STLDpolicies come with coverage limits that also aren't allowed underthe ACA, meaning that consumers could end up on the hook forsubstantial bills.

People who turn to short-term, limited-duration health policiesrather than purchasing coverage required by the Affordable Care Actto meet standards in types and levels of care provided could be infor a rough ride, both financially and in terms of availablecare.

That's according to a research report from Milliman, which analyzedhow the expansion of STLD policies and other regulatory action haveaffected enrollment levels as well as how much patients pay inpremiums and medical costs.

Related: Idaho's 'enhanced short-term plans' a hit withconsumers

While healthier people might opt for STLD policies to save moneyon premiums, they get less bang for their buck and could be lettingthemselves in for substantially higher costs should they need toseek treatment. For instance, such policies aren't required tocover two of the essential health benefits mandated by theACA—prescription drugs and mental health benefits—and mostdon't.

In addition, most STLD policies come with coverage limits thatalso aren't allowed under the ACA, meaning that they could end upon the hook for substantial portions of any care they mayreceive.

The report highlights how dramatic this could be in thehypothetical case of a 'newly diagnosed lymphoma patient enrolledin an STLD policy in 2017 [who] could pay $16,800 more inout-of-pocket expenses, including premium and member cost-sharing,within six months following diagnosis than a lymphoma patientenrolled in an unsubsidized ACA-compliant policy."

And yet another drawback is that STLD policies aren't guaranteedrenewable, so should a policyholder be diagnosed with a newcondition while covered by a short-term policy, he may be leftuninsured at the end of the insurance period and have to wait forACA open enrollment or a special enrollment period just to getcoverage again. In the meantime, he could be stuck with substantialbills that will be his own responsibility to pay, not theinsurer's.

This makes for another hefty financial penalty (not to mentionthe mental stress). According to the report's authors, "We foundthat a patient who is denied STLD renewal three months following adiagnosis of lymphoma could be responsible for nearly $40,000 morein out-of-pocket expenses in the six-month period followingdiagnosis than if the same patient had been covered under anACA-compliant individual policy for the same period."

Then there are the effects of regulatory actions. UnsubsidizedACA individual market premiums are expected to increase byapproximately 4 percent in 2020 among states with full expansion ofSTLD policies thanks to such actions, according to the report, andwhile not all carriers broke down the causes of their projectedprice increases, most carriers that "explicitly adjustedACA-compliant premiums for the impact of the STLD plan expansionattributed a premium increase between 0.5 percent and 2 percent in2020" to that expansion.

Last but not least, the report estimates that 6 percent ofmembers in the ACA-compliant individual market will end up movingto nonminimum essential coverage, which includes people who chooseto forgo coverage and those who enroll in STLD policies, by2021—thanks to the selection dynamics created by STLD planexpansion and mandate repeal.

Read more: 

• Short-term health insurance could get aboost
• Idaho's bid to skirt Obamacare rejected by Trumpadministration
• House committee's bill would limit short-termhealth plans to 3 months