.11–2.36 | ||
| No UAI | 48 | 2.80 | 1 | --- | 1 | --- | ||
| Viral STIs | ||||||||
| HSV-1 | 0.057 | 0.059 | ||||||
| Serosorting | 31 | 9.09 | 1.68 | 0.99–2.86 | 1.68 | 0.98–2.87 | ||
| No UAI | 24 | 5.51 | 1 | --- | 1 | --- | ||
| vs. Non-concordant UAI (Non SS) | ||||||||
| Bacterial STIs | ||||||||
| Syphilis | 0.011 | 0.023 | ||||||
| Serosorting | 3 | 0.18 | 0.19 | 0.05–0.68 | 0.21 | 0.05–0.81 | ||
| Non SS | 10 | 1.00 | 1 | --- | 1 | --- | ||
| Urethral gonorrhoea | <0.001 | 0.033 | ||||||
| Serosorting | 35 | 2.15 | 0.41 | 0.27–0.63 | 0.61 | 0.39–0.96 | ||
| Non SS | 56 | 5.52 | 1 | --- | 1 | --- | ||
| Anal gonorrhoea | 0.004 | 0.090 | ||||||
| Serosorting | 39 | 2.40 | 0.54 | 0.35–0.82 | 0.67 | 0.43–1.06 | ||
| Non SS | 46 | 4.55 | 1 | --- | 1 | --- | ||
| Urethral chlamydia | <0.001 | 0.136 | ||||||
| Serosorting | 99 | 6.06 | 0.55 | 0.42–0.72 | 0.80 | 0.60–1.07 | ||
| Non SS | 114 | 11.34 | 1 | --- | 1 | --- | ||
| Anal chlamydia | <0.001 | 0.109 | ||||||
| Serosorting | 64 | 3.95 | 0.51 | 0.37–0.71 | 0.75 | 0.53–1.07 | ||
| Non SS | 80 | 7.93 | 1 | --- | 1 | --- | ||
| Strategic positioning | ||||||||
| vs. No UAI | ||||||||
| Bacterial STIs | ||||||||
| Urethral gonorrhoea | 0.008 | 0.032 | ||||||
| Strategic positioning | 28 | 4.11 | 1.95 | 1.19–3.20 | 1.72 | 1.05–2.83 | ||
| No UAI | 36 | 2.10 | 1 | --- | 1 | --- | ||
| Urethral chlamydia | <0.001 | <0.001 | ||||||
| Strategic positioning | 59 | 8.71 | 2.46 | 1.72–3.53 | 2.22 | 1.55–3.18 | ||
| No UAI | 61 | 3.56 | 1 | --- | 1 | --- | ||
| vs. Receptive UAI | ||||||||
| Bacterial STIs | ||||||||
| Anal gonorrhoea | 0.005 | 0.004 | ||||||
| Strategic positioning | 10 | 1.48 | 0.39 | 0.20–0.75 | 0.38 | 0.20–0.74 | ||
| Receptive UAI | 75 | 3.83 | 1 | --- | 1 | --- | ||
| Anal chlamydia | 0.003 | <0.001 | ||||||
| Strategic positioning | 21 | 3.10 | 0.49 | 0.31–0.78 | 0.44 | 0.27–0.69 | ||
| Receptive UAI | 123 | 6.30 | 1 | --- | 1 | --- | ||
UAI: unprotected anal intercourse; STI: sexually transmissible infection;
Bacterial STIs examined included syphilis, gonorrhoea (urethral and anal) and chlamydia (urethral and anal); Viral STIs examined included herpes simplex virus types 1 and 2, genital and anal warts.
1
adjusted for age and number of sexual partners reported in the last 6 months.