Modern Healthcare Illustration / Getty Images Massachusetts' largest physician group—currently squaring away a buyout deal with Optum—has tracked further into the red in its latest financial filings. Newton, Mass.-based Atrius Health, an organization with north of 700 physicians across 30 practices, lost $17 million on operations out of $514 million in revenue in the first quarter of 2021 ended March 31. That's even steeper than its $12.1 million operating loss on $2.2 billion in revenue in all of 2020. UnitedHealth Group plans to buy Atrius through its Optum subsidiary, according to the Boston Globe. Despite its size, Atrius is not immune to the lingering effects of the COVID-19 pandemic. The practice wrote in a note accompanying its financial statement that the crisis has lowered the number of patients with commercial insurance, decreasing its capitated member months. Atrius has also seen more of its patients switch to Medicaid, which has lowered its average capitation rate.