Figure 1. Model Structure Diagram.

A, Microsimulation model. The oval “Overdose” state represents a tunnel state; solid lines, transitions among health states; dotted lines, transitions between health states and overdose; and arrows, possible directions for state transitions. B, Decision tree model. We defined the overdose settings according to prior studies by the Rhode Island Department of Health,^18,19 where private settings include apartment or residence; semiprivate settings include hotel, motel, shelter, nursing home, hospital, prison, group home, assisted living, or treatment facility; and public settings include theater, concert, show, office, park, school, bar or restaurant, roadway, or cemetery. EMS indicates emergency medical services.