More than 20 million people in the United States gained coverage under the Affordable Care Act — the health overhaul that’s helped pushed uninsured rates to historic lows over the past few years.

President Barack Obama’s law also aimed to improve health by getting the poor and newly insured back into regular care and away from clinic visits or the emergency room.

Republican efforts to replace it are expected to increase the number of uninsured and may derail the steady push to bring people back into the fold — something doctors see as essential to cutting some costs and improving quality of life.

A recent projection from the nonpartisan Congressional Budget Office estimated the House bill would result in 23 million additional people going without insurance in 2026.