1 Columbia University School of Nursing and Mailman School of Public Health, 560 West 168th Street, Office 624, New York, NY 10032, United States of America. Electronic address: lp2475@columbia.edu.
2 Department of Healthcare Management and European Observatory on Health Systems and Policies, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany. Electronic address: c.maier@tu-berlin.de.