Associations of baseline characteristics with pharyngeal chlamydia in 13 111 men who have sex with men (MSM), STI clinic, Public Health Service of Amsterdam, 2011–2012
| Pharyngeal chlamydia | Univariate analysis | Multivariable analysis | ||||
|---|---|---|---|---|---|---|
| Negative | Positive | |||||
| N=12 963 | N=148 | |||||
| Variable | n (%) | n (%) | OR (95% CI) | p Value | aOR (95% CI) | p Value |
| Demographics | ||||||
| Median age (IQR) in years* | 39 (31–47) | 36 (29–46) | 0.028 | |||
| Age in years | ||||||
| <30 | 2713 (20.9%) | 37 (25.0%) | 1 | 0.12 | 1 | 0.37 |
| 30–39 | 3908 (30.1%) | 51 (34.5%) | 0.96 (0.63 to 1.47) | 0.95 (0.61 to 1.49) | ||
| 40–49 | 3964 (30.6%) | 43 (29.1%) | 0.80 (0.51 to 1.24) | 0.81 (0.51 to 1.30) | ||
| ≥50 | 2378 (18.3%) | 17 (11.5%) | 0.52 (0.29 to 0.93) | 0.61 (0.33 to 1.11) | ||
| Ethnicity | ||||||
| Dutch | 8069 (62.2%) | 81 (54.7%) | 1 | 0.062 | ||
| Non-Dutch | 4894 (37.8%) | 67 (45.3%) | 1.36 (0.99 to 1.89) | |||
| Sexual behaviour | ||||||
| Getting paid for sex in previous 6 months | 259 (2.0%) | 4 (2.7%) | 1.36 (0.50 to 3.71) | 0.55 | ||
| Paying for sex in previous 6 months | 106 (0.8%) | 1 (0.7%) | 0.83 (0.11 to 5.95) | 0.85 | ||
| Median number of sexual partners in previous 6 months (IQR)* | 5 (3–12) | 8 (4–20) | 0.003 | |||
| Number of sexual partners in previous 6 months | ||||||
| 0–4 | 5413 (41.8%) | 47 (31.8%) | 1 | 0.008 | 1 | 0.023 |
| 5–10 | 4200 (32.4%) | 47 (31.8%) | 1.29 (0.86 to 1.94) | 1.19 (0.78 to 1.80) | ||
| >10 | 3350 (25.8%) | 54 (36.5%) | 1.86 (1.25 to 2.75) | 1.74 (1.16 to 2.63) | ||
| Active oral sex in previous 6 months | 0.29 | |||||
| Unknown | 423 (3.3%) | 1 (0.7%) | ||||
| No | 247 (1.9%) | 2 (1.4%) | ||||
| Yes, with condom | 184 (1.4%) | 1 (0.7%) | ||||
| Yes, without condom | 12 109 (93.4%) | 144 (97.3%) | ||||
| Reason for visit | ||||||
| Was notified by sexual partner | 1967 (15.2%) | 43 (29.1%) | 2.29 (1.60 to 3.28) | <0.001 | 1.56 (1.07 to 2.27) | 0.020 |
| Had STI-related complaints | 3602 (27.8%) | 45 (30.4%) | 1.14 (0.80 to 1.62) | 0.48 | ||
| Had pharyngeal complaints | 285 (2.2%) | 2 (1.4%) | 0.61 (0.15 to 2.47) | 0.49 | ||
| New STI diagnosis at current visit | ||||||
| STI diagnosis† | 2667 (20.6%) | 84 (56.8%) | 5.07 (3.65 to 7.03) | <0.001 | ||
| Chlamydia (excl. pharyngeal CT)ठ| 1280/12 955 (9.9%) | 70/148 (47.3%) | 8.19 (5.90 to 11.36) | <0.001 | ||
| Anorectal chlamydia‡ | ||||||
| Not tested | 2945 (22.7%) | 26 (17.6%) | 1.29 (0.81 to 2.03) | 1.22 (0.76 to 1.95) | ||
| Negative | 9168 (70.7%) | 63 (42.6%) | 1 | <0.001 | 1 | <0.001 |
| Positive | 850 (6.6%) | 59 (39.9%) | 10.10 (7.03 to 14.51) | 8.14 (5.54 to 11.97) | ||
| Urogenital chlamydia§ | 550/12 918 (4.3%) | 20/147 (13.6%) | 3.54 (2.19 to 5.72) | <0.001 | 1.98 (1.19 to 3.29) | 0.008 |
| Anorectal gonorrhoea§ | 569/12 891 (4.4%) | 18/148 (12.2%) | 3.00 (1.82 to 4.94) | <0.001 | ||
| Urogenital gonorrhoea§ | 357/12 926 (2.8%) | 5/148 (3.4%) | 1.23 (0.50 to 3.02) | 0.65 | ||
| Pharyngeal gonorrhoea | 709 (5.5%) | 15 (10.1%) | 1.95 (1.14 to 3.34) | 0.015 | ||
| HIV status¶ | ||||||
| Unknown | 212 (1.6%) | 8 (5.4%) | 3.43 (1.64 to 7.14) | 3.09 (1.44 to 6.61) | ||
| Negative | 8533 (65.8%) | 94 (63.5%) | 1 | 0.001 | 1 | 0.002 |
| Positive | 4218 (32.5%) | 46 (31.1%) | 0.99 (0.69 to 1.41) | 0.76 (0.52 to 1.12) | ||
| Early syphilis§ | 321/12 956 (2.5%) | 7/148 (4.7%) | 1.95 (0.91 to 4.21) | 0.087 | ||
All variables with p<0.10 in univariate analysis were included in the multivariable model, except the two summarising variables STI diagnosis and chlamydia (excl. pharyngeal CT). Patients who had missing values in STI testing were excluded from the multivariable model. The total number of records included in the multivariable model was 12 986.
*Mann-Whitney U Test for comparing not normally distributed continuous variables.
†STI diagnosis is defined as being diagnosed with Chlamydia trachomatis (excluding pharyngeal CT), gonorrhoea (any location), infectious hepatitis B, HIV, and/or early syphilis at time of current visit. This combined variable was not included in the multivariable analyses.
‡Only MSM reporting passive anal sex were tested for anorectal chlamydia.
§In some cases no material was available or the laboratory test failed.
¶Only MSM who were not already known to be HIV-positive were offered an HIV-test. HIV status was considered unknown when no history of HIV was reported and no HIV test was performed at current visit; negative when the HIV serology test was negative at current visit; and positive when reporting a history of HIV or when the HIV serology test was positive at current visit.
aOR, adjusted OR; excl., excluding; incl., including; STI, sexually transmitted infection.