UnitedHealth Group pays its own physician practices much more than it pays competing practices, a new study finds, reinforcing STAT’s own analysis on the subject and presenting fresh evidence that the conglomerate may be skirting a rule designed to curb health insurer profits. UnitedHealth’s insurance arm, UnitedHealthcare, pays practices under its UnitedHealth-owned Optum umbrella 17% more on average for common services than it pays non-Optum practices in the same region, according to the study...