The team found that, in the states that allowed easy access to short-term health insurance, cancer-detection improvement trends were about 2.3% worse than in the states that banned use of short-term health insurance.

The analysis appears in a study published on the JAMA Network Open website.

The backdrop: The ACA preventive screening benefits rules apply to major medical plans set up since 2010, including self-insured employer health plans and high-deductible plans that are compatible with health savings accounts.

The rules require major medical plans to cover screenings for breast cancer, colon cancer and some other forms of cancer without imposing deductibles, copayments or coinsurance payment requirements on the patients.

Short-term health insurance policies do not have to meet the federal cancer screening requirements.

The federal government put a three-month duration on short-term health insurance before 2018, then let states set rules for allowing short-term coverage to stay in place for as long as 36 months.

The study: Yang's team analyzed the impact of short-term health insurance use by looking at diagnosis data for five easily detected, relatively easy-to-treat forms of cancer from the period from 2016 through 2020.

The team calculated how likely patients in each state were to learn they had cancer when the cancer was already at a late stage, meaning that the patient had a big tumor, the cancer had spread to the patient's lymph nodes or the cancer was spreading to the patient's entire body.

The team compared late-stage detection rates in the period from 2016 through 2018 with late-stage detection rates in the period from 2019 through 2020.

The late-stage detection rate fell to 31.11% in the states that banned short-term health insurance, from 33.77%, the team found.

In the states that allowed easy access to short-term health insurance, late-detection rates fell more slowly.

The overall late-stage detection rate fell to 36.03%, from 37.11%.

After the researchers adjusted the trends data for factors such as community income, they found that cancer detection improvement was 0.76 percentage points worse in the states with short-term health insurance restrictions.

The percentage points difference means that, in a state with easy access to short-term health insurance, people diagnosed with the cancers included in the study were 2.3% more likely to have late-stage cancer than if they'd lived in a state that banned short-term health insurance.

Implications: The researchers who conducted the study are skeptical about widespread use of short-term health insurance, but they only looked at one indicator of short-term health insurance value.

For workers who find that short-term health insurance is the only affordable option or, in some cases, the only option available outside the ACA open enrollment period window, a more relevant comparison might be late-cancer-detection rates for people with short-term health insurance and no insurance at all. The researchers did not include late-detect rate data for uninsured people.

The research might have more bearing on employers' and benefits advisors' questions about whether ACA benefits really pay for themselves, at least by improving the quality of care, or if the benefits simply make organized patients who get their screenings feel proud that they got their screenings.

Researchers have published many studies on the effects of the ACA preventive services benefits requirements on how likely patients are to get screenings, but many fewer studies on whether the requirements have affected health care outcomes.

Questions about the impact of the ACA preventive benefits requirements on care outcomes could get much more attention this summer, after the U.S. Supreme Court rules on the Braidwood preventive benefits case. The plaintiffs in the Braidwood case are employers who say that the strategy that the federal government uses to create the ACA preventive services benefits package, which relies partly on the advice of an expert panel with members who are not appointed by the president and confirmed by the Senate, is unconstitutional.

Related: Plans will keep preventive screening benefits even if Supreme Court zaps ACA provision, exec predicts

The Supreme Court has scheduled oral arguments on Braidwood for April 21.

If the Supreme Court sides with the plaintiffs and throws out some or all of the current ACA preventive services package requirements, employers and insurers may look harder at outcomes data when deciding what to do about their preventive services benefits.