Here's how 'Obamacare' covered Americans with pre-existing conditions. What happens next?

One of the most popular parts of the Affordable Care Act guarantees health insurance for people with “pre-existing conditions” – medical problems such as HIV, Alzheimer’s disease, and epilepsy. Before the law took full effect in 2014, people with these conditions were routinely denied coverage.

Back then, insurers in 45 states and the District of Columbia could reject individual applicants — those who didn’t receive insurance through an employer or the government — on the basis of health; five states didn’t allow so-called “medical underwriting”.

Insurers’ rationale for rejecting people with pre-existing conditions was straightforward: sick people are more expensive to cover than the healthy and young.

"Someone with cancer is going to make, let's say, a hundred times the health insurance claims of someone in good health in a year," said Karen Pollitz, a senior fellow studying health reform at the Kaiser Family Foundation. A study Pollitz authored last year found that, in 2011, the sickest 10% of Americans accounted for almost two-thirds of health spending in the population.

In all, at least 30 pre-existing conditions would automatically disqualify people from major health insurance plans before the Affordable Care Act, according to another recent study by the Kaiser Family Foundation. Even when applicants had less severe conditions, such as high cholesterol, insurers often sought to limit costs by charging higher premiums, increasing deductibles or modifying benefits.

The Affordable Care Act – or “Obamacare” as it’s affectionately and not-so-affectionately known – required insurers to cover everyone who applied on the individual market, regardless of their health. Insurers couldn’t limit coverage or charge more for the plans, either.

The law also required insurers to cover a wider range of benefits than before. These included annual doctor’s visits, preventive screenings, prescription benefits and mental-health care – often without charge.

As Donald Trump and congressional Republicans begin to dismantle the Affordable Care Act, the fate of such protections – and the millions of Americans who rely on them – is uncertain.

President Trump has signalled he would like to keep coverage for people with pre-existing conditions. Shortly before taking office, Trump told the Washington Post that a Republican healthcare plan would provide “insurance for everybody”.

But covering “everybody” is expensive — both for insurers and the government.

The Affordable Care Act spread the costs of covering sick people by requiring everyone, even the healthy, to buy insurance. This “individual mandate” meant that people couldn’t just wait until they got sick to get care. The law also provided subsidies to help low-income Americans afford coverage.

Here’s a simplified version of how it worked: