[1] Vanderbilt Univ, Sch Med, Div Neonatol, Pediat & Hlth Policy, Nashville, TN 37212 USA
[2] Vanderbilt Univ, Sch Med, Dept Hlth Policy, Nashville, TN 37212 USA
[3] Tennessee Dept Hlth, Nashville, TN USA
[4] Vanderbilt Univ, Med Ctr, Dept Hlth Policy, Nashville, TN USA