Irvine-based Alignment Healthcare LLC said today that it acquired Citizens Choice Health Plan for an undisclosed amount.

Citizens Choice, based in Cerritos, is a Medicare Advantage health plan with more than 1 million members spread across seven counties in California.

Medicare Advantage is a form of Medicare that’s delivered through HMOs.

Alignment works with hospitals, health plans and primary-care doctors’ groups to streamline medical care for chronically ill seniors who participate in Medicare Advantage. The company received $125 million in funding in April from Greenwich, Conn.-based General Atlantic LLC, a global investment firm with more than $17 billion under management.