Background Since 2010, infectious syphilis rates have risen dramatically in British Columbia (BC), Canada. We examined whether characteristics of a chlamydia (CT) or gonorrhea (GC) diagnosis were associated with a subsequent infectious syphilis diagnosis.

Methods All CT and GC diagnoses in BC from 2006 to 2017 were linked to infectious syphilis diagnoses in the subsequent 12-month period. A multivariable logistic regression model was used to identify factors associated with a subsequent infectious syphilis diagnosis and adjusted odds ratios (aOR) with 95% confidence intervals (CI) were reported.

Results Of the 133,264 CT/GC diagnoses, 819 (0.6%) linked to a subsequent syphilis diagnosis. Most were male (777/819, 94.9%) with a mean age of 36.1 years (standard deviation=11.2 years) and had ≥3 CT/GC diagnoses (419/819, 51.2%). At time of CT/GC diagnosis, 222 (27.1%) were living with HIV which increased to 245 (30.0%) at the time of a syphilis diagnosis. The odds of a subsequent syphilis diagnosis were greater among men (aOR=12.2, 95%CI: 8.4–17.7); older age groups of 25–29 years (aOR=1.5, 95%CI: 1.1–2.1), 30–39 years (aOR=2.4, 95%CI: 1.8–3.2), 40–59 years (aOR=3.7, 95%CI: 2.8–4.9), and ≥60 years (aOR=2.6, 95%CI: 1.3–5.0) when compared to age group 20–24 years; those living with HIV at time of CT/GC diagnosis (aOR=9.9, 95%CI: 7.6–12.9); those with a history of lymphogranuloma venereum (aOR=3.4, 95%CI: 2.3–5.2); those with a CT/GC diagnosis from 2012 onward (aOR=4.7, 95%CI: 3.7–5.9); and those with a history of 3 or 4 CT/GC diagnoses (aOR=13.2, 95%CI: 10.6–16.3) or 5+ CT/GC diagnoses (aOR=44.6, 95%CI: 34.8–57.1) when compared to those with 1 or 2 diagnoses.

Conclusion Characteristics of CT/GC diagnoses that were associated with a subsequent infectious syphilis diagnosis included male gender, older than age 24 years, co-infected with HIV, history of lymphogranuloma venereum, diagnosis of CT/GC from 2012 onward, and a history of 3+ CT/GC diagnoses.

Disclosure No significant relationships.