Previous Syphilis Not Associated With Neurocognitive Outcomes in People Living With Human Immunodeficiency Virus in Ontario, Canada

A retrospective cohort study of people living with human immunodeficiency virus in Ontario, Canada which found no association between previous syphilis and neurocognition. BackgroundAbout 40% to 60% of people living with human immunodeficiency virus (HIV) experience neurocognitive impairments, irrespective of antiretroviral status. We hypothesized that a history of syphilis or neurosyphilis would be associated with worse neurocognitive outcomes in this population.MethodsAmong health care-engaged people living with HIV in Ontario older than 16 years enrolled in the OHTN Cohort Study, neurocognitive outcomes were as follows: (1) self-reported Medical Outcome Study-HIV Health Survey 4-item cognitive scale; (2) average T score summary scores based on objective neuropsychological testing of complex attention, speed of processing, and learning/memory; and (3) global deficit score dichotomized into impaired/unimpaired neurocognitive status. Syphilis history was determined by laboratory data or chart review. Univariable and multivariable generalized linear mixed models assessed the association between each of: syphilis, number of episodes of syphilis, and years since syphilis diagnosis with these neurocognitive outcomes controlling for age, sex, race, education, income, years of HIV, nadir and most recent CD4 count, most recent HIV viral load, substance use, depression, and number of prior neurocognitive tests.ResultsOf 1288 eligible participants, 218 (16.9%) had a history of syphilis at baseline and an additional 53 were diagnosed during follow up for a total of 271 (21.0%) at the most recent visit. Of those with past infection at baseline, 179 (82.1%) had 1 and 39 (17.9%) had 2 or more episodes of syphilis. In longitudinal multivariable models, we observed no relationship between syphilis diagnosis or years since syphilis diagnosis and any of the neurocognitive outcomes.ConclusionsIn this sample, prior syphilis was not associated with worse neurocognitive outcomes over time according to self-reported scales or objective neuropsychological testing.