title: Psychobehavioral risk factors, substance treatment engagement and clinical outcomes as predictors of emergency department use and medical hospitalization.
abstract: OBJECTIVE
  Prior research on health care utilization after treatment for substance misuse disorders has not accounted for posttreatment clinical outcomes as well as putative confounds associated with both substance use and health care. This study examined the association of posttreatment health care utilization with treatment factors (program type and time in treatment) and baseline psychological/behavioral risk factors (smoking status and level of depressive, alcohol and drug dependence symptoms). The study also examined whether posttreatment clinical outcomes-participation in aftercare, Alcoholic Anonymous (AA) attendance, substance use, depressive symptoms and smoking- were associated with subsequent health care utilization.
  
  
  METHODS
  We analyzed predictors of posttreatment medical hospitalizations and emergency department (ED) use among 15,041 participants in a multistate treatment evaluation project conducted from 1987 to 1995.
  
  
  RESULTS
  Greater time in treatment reduced the likelihood of future hospitalizations and ED use, whereas clients in outpatient treatment were less likely to be hospitalized. Baseline measures of depressive, alcohol and drug dependence symptoms were each independently associated with subsequent health care use. Posttreatment aftercare participation reduced the likelihood of future hospitalization and ED use, whereas AA attendance also reduced the likelihood of hospitalization. In addition, posttreatment counts of depressive symptoms increased the likelihood of future hospitalization and ED use. Substance relapse increased the likelihood of subsequent ED use.
  
  
  CONCLUSIONS
  The study supports the public health importance of substance misuse disorders treatment, with greater treatment involvement associated with lower high-cost medical utilization. Treatment clinical outcomes-posttreatment relapse and depressive symptoms-partially mediate the effect of treatment on health care utilization.
authors.affiliation: Centers for Behavioral and Preventive Medicine, Coro Building, Suite 500, One Hoppin Street, Providence, RI 02903, USA. charles_neighbors@brown.edu
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Neighbors
authors.forename: William H
authors.initials: WH
authors.lastname: Zywiak
authors.forename: Robert L
authors.initials: RL
authors.lastname: Stout
authors.forename: Norman G
authors.initials: NG
authors.lastname: Hoffmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000436:Alcoholics Anonymous; D000553:Ambulatory Care; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology*; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004632:Emergency Medical Services; D005260:Female; D006304:Health Status; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012307:Risk Factors; D012959:Socioeconomic Factors; D019966:Substance-Related Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000534:rehabilitation*; D016896:Treatment Outcome