1 Michigan Bariatric Surgical Collaborative, USA; Center for Healthcare Outcomes and Policy, University of Michigan, Ann Arbor, USA. Electronic address: vitousc@med.umich.edu.
2 Michigan Bariatric Surgical Collaborative, USA; Center for Healthcare Outcomes and Policy, University of Michigan, Ann Arbor, USA; Department of Surgery, University of Michigan, Ann Arbor, USA.
3 University of Michigan Institute for Healthcare Policy and Innovation, Ann Arbor, MI, USA.
4 Michigan Bariatric Surgical Collaborative, USA.
5 University of Michigan Institute for Healthcare Policy and Innovation, Ann Arbor, MI, USA; VA Center for Clinical Management Research, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA; Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor, MI, USA.