In the new version of the American Health Care Act (AHCA), the Republican bill to replace the Obama-era Affordable Care Act (ACA), one of the major points dividing the GOP conference was the treatment of pre-existing conditions.

What does the current law say?

The guarantee of health care coverage to people with pre-existing conditions has been one of the ACA's most popular features. Under the law, insurance companies cannot refuse to cover those with pre-existing conditions, that is, health issues that pre-date a new health insurance coverage. Insurers also can't charge more or refuse to pay for Obamacare "essential benefits" for any pre-existing condition. And, once enrolled in a plan, insurers can't deny such patients coverage or raise rates based solely on their health.

What about the new plan, the American Health Care Act?

The new GOP plan requires insurers to cover pre-existing conditions, and for those with continuous health care coverage, nothing will change. There are some caveats, though.

Insurers would be able to charge more to people with gaps in their insurance coverage. And a recent change, the MacArthur amendment, would allow states to waive some of the Obamacare requirements, including one that's relevant to pre-existing conditions. States that are granted such a waiver would allow insurers to set premiums based on health status -- current health, health history and other risk factors -- or in other words, pre-existing conditions.

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These states would also be able to set up high-risk pools to help reimburse the cost for insurers covering these consumers. The AHCA would provide funding for this purpose, though critics suggest it may not be enough.

What are pre-existing conditions?

States are likely to leave it to insurers to define pre-existing conditions, but prior to the ACA, pregnancy fell into that category, as well as mental disorders, and alcohol or drug abuse. The Kaiser Family Foundation compiled a list of what insurers called "declinable medical conditions" and risk factors that, prior to the ACA, could mean denial of coverage or higher premiums. Here are some of the conditions identified by individual market insurers in most states:

Alzheimers or dementia



Alcohol or drug abuse



Arthritis, fibromyalgia, or other inflammatory joint disease



Cancer within a period of time (the example cited by KFF is 10 years, "often other than basal skin cancer")



Cerebral palsy



Congestive heart failure



Diabetes mellitus



Emphysema



Epilepsy



Heart disease



Hepatitis



Kidney disease



Mental disorders - bipolar, or eating disorders, e.g.



Multiple Sclerosis



Muscular dystrophy



Obesity (severe)



Organ transplant



Paraplegia



Paralysis



Parkinson's disease



Pending surgery or hospitalization



Pneumocystic pneumonia



Pregnancy or expectant parent



Sleep apnea



Stroke



Transsexualism



Jennifer Tolbert, who is the Director of State Health Reform at the Kaiser Family Foundation, has read the AHCA and says at this point, it's not entirely clear how consumers with these conditions will be affected.

She said that in the past, individuals with pre-existing conditions in high-risk pools typically paid more than the average premium, "maybe 1.5 times as much," she said. But Tolbert also pointed out other problems, such as that pre-ACA, consumers faced waiting lists to get into high-risk pools or higher deductibles or insurance that didn't cover the medical problems stemming from the pre-existing condition.

She also pointed to another factor to consider, related to insurance coverage for people with pre-existing conditions: the AHCA would change the structure of the premium tax credits in the marketplaces, so older Americans, who are likely to be sicker, will probably see their tax credits go down.

This, combined with the rise in age rating (allowing seniors to be charged up to five times as much for coverage as younger Americans, rather than three times as much under the ACA) and the phase-out of the Medicaid expansion, is likely to result in more Americans losing their insurance coverage, according to Tolbert.