The relationship between performance on the Shipley Institute of Living Scale (SILS) and hepatitis C infection among active injection drug users in Baltimore, Maryland

Background: Hepatitis C represents a significant public health problem, particularly among injection drug users. Other than injection drug practices, little is understood about individual level characteristics that may place some injection drug users at particularly high risk. Objectives: The current study sought to examine two associations among active, regular heroin injection drug users. The first was to determine whether there was an association between two scales from the Shipley Institute of Living Scale (SILS: a neuropsychological measure used to estimate cognitive impairment/intellectual functioning) and self-reported preexisting conditions independent of years of drug use. The second was to examine whether performance on the scales was associated with hepatitis C infection. Methods: Data from 260 HIV negative injection drug users from the Baltimore metropolitan region were used. Participants completed a risk behavior interview, brief neuropsychological battery, and were tested for Hepatitis C. Results: Findings indicated that scale performances varied by self-reported learning disabilities and attention deficit disorder. Poorer performance on one scale was statistically significantly associated with greater hepatitis C prevalence on the vocabulary scale, the discrepancy scale showed a statistical trend. Conclusions: Cognitive impairment measured among this sample of injection drug use was related to pre-existing conditions and hepatitis C independent of years of drug use. Such impairment may exist prior to initiation of use and increase vulnerability to poor health outcomes among injection drug users. Scientific Significance: This study highlights the need for interventions targeting a possible high risk subpopulation of injection drug users.