Demographic characteristics and sexual behaviour of the study population
Between 20/2/2018 and 2/7/2018, 2321 MSM participated in the study, between 32 and 312 MSM by each site. Complete test results for all four pathogens and information on HIV-status were available for 2303 of them, constituting the final study population. 50.5% (1164/2303) of all participants were HIV+. 91.4% of them were diagnosed with HIV longer than 12 months before study entry, 98.4% were on antiviral treatment and 84.2% reported a viral load below the detection limit. Of the HIV- participants, 27.6% (283/1024) reported current PrEP use (HIV−/PrEP+), 72.4% (741/1024) did currently not taking PrEP (HIV−/PrEP-).
34.2% of all participating MSM were between 30 and 40 years old (Table
1), HIV+ MSM were older than HIV−/PrEP- and HIV−/PrEP+ (median 44 [20–79] vs. 34 [18–73] and 35 [20–66]). Participants not being born in Germany (25.9%) came from various countries all over the world, mostly from Brazil (7.4% of foreign born MSM), United States of America (6.4%), Italy (6.0%), and Poland (5.5%). HIV−/PrEP+ were more often born abroad (37.2%) than HIV−/PrEP- (30.9%) and HIV+ (19.2%). HIV−/PrEP+ and HIV−/PrEP- had more often a university-entrance diploma (80.2 and 79.5%) than HIV+ (54.4%).
Table 1
Sociodemographic, behavioral and clinical characteristics of the study population, by HIV/PrEP-status
Demographicsc |
Age (median [range]; n = 2287) | 39 [18–79] | 44 [20–79] | 34 [18–73] | 35 [20–66] |
Born in Germany (%; n = 2168) | 74.5 | 80.8 | 69.1 | 62.8 |
University-entrance diploma (%; n = 2157) | 66.2 | 54.4 | 79.5 | 80.2 |
Sexual behavior in the last 6 months |
Number of sex partners (median [range]; n = 1935) | 5 [0–820] | 4 [0–820] | 5 [0–120] | 11 [1–240] |
Sex without condom (%, n = 2148) | 73.6 | 73.1 | 67.3 | 91.8 |
Condomless anal intercourse (insertive; %; n = 2076) | 55.7 | 56.8 | 51.5 | 78.4 |
Condomless anal intercourse (receptive; %; n = 2077) | 59.2 | 63.7 | 46.6 | 73.8 |
Condomless oral intercourse (insertive; %; n = 2077) | 87.2 | 83.9 | 89.6 | 94.0 |
Condomless oral intercourse (receptive; %; n = 2078) | 81.2 | 76.1 | 85.9 | 88.7 |
Rimming (active; %; n = 2075) | 54.9 | 49.3 | 56.0 | 73.1 |
Rimming (passive; %; n = 2076) | 58.1 | 52.4 | 62.1 | 77.0 |
Fisting (active; %; n = 2072) | 15.5 | 16.0 | 11.8 | 23.0 |
Fisting (passive; %; n = 2072) | 9.6 | 11.7 | 5.9 | 11.7 |
Use of drugs (%; n = 2123) | 67.7 | 64.3 | 66.6 | 84.2 |
Use of party drugs (%; n = 2123) | 44.6 | 42.9 | 39.6 | 64.4 |
Paid for sex (%; n = 1814) | 3.5 | 3.7 | 3.4 | 2.7 |
Being paid for sex (%; n = 1791) | 2.8 | 2.9 | 2.9 | 2.6 |
STI history |
STI in medical history (%, n = 1908) | 80.3 | 96.6 | 59.4 | 81.1 |
Chlamydia trachomatis (%, n = 2148) | 39.8 | 42.6 | 30.9 | 52.1 |
Hepatitis B (%, n = 2144) | 11.0 | 16.7 | 4.0 | 5.7 |
Hepatitis C (%, n = 2145) | 8.6 | 15.0 | 1.2 | 1.8 |
Mycoplasma genitalium (%, n = 2139) | 6.9 | 5.8 | 5.8 | 14.2 |
Neisseria gonorrhoeae (%, n = 2188) | 46.3 | 48.6 | 37.9 | 58.9 |
Treponema pallidum (%, n = 2155) | 40.9 | 55.4 | 20.8 | 33.7 |
Report of STI-related clinical symptoms in the last four weeks (%; n=;642) | 32.2 | 29.1 | 37.7 | 33.0 |
Most participating MSM reported to be single (44.8%) or to live in an open relationship with an agreement for sex with others (32.6%). Most stated to have met their sex partners on the internet (77.6%), in bars (36.8%) or in saunas (28.4%). The proportion of singles and MSM in open relationships was higher in HIV−/PrEP+ (96.8%) than in HIV−/PrEP- and HIV+ MSM (82.9 and 76.7%, respectively). 44.9% of all participants reported more than five male sex partners during the last 6 months, the proportion was higher in HIV−/PrEP+ (79.8%) than in HIV−/PrEP- (46.1%) and HIV+ (36.4%). Condomless anal intercourse (CAI, insertive and/or receptive) was reported by 73.2%, and more frequently from participating MSM reporting more than five sex partners (84.6%) than from MSM reporting one to four sex partners (66.5%), and more frequently from HIV−/PrEP+ (91.8%) than from HIV−/PrEP- (67.3%) and HIV+ MSM (73.1%).
