Latent classes of heroin and cocaine users predict unique HIV/HCV risk factors

Drug and Alcohol Dependence, 04/25/2012

Subpopulations of cocaine and heroin users differed in demographic classifications, HIV–risk behaviors, and Hepatitis C infection. All subpopulations included substantial numbers of HIV–positive individuals. Findings provide further evidence that non–injection drug users face significant infectious disease risk.


  • Latent class analysis identified sub-populations of 552 heroin and cocaine users in Baltimore, Maryland.
  • Using latent class regression, these classes were analyzed for associations with demographic characteristics, risky behaviors, Hepatitis C, and HIV.


  • Three classes were found: Crack/Nasal-Heroin users (43.5%), Polysubstance users (34.8%), and Heroin Injectors (21.8%).
  • Compared to Polysubstance users, Crack/Nasal-Heroin users were almost 7 times more likely to identify as Black (OR=6.97, 95% CI=4.35-11.2).
  • Sharing needles was over 2.5 times more likely among Polysubstance users than among Heroin Injectors (OR=2.66, 95% CI=1.49-4.75).
  • Crack/Nasal-Heroin users were 2.5 times more likely than Polysubstance users to exchange drugs for sex (OR=2.50, 95% CI=1.22-5.13).
  • Crack/Nasal-Heroin users were less likely than Heroin Injectors to have Hepatitis C (OR=0.10, 95% CI=0.06-0.18), but no significant differences were found for HIV.

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