Swiss hospital says it treated former Fiat Chrysler CEO Marchionne for more than a year

ZURICH (Reuters) - Former Fiat Chrysler Chief Executive Sergio Marchionne was having treatment for a serious illness for more than a year before his death on Wednesday, University Hospital Zurich (USZ) said on Thursday.

"Mr. Sergio Marchionne was a patient at USZ. Due to serious illness, he had been the recipient of recurring treatment for more than a year," the hospital said in a statement.

"Although all the options offered by cutting-edge medicine were utilized, Mr. Marchionne unfortunately passed away."

The announcement of the death of Marchionne, 66, one of theauto industry's most tenacious and respected CEOs, drew tributesfrom rivals and tears from his closest colleagues on Wednesday.

Marchionne had fallen gravely ill after what the company haddescribed as shoulder surgery at a Zurich hospital. He was replaced as chief executive last weekend after Fiat Chrysler (FCA) said his condition had worsened.

University Hospital Zurich declined to comment on Marchionne's illness, but said it deeply regretted his death and expressed its condolences to his family.

Fiat Chrysler had no immediate comment. Exor, the holding company of the Agnelli family which holds controlling stakes in FCA and Ferrari, both led by Marchionne until last Saturday, could not immediately be reached for comment.

(Reporting by John Revill; Additional reporting by Agnieszka Flak in Milan; Editing by Alexandra Hudson)