1. Kaiser Permanente Colorado; Institute for Health Research; Denver Colorado USA
2. Division of General Internal Medicine, Department of Medicine and Division of Substance Dependence, Department of Psychiatry; University of Colorado School of Medicine; Aurora CO, USA
3. Denver Health Medical Center; Denver CO USA
4. University of Washington School of Public Health; Department of Health Services; Seattle USA
5. Undergraduate Medical Education, University of Colorado School of Medicine; Aurora CO USA
6. Division of General Internal Medicine, Massachusetts General Hospital; Harvard Medical School; Boston MA USA
7. Boston Health Care for the Homeless Program; Boston MA USA
8. Department of Biostatistics and Informatics, Colorado School of Public Health; University of Colorado Denver; Aurora CO USA