ABO and syphilis: In univariable analysis, a diagnosis of NG was associated with the composite ABO outcome (OR=4.39; 95% CI 1.24 to 15.59), as was a diagnosis of early untreated syphilis (OR=9.28; 95% CI 1.12 to 73.86) and HIV positivity (OR=2.99; 95% CI 1.06 to 8.44), but no statistically significant associations were observed for the individual ABO outcomes.