Seroconversion to HBV associated with seroconversion to HIV in a cohort of intravenous drug misusers in Turin, Italy.

Between March 1986 and March 1994, the seroconversion to HBV associated to the seroconversion to HIV was investigated in 120 HIV seroconverters drawn from 2368 i.v. drug misusers screened for HIV, HBV and STDs. Among the 185 individuals susceptible to HIV and HBV at intake (41/120 HIV seroconverters and 144/364 HIV-negative controls), HBV seroconversion was associated with the seroconversion to HIV (p = 0.006) and history of more than 3 sexual partners per year (p = 0.000). Only the history of more than 3 partners per year remained associated with the HBV seroconversion in the conditional regression. The associated seroconversion to HIV and HBV was linked to the short period of i.v. drug injections (p = 0.032), history of more than 3 partners per year (p = 0.000) and more than 3 i.v. drug injections per day (p = 0.016). Compared to the seroconverters to HBV alone, the seroconverters to HBV and HIV were likely to have higher frequency of i.v. drug injection per day on univariate (p = 0.031) and multivariate analysis (p = 0.024). The seroconverters to both the viruses differed from the seroconverters to HIV alone in the year of drug debut (p = 0.045), short period of i.v. drug use (p = 0.048) and high frequency of injection per day (p = 0.008). The multivariate analysis confirmed only the association with high frequency of injection per day (p = 0.033). Higher risk of HIV seroconversion from the debut of i.v. drug use was observed in the subjects with concurrent HBV seroconversion (Log-Rank test: p = 0.0008).