Former President Bill Clinton in the ICU

Former President Bill Clinton

Former President Bill Clinton in the ICU

"He is improving, in good spirits, and is very grateful to the doctors, nurses, and staff who provide him with excellent care," his spokesperson said. Spokesman Angel Urena said the disease is not an infection linked to Covid.

"Former President Clinton was admitted Tuesday evening to UCI Medical Center for treatment," he said in a statement. "He is improving, in good spirits, and is very grateful to the doctors, nurses, and staff who provide him with excellent care." Clinton's doctors also issued a statement.

"He has been taken to hospital for close monitoring and taking antibiotics and intravenous fluids. Dr. . Albesh Amin and Lisa Bardak said in the statement. 

He complained of a urinary infection that spread into the bloodstream, a source familiar with the situation told NBC News on Friday. The source said Clinton was awake and agitated and that his wife, former Secretary of State Hillary Clinton, was at his side.

President Joe Biden told reporters Friday that Clinton "appears to be doing well, God willing," although the two have yet to communicate by phone.

A source close to Clinton said Thursday that he was in intensive care "as a precaution." The source said the hospital needed to isolate him and not because his care required it.

In 2004, Clinton bypassed surgery at New York-Presbyterian Hospital to redirect his blood supply to circumvent four severely blocked arteries, the New York Times reported. Clinton complained of chest pains and hard breath. The newspaper reported that a team of surgeons then discovered widespread signs of heart disease, with some of Clinton's arteries having more than 90 percent blockage.

Clinton returned to New York-Presbyterian Hospital in 2010 to undergo another heart operation, this time to have two coronary stents inserted.

Bill Clinton and Hillary Clinton were scheduled to attend a special Clinton Foundation event in California Thursday night.

Hillary Clinton went to the event to represent them both, according to a person close to Clinton, and then to be with her husband in Irvine, Orange County.