His comments followed a warning from Bank of England Governor Mark Carney that the Brexit could lead to a "technical recession" in the UK.
"When the British economy sneezes, the NHS catches a cold," Stevens told the BBC on May 22, adding, "this would be a terrible moment for that to happen."
A few days after Stevens' comments, NHS Providers, a trade association representing more than 928,000 NHS staff members, released the results of a survey sampling leadership views. Forty-five chief executives and chairmen from the UK's hospital, ambulance, mental health and community trusts reported their thoughts on the impact of a potential Brexit.