CBO said uninsured numbers "would be disproportionately larger among older people with lower
income — particularly people between 50 and 64 years old with income of less than 200 percent of the federal poverty level."
Of the estimated 23 million who would not have health insurance, the report predicted that 14 million people would lose Medicaid coverage, because of spending reductions in the GOP bill.
As for how much it would save consumers, the CBO said in certain states, premiums could drop by about twenty percent for a plan that has less coverage than what is currently offered to consumers.
But the report raised some concerns with a pivotal change made by Republicans, which allows states to get waivers from two key provisions of the Obama health law - one allowing states to peel back certain "Essential Health Benefits," the other allowing changes in how insurance companies can set premiums based on someone's health status, something known as "community rating."
"As a result, the nongroup markets in those states would become unstable for people with higher-than-average expected health care costs," the CBO report stated.
"That instability would cause some people who would have been insured in the nongroup market under current law to be uninsured," the report added.
Republicans found that somewhat hard to accept.
"I don't know how you can make it any more unstable than where we are right now," said Rep. Mark Meadows (R-NC).
"Most states are down to one carrier, and many of them are pulling out - I'm not sure how you make it less stable than that," he told reporters after hearing the headlines of the report.
The CBO also raised questions about how the plan would deal with those Americans who have pre-existing medical conditions.
"Over time, it would become more difficult for less healthy people (including people with preexisting
medical conditions) in those states to purchase insurance because their premiums would continue to increase rapidly," the report said.
Reaction to the plan broke - as one might expect - along party lines in the Congress.
"This CBO report again confirms that the American Health Care Act will lower premiums and the deficit," said House Speaker Paul Ryan.
"CBO continues to find that through our patient-focused bill, premiums will go down and that our reforms will help stabilize the market," said Reps. Greg Walden (R-OR) and Mike Burgess (R-TX).
Democrats were quick to denounce the plan.
"This Republican health care bill is a disaster," said Sen. Bill Nelson (D-FL).
"Trump Care will strip away healthcare coverage from 23 million Americans," said Rep. Lacy Clay (D-MO), as Democrats denounced it as nothing more than a tax cut for the wealthy.
"The Republican healthcare plan is a shame and a disgrace," said Rep. John Lewis (D-GA).
The release of the CBO numbers came as Senate Republicans continued to work behind closed doors on their own health care plan.
"We have to have the goal of lowering premiums for Americans," said Sen. Bill Cassidy (R-LA). "And it has to be credible coverage."
As of now, GOP Senators are only working with each other, and not trying to gain the votes of any Democrats.
It's a very small margin for error for the GOP, which can only afford to lose two of their 52 members - and then would have to rely on the tie breaking vote of Vice President Mike Pence.
"Regardless of any CBO score, it’s no secret Obamacare is collapsing under its own weight," said Sen. David Perdue (R-GA). "Doing nothing is not an option."
At this point, the health care bill approved by the House on May 4 still has not been sent to the Senate, as Republicans try to figure out that next step.
The House and Senate are not in legislative session next week, meaning any action by Republicans will be pushed into June.
The longer it takes to resolve health care legislation, the longer it will take to deal with the 2018 budget and President Trump's plans on tax reform.
You can read the full report from the Congressional Budget Office here.