A Maryland firm that oversees the nation’s largest independent network of primary care medical practices is facing a whistleblower lawsuit alleging it cheated Medicare out of millions of dollars using billing software “rigged” to make patients appear sicker than they were.

The civil suit alleges that Aledade Inc.’s billing apps and other software and guidance provided to doctors improperly boosted revenues by adding overstated medical diagnoses to patients’ electronic medical records.

“Aledade did whatever it took to make patients appear sicker than they were,” according to the suit.