Table 2.
Baseline characteristics of the study population, N (%) unless indicated otherwise, stratified by database
| EMIS | SMON | SOAP | ||
|---|---|---|---|---|
| Age | Range | 14–87 | 14–86 | 16–76 |
| Mean (SD) | 39.81 (12.34) | 38.36 (13.51) | 37.99 (11.66) | |
| Median | 40 | 39 | 38 | |
| Residence | Amsterdam | 1019 (26.9) | 706 (19.6) | 1433 (37.7) |
| Rotterdam | 185 (4.9) | 175 (4.9) | 215 (5.7) | |
| The Hague | 167 (4.4) | 138 (3.8) | 170 (4.5) | |
| Utrecht | 122 (3.2) | 144 (4.0) | 93 (2.4) | |
| Other areas | 1881 (49.7) | 2280 (63.3) | 1785 (47.0) | |
| Missing | 413 (10.9) | 159 (4.4) | 104 (2.7) | |
| Ethnicity | Dutch | 2833 (74.8) | 3131 (86.9) | 3114 (81.9) |
| Not Dutch | 849 (22.4) | 458 (12.7) | 679 (17.9) | |
| Missing | 105 (2.8) | 13 (0.4) | 7 (0.2) | |
| Not Dutch | Turkey, North Africa | 17 (2.0) | 23 (5.0) | 47 (6.9) |
| Specified | Surinam, Netherlands Antilles | 32 (3.8) | 68 (14.9) | 95 (14.0) |
| Eastern Europe | 103 (12.1) | 21 (4.6) | 73 (10.8) | |
| Sub-Sahara Africa | 26 (3.1) | 11 (2.4) | 15 (2.2) | |
| Central and South America | 86 (10.1) | 22 (4.8) | 85 (12.5) | |
| Rest of Europe | 418 (49.2) | 211 (46.1) | 64 (9.4) | |
| Asia | 83 (9.8) | 74 (16.2) | 69 (10.2) | |
| N. America, Canada, Oceania | 84 (9.9) | 28 (6.1) | 231 (34.0) | |
| Number | 1–2 | 527 (13.9) | 585 (16.2) | 940 (24.7) |
| of | 3–5 | 674 (17.8) | 796 (22.1) | 1107 (29.1) |
| Partners | 6–10 | 570 (15.1) | 512 (14.2) | 740 (19.5) |
| 11–20 | 504 (13.3) | 392 (10.9) | 388 (10.2) | |
| 21–50 | 437 (11.5) | 236 (6.6) | 250 (6.6) | |
| >50 | 250 (6.6) | 49 (1.4) | 338 (8.9) | |
| Missing | 825 (21.8) | 1032 (28.7) | 37 (1.0) | |
| CLP | Yes | 1485 (39.2) | 753 (20.9) | 872 (22.9) |
| Missing | 851 (22.5) | 2363 (65.6) | 2321 (61.1) | |
| Substances | Alcohol | 3469 (91.6) | 2521 (72.1) | – |
| w/i 6 mo. | Poppers | 1640 (43.3) | 1348 (38.6) | – |
| Viagra | 1081 (28.5) | 932 (26.7) | – | |
| Cannabis | 905 (23.9) | 634 (18.1) | – | |
| Ecstasy | 708 (18.7) | 502 (14.4) | – | |
| Speed | 249 (6.6) | 157 (4.5) | – | |
| Methamphetamine | 81 (2.1) | 57 (1.6) | – | |
| GHB | 493 (13.0) | 408 (11.7) | – | |
| Cocaine | 375 (9.9) | 257 (7.4) | – | |
| Missing | 0 (0.0) | 107 (3.0) | – | |
| STI | Gonorrhoea | 194 (5.2) | 174 (5.0) | 322 (8.5) |
| Chlamydia | 260 (7.0) | 235 (6.7) | 362 (9.5) | |
| Syphilis | 122 (3.3) | 136 (3.9) | 120 (3.2) | |
| Hepatitis B | 435 (11.5) | 383 (11.0) | 144 (3.8) | |
| Hepatitis C | 136 (3.6) | 56 (1.6) | 0 (0.0) | |
| Herpes | 28 (0.7) | 34 (1.0) | 22 (0.6) | |
| Warts | 102 (2.7) | 81 (2.3) | 90 (2.4) | |
| Other STI | – | 25 (0.7) | 20 (0.5) | |
| (Skin) diseases | – | 2 (0.1) | 108 (2.8) | |
| Missing Mean | 32 (0.8) | 107 (3.0) | 2 (0.1) | |
| HIV status | HIV+ | 589 (15.6) | 414 (11.5) | 679 (17.9) |
| HIV– | 2408 (63.6) | 2164 (60.1) | 2512 (66.1) | |
| Never tested | 774 (20.4) | 864 (24.0) | 490 (12.9) | |
| Missing | 16 (0.4) | 160 (4.4) | 119 (3.1) |
CLP Condom use with last sexual partner, GHB gamma-hydroxybutyraat, mo. months, STI sexually transmitted diseases, HIV human immunodeficiency virus