| Characteristic | Frequency, n (%) |
|---|---|
| Sex | |
| Male | 36 (84) |
| Female | 7 (16) |
| Age, years | |
| 16–25 | 11 (26) |
| 26–35 | 7 (16) |
| 36–45 | 7 (16) |
| 46–55 | 8 (19) |
| >55 | 10 (23) |
| (Half) Year of diagnosis | |
| 1 July 2013–31 Dec 2013 | 5 (12) |
| 2014 | 10 (23) |
| 2015 | 9 (21) |
| 2016 | 11 (26) |
| 2017 | 8 (19) |
| 1 Jan 2018–31 July 2018 | 0 |
| HIV status | |
| Positive | 8 (19) |
| Co-infection | 3 (7) |
| Not recorded | 32 (74) |
| Stage of disease | |
| Primary | 10 (23) |
| Secondary | 6 (14) |
| Early latent | 3 (7) |
| Late latent | 6 (14) |
| Neurosyphilis | 0 |
| Unknowna | 17 (40) |
| Missing data | 1 (2) |
| Follow-up | 39 (91) |
| Missing data | 4 (9) |
| Referral | 6 (15) |
| Sexually transmitted infection clinic | 3 (50) |
| Venereologist or internist | 3 (50) |
| Treated by GP | 33 (85) |
| 1x penicillin | 18 (55) |
| 3x penicillin | 15 (45) |
| According to guideline b | 28 (85) |
| Undertreated | 3 (9) |
| Overtreated | 2 (6) |
aUnknown stage of disease or possible serological scar, which is clinically the same as late latent stage and requires 3x penicillin treatment.b Based on the stage of disease the first choice treatment of syphilis consists of one or three penicillin injections. Undertreated is when one penicillin injection was given when three were recommended by the guideline, and vice versa for overtreated.