The 50-year federal prison sentence of a Miami executive who operated the nation’s biggest mental-health clinic scam against Medicare has been upheld by an appeals court.

The 2011 sentencing of Lawrence S. Duran, 51, the former owner of the Miami-based American Therapeutic Corp. chain, was the longest in the history of Medicare fraud cases.

The 11th U.S. Circuit Court of Appeals found last week that the sentence by U.S. District Judge James Lawrence King was “reasonable” in light of the size of Duran’s scheme: more than $200 million.

The appeals court also upheld King’s 35-year sentence of Duran’s live-in partner, Marianella Valera, 42, who was ATC’s chief executive officer and a licensed therapist.

“The sentences are harsh, but the offenses were grave,” the Atlanta appeals court ruled. “So goes the world of crime and punishment.”