Family members say his wife, Indira Umarova, was shocked at her husband's severe weight loss and mental state when she visited him in jail on October 17.
Umarov was a successful businessman in Uzbekistan before he founded his coalition in 2005 to encourage national reform. He was arrested three years ago, found guilty of economic crimes, and sentenced to 10 years in jail before his sentence was reduced to seven years.
Rights groups and his relatives say his imprisonment is politically motivated and the charges fabricated, and also alleged recently that they'd seen signs during a visit that he'd been tortured during his detention.
Umarov's lawyer and family members fled Uzbekistan following his trial.