“…Research on health services utilization patterns among chronic drug users has traditionally focused on individuals who are HIV positive, but some authors have more recently focused on the utilization patterns of drug users in general (Cherpitel, 2003;Falck, Wang, Siegal, & Carlson, 2003;French et al, 2000;Sterk, Theall, & Elifson, 2002;Zavala & French, 2003). Injection drug users (IDUs) living with HIV are less likely to use outpatient services than other chronic drug users (OCDUs-crack or cocaine users), but more likely to have frequent and longer hospitalizations (Celentano et al, 1998;Mauskopf et al, 1994;Solomon, Frank, Vlahov, & Astemborski, 1991;Solomon et al, 1998;Stein, 1990).…”