“…[See these selected papers that describe trends in PWID or in HIV among PWID (Chatterjee et al, 2011; Cooper et al, 2008; Pouget, Friedman, Cleland, Tempalski, & Cooper, 2012; Tempalski et al, 2009, 2013; West et al, 2016); in services for PWID (Tempalski, Cleland, Chatterjee, Pouget, & Friedman, 2010); and predictors of service presence or coverage (Friedman et al, 2007; Tempalski et al, 2003, 2007, 2008). ] Instead, we briefly and selectively summarize some key findings from five of these papers that directly addressed the predictors of PWID population prevalence or HIV prevalence or incidence at the metropolitan level, and then discuss some implications of these findings.…”