NEVADA (Las Vegas) • Lamar Odom, a former National Basketball Association (NBA) champion who gained wider fame as the husband of reality TV star Khloe Kardashian, was in hospital after being found "unresponsive" at a Nevada brothel, authorities said on Tuesday.

He was stabilised at the Love Ranch, a legal brothel, and was to have been airlifted to a Las Vegas-area hospital. But the "stature" of the 2.08m former forward made it impossible to transport him by helicopter, a statement said.

The sheriff's office said an investigation was being conducted and gave no further details about Odom's condition or what caused the emergency.

A call to Sunrise Hospital in Las Vegas, where he was being treated, was not immediately returned.

The celebrity website TMZ reported that the 35-year-old was "fighting for his life".

He had been at the brothel for days and a woman there found him unconscious in his VIP suite.

The owner of the brothel, Dennis Hof, told the Los Angeles Times the former athlete had "wanted to get away from everybody, wanted to have fun". He told the newspaper that his staff said herbal Viagra was found in Odom's room.

Odom won NBA titles with the Los Angeles Lakers in 2009 and 2010 but last played in the league in 2013 for the Los Angeles Clippers.

He married Kardashian in 2009 in a splashy televised wedding but she filed for divorce in 2013.

In August that year, Odom, the subject of a string of news stories about alleged drug use and marital trouble, was arrested for drink driving.

Along with his NBA titles, he also earned Sixth Man of the Year honours as the NBA's top reserve in 2011, and won Olympic bronze with the United States in 2004.

His personal life, however, has been hit by tragedy. Estranged from his heroin-addict father at an early age, he was raised by his grandmother after his mother died of colon cancer when he was 12.

In 2006, his six-month-old son Jayden, one of three children with his one-time girlfriend Liza Morales, died of Sudden Infant Death Syndrome.

NBA star Dwyane Wade, once Miami Heat team-mates with Odom, was among many in the basketball fraternity who showed immediate concern. "I can't help but be up right now thinking about my ex-team-mate/friend LO... On my knees praying... please God let him pull through," the Heat guard wrote via Twitter.

AGENCE FRANCE-PRESSE, REUTERS