The most frequently used risk reduction strategies to avoid HIV-infection when not using condoms were to ask the partner for his HIV-status (40%), only to have sex with HIV+ partners if they have an undetectable viral load (26.2%), only to have sex without a condom in a monogamous relationship (20.3%) and to use PrEP (15.6%).
The mainly reported substances used in the context of sexual encounters within the last 6 months were alcohol (80.6%), Poppers (53.9%), Viagra/Cialis (33.9%), and Cannabis (31.9%). 43.5% of all participants reported to use so called party drugs (defined as Cocaine, Crystal Meth, Ecstasy, GBL/GHB, Mephedron/Spice, Poppers and Speed) in the context of sexual encounters within the last 6 months; the use of party drugs was higher in HIV−/PrEP+ (64.4%) than in HIV−/PrEP- (39.6%) and HIV+ MSM (42.9%). The detailed population characteristics are summarized in Table
1.
HIV- participants were significantly younger than HIV+ MSM (median 35 IQR [30–43] vs. 44 [35–52], p < 0.01) and less likely to be born in Germany (67.2% vs. 80.8%, p < 0.01), but they were more likely to have acquired university-entrance diploma (74.6% vs. 54.4%, p < 0.01). The median number of male sex partners was significantly higher in HIV- MSM than in HIV+ (6 [3–15] vs. 4 [1–10], p < 0.01). There was no difference in having sex without using condoms in the last 6 months (73.1% vs. 73.4%, p = 0.88). The proportion of reported insertive condomless anal intercourse (CAI) did not differ between HIV- and HIV+ MSM (58.4% vs. 56.8%, p = 0.460). HIV- participants reported more insertive condomless oral intercourse (COI) (90.0% vs. 83.9%, p < 0.05) and receptive COI (86.0% vs. 76.1%, p < 0.05), but less receptive CAI (52.8% vs. 63.7%, p < 0.05). The use of party drugs did not differ between both groups (44.2 vs. 42.9%, p = 0.56). The proportion of participants with a STI history was significantly lower in HIV- participants (64.0 vs. 96.6%, p < 0.01). The proportion of clinical symptoms among positive STI-tested participants did not differ between both (35.4 vs. 29.1%, p = 0.08).
Regarding sociodemographics HIV−/PrEP- and HIV−/PrEP+ did not significantly differ. The differences between HIV+ and HIV- participants are described above. HIV−/PrEP+ reported the highest number of male sex partners (median 11 IQR [6–25]) and the highest proportion of sex without using condoms (91.8%), including insertive and receptive CAI (78.4, 73.8%) and COI (94.0, 88.7%). Also they reported to more frequently use party drugs (64.4%). The report of symptoms in positive tested participants was highest in HIV−/PrEP- (37.7%), followed by HIV−/PrEP+ (33.0%) and HIV+ (29.1%). The proportion of a previous STI was highest in HIV+ MSM (96.6%), followed by HIV−/PrEP+ (81.1%) and lowest in HIV−/PrEP- (59.4%).
Prevalence of CT, MG, NG, and TV
All together 30.1% (693) of all participants were tested positive for at least one of the tested STI (for specific prevalences, see Table
2), MG was the most prevalent pathogen (17.0%), TV was diagnosed only in 2 participants (Table
2).
