WASHINGTON, April 16 (Reuters) – U.S. President Barack Obama signed a bill into law on Thursday that repairs the formula for reimbursing Medicare physicians after Congress, in rare bipartisan fashion, passed a fix earlier this week to prevent a 21 percent cut in doctors’ pay.

Sitting outside in the White House Rose Garden in his shirt sleeves, Obama said he was signing the bill now rather than waiting for a formal ceremony so it could go into force right away.

“This was a bipartisan effort,” Obama said, adding he hoped the practice of Republicans and Democrats working together would become a habit on Capitol Hill.

“Because we wanted to make sure doctors’ payments didn’t get cut off, I’m signing it now.”

The measure replaces a 1990s formula that linked Medicare doctor pay to economic growth, with a new formula more focused on quality of care. It also requires means-testing of Medicare beneficiaries so higher income people pay higher premiums.