Predictors of Frequent Emergency Room Visits in Patients with History of Illicit Drug Use.

a Denotes statistical significance. p b Defined as one or more housing status changes within a 1 year follow-up period from index ambulatory visit.c Reference group for these categories are patients without these health characteristics.d Health service utilization data collected over a 1 year follow-up time period from index ambulatory visit. Reference group was 0–2 visits per year.Predictors of Frequent Emergency Room Visits in Patients with History of Illicit Drug Use.