Table 2
Prevalence of Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium and Trichomonas vaginalis, by pathogen and anatomical location
Any site | 693 | 30.1 | 28.2–32.0 | 227 | 9.9 | 8.7–11.1 | 205 | 8.9 | 7.8–10.1 | 391 | 17 | 15.5–18.6 | 2 | 0.1 | 0.01–0.3 | 117 | 5.1 | 4.2–6.0 |
Pharynx | 192 | 8.3 | 7.2–9.5 | 26 | 1.1 | 0.7–1.6 | 110 | 4.8 | 3.9–5.7 | 66 | 2.9 | 0.2–0.3 | 0 | 0 | 0 | 48 | 2.1 | 1.5–2.7 |
Rectum | 503 | 21.8 | 20.2–23.6 | 178 | 7.7 | 6.7–8.9 | 133 | 5.8 | 4.8–6.8 | 265 | 11.5 | 10.2–12.9 | 2 | 0.1 | 0.01–0.3 | 102 | 4.4 | 3.6–5.3 |
Urine | 192 | 8.3 | 7.2–9.5 | 45 | 2.0 | 1.4–2.6 | 32 | 1.4 | 0.9–1.9 | 124 | 5.4 | 4.5–6.4 | 0 | 0 | 0 | 48 | 2.1 | 1.5–2.7 |
Multiple sites | 170 | 7.4 | 6.3–8.5 | 63 | 2.7 | 2.1–3.5 | 91 | 3.9 | 3.2–4.8 | 99 | 4.3 | 3.5–5.2 | 0 | 0 | 0 | 72 | 3.1 | 2.4–3.9 |
16.9% (117) of participants were tested positive for more than one pathogen, of those 35.9% [
34] for CT/MG, 28.2% [
33] for CT/NG, 23.9% [
28] for NG/MG, and 12.0% [
14] for CT/MG/NG.
50.6% (351) of all diagnosed STI were solely manifested rectal, 11.1% (77) pharyngeal, 13.7% (95) urethral, and 24.5% (170) of all infections were manifested in more than one anatomical location. While for CT and MG the prevalence was lowest for pharyngeal infections, for NG the prevalence for pharyngeal infections was higher than for urogenital infections (Table
2). Rectal MG exhibited the highest prevalence (11.5%) of all diagnosed STI.
Independent risk factors for STI
The final multivariable regression model on the effect of the three risk groups on being tested positive for at least one STI included age, city of testing and country of birth. Being HIV+ (OR 1.7, 95%-CI 1.3–2.2) or using PrEP (OR 2.0, 95%-CI 1.5–2.7) were independent risk factors, also partly younger age groups (Table
3).
Table 3
Independent risk factors for STI-acquisition regarding risk groups, bivariable and multivariable logistic regression (n = 2145)
Risk group (ref. HIV−/PrEP-) |
HIV+ | 1.33 | 1.08–1.64 | 0.01 | 1.7 | 1.34–2.16 | 0.00 |
HIV−/PrEP+ | 2.03 | 1.51–2.70 | 0.00 | 1.98 | 1.46–2.66 | 0.00 |
Demographics |
Age groups (ref. 40–49 yrs) |
18–24 yrs | 0.82 | 0.51–1.31 | 0.40 | 1.08 | 0.64–1.79 | 0.78 |
25–29 yrs | 1.46 | 1.08–1.96 | 0.01 | 1.48 | 1.08–2.04 | 0.02 |
30–39 yrs | 1.26 | 1.00–1.59 | 0.05 | 1.16 | 0.90–1.48 | 0.24 |
50–59 yrs | 0.69 | 0.51–0.91 | 0.01 | 0.67 | 0.50–0.91 | 0.01 |
> 59 yrs | 0.45 | 0.25–0.81 | 0.01 | 0.5 | 0.28–0.91 | 0.02 |
City of testing (ref. Cologne) |
Aachen | 0.48 | 0.36–0.91 | 0.02 | 0.68 | 0.42–1.09 | 0.11 |
Berlin | 1.2 | 0.88–1.63 | 0.26 | 1.22 | 0.87–1.70 | 0.24 |
Bochum | 0.58 | 0.39–0.85 | 0 | 0.66 | 0.44–1.0 | 0.05 |
Dortmund | 0.77 | 0.46–1.28 | 0.31 | 0.91 | 0.54–1.54 | 0.74 |
Dresden | 1.00 | 0.61–1.62 | 0.99 | 1.07 | 0.65–1.77 | 0.79 |
Munich | 1.19 | 0.82–1.73 | 0.94 | 1.15 | 0.78–1.71 | 0.48 |
Nurnberg | 1.56 | 0.73–3.32 | 0.25 | 1.53 | 0.69–3.40 | 0.29 |
Stuttgart | 0.99 | 0.66–1.49 | 0.96 | 1.03 | 0.67–1.59 | 0.88 |
Country of birth (ref. Germany) |
Other country | 1.24 | 1.01–1.51 | 0.04 | 1.06 | 0.85–1.32 | 0.60 |
The regression model on the effect of HIV in MSM not using PrEP (HIV+ MSM vs. HIV−/PrEP- MSM) on being tested positive for at least one STI included age, city of testing and country of birth and showed HIV+ as independent risk factor (OR 1.8, 95%-CI 1.4–2.3; Additional file
2: Table S1). The likewise model on the effect of PrEP use in HIV- MSM included the same variables and showed PrEP use as independent risk factor (OR 2.0, 95%-CI 1.5–2.7; Additional file
1: Table S2).
The regression model on the influence of sexual behavior on being tested positive for at least one STI included the variables age group, city of testing, number of male sexual partners, sex without condom, and the use of party drugs. Independent risk factors were having more than five male sex partners within the last 6 month (OR 1.6, 95%-CI 1.2–2.0), having sex without using a condom within the last 6 month (OR 2.1, 95%-CI 1.6–2.8) and the use of party drugs within the last 6 months (OR 1.6, 95%-CI 1.3–2.0; Table
4). Younger age was an independent risk factor, partly significant, partly nearly reaching level of significance (Table
4).
Table 4
Independent risk factors for STI-acquisition regarding sexual behaviour, bivariable and multivariable logistic regression (n = 1864)
Demographics |
Age in groups (ref. 40–49 yrs) |
18–24 yrs | 0.82 | 0.51–1.31 | 0.40 | 1.10 | 0.64–1.85 | 0.33 |
25–29 yrs | 1.46 | 1.08–1.96 | 0.01 | 1.45 | 1.02–2.07 | 0.04 |
30–39 yrs | 1.26 | 1.00–1.59 | 0.05 | 1.28 | 0.97–1.67 | 0.08 |
50–59 yrs | 0.69 | 0.51–0.91 | 0.01 | 0.72 | 0.51–1.01 | 0.06 |
> 59 yrs | 0.45 | 0.25–0.81 | 0.01 | 0.60 | 0.30–1.17 | 0.13 |
City of testing (ref. Cologne) |
Aachen | 0.77 | 0.36–0.91 | 0.02 | 0.89 | 0.53–1.50 | 0.66 |
Berlin | 1.20 | 0.88–1.63 | 0.26 | 1.10 | 0.76–1.60 | 0.60 |
Bochum | 0.58 | 0.39–0.85 | 0 | 0.72 | 0.45–1.13 | 0.16 |
Dortmund | 0.77 | 0.46–1.28 | 0.31 | 1.50 | 0.82–2.74 | 0.19 |
Dresden | 1 | 0.61–1.62 | 0.99 | 1.84 | 1.03–3.29 | 0.04 |
Munich | 1.19 | 0.82–1.73 | 0.94 | 1.37 | 0.89–2.11 | 0.15 |
Nurnberg | 1.56 | 0.73–3.32 | 0.25 | 1.71 | 0.68–4.30 | 0.25 |
Stuttgart | 0.99 | 0.66–1.49 | 0.96 | 1.24 | 0.77–1.98 | 0.38 |
Sexual behaviour during the last 6 months |
Number of male sex partners (ref. 0–5) |
> 5 | 2.12 | 1.74–2.58 | 0.00 | 1.56 | 1.25–1.96 | 0.00 |
Sex without condom (ref. no) |
yes | 2.70 | 2.13–3.42 | 0.00 | 2.09 | 1.58–2.76 | 0.00 |
Use of party drugs (ref. no) |
yes | 2.68 | 2.02–3.57 | 0.00 | 1.62 | 1.30–2.01 | 0.00 |