Americans pay the most for health care, by far, out of all developed countries. But we don't have much to show for it in terms of health outcomes or access to care, according to a new OECD report.

Why it matters: As we debate reforms to our health care system, it's worth remembering that the U.S. is an outlier compared to other countries, which have figured out how to get cheaper care without sacrificing quality.

Almost all of the major health insurance companies are spending more on medical care this year than they have in the past, Axios' Bob Herman reports.

The big picture: Rising prices and more services for some sicker patients are among the many reasons why this is happening. That uptick in spending has freaked out Wall Street, even though insurers are still quite profitable.

Driving the news: Almost all of the eight major publicly traded insurers have shown their medical loss ratio — the percentage of premium revenues they're spending on medical claims — is rising this year.

• UnitedHealth Group, the largest insurer in the country, said its loss ratio was 82.4% in the third quarter this year compared with 81% in the same period a year ago.
• But these companies are handling billions of premium dollars, so any increase in medical claims equates to hundreds of millions of dollars in additional spending, which they don't want.

Between the lines: Medical loss ratios are often higher for health plans that cover more older adults, the disabled and the poor, because those groups typically need more care or are in the hospital more frequently.

But costs have been climbing in some commercial markets, too.

• Anthem executives admitted on their earnings call that the company is dumping some employers with workers who had medical needs and costs that were too high.
• CVS Health, which now owns Aetna, previously said some middle-market clients had employees that it thought were getting too many services and drugs.
• CVS "intensified our medical management in those geographies," an executive said on the earnings call.

The bottom line: Health insurance companies closely track their medical loss ratios and aim to hit those targets most often by charging higher premiums, denying care, forcing people to use lower-priced providers or declining to cover people they deem to be too expensive.

Privately insured people suffering from drug and alcohol addiction or mental health conditions pay more out-of-pocket for care and are more likely to see out-of-network providers than people with chronic physical health conditions, according to a new study in JAMA Network Open.

Between the lines: These costs prevent people from receiving care. The study used data from 2012–2017, a time frame during which the opioid epidemic was ravaging communities across the country.

By the numbers: Patients with mental health conditions spent $341 more on cost-sharing for out-of-network care than people with diabetes did.

• People with drug use disorders spent $1,242 more, and those with alcohol use disorders spent $1,138 more.

This disparity is partially a result of how infrequently behavioral health providers participate in insurance networks.

• "Combined with high demand and low rates of reimbursement, the workforce scarcity of behavioral health clinicians can represent the weakest component of health plan networks," the authors write.

Three cancer patients in the U.S. were the first to be safely injected with the gene editing tool CRISPR as a form of immunotherapy to fight their illness, AP reports.

Reality check: It's too soon to know whether the treatment will help, doctors say. The patients, who all failed multiple standