–(BUSINESS WIRE)–Madeline S. Bell, former president and CEO of Children’s Hospital of Philadelphia (CHOP), is joining UnitedHealth Group’s (NYSE: UNH) Board of Directors, effective immediately. Madeline had a distinguished four-decade career at CHOP, where she started as a pediatric staff nurse in 1983. She spent eight years as CHOP’s chief operating officer from 2007 to 2015 before becoming president and CEO in 2015. She retired as CHOP’s CEO last month. Madeline holds a Master of Science de