An analysis of a cohort of people diagnosed with syphilis in British Columbia found an association between HIV and ocular cases of the sexually transmitted infection (STI)—those affecting the eyes. Ocular syphilis, which can damage eyesight, was also associated with the earlier stages of the STI.

Syphilis has been resurgent around the world in recent years, including in the United States, in particular among HIV-positive men who have sex with men (MSM). Research has identified an association between ocular syphilis and new HIV infections.

Publishing their findings in Clinical Infectious Diseasees, a research team led by Troy Grennan, MD, a clinical assistant professor at the University of British Columbia, analyzed 6,716 cases of syphilis diagnosed in British Columbia between 2010 and 2018, focusing on the 66 (0.98%) cases of ocular syphilis. They matched the ocular syphilis cases with a control group of 244 people with non-ocular syphilis matched for age group, sex and date of diagnosis.

In 2010, 0.48% of overall syphilis cases were ocular, a figure that increased to 0.83% by 2018.

The median age of those with ocular syphilis was 49.5 years old. A total of 87.8% of the individuals were male, and 54.6% were MSM. A total of 48.5% of those with ocular syphilis had HIV, compared with 26.4% of the control subjects.

The most common eye-related diagnosis was panuveitis, or inflammation of the middle layers of the eye, seen in 42.5% of the ocular syphilis cases.

After adjusting the data to account for various differences between the study cohort members, the researchers found that compared with having a late, latent case of the STI, having an early stage of syphilis, including primary or secondary syphilis, was associated with a 4.95-fold greater likelihood of having ocular syphilis, and having early latent syphilis was linked to a 4.29-fold greater likelihood of ocular syphilis.

Having HIV, compared with not having the virus, was associated with a 2.16-fold greater likelihood of having ocular syphilis.

“Ocular syphilis increased over the study period, both in absolute numbers and as a proportion of all syphilis cases, a finding consistent with other jurisdictions,” the study authors concluded. “These findings highlight the importance of vigilance for ocular syphilis, to avoid diagnostic and treatment delays.”

To read the study abstract, click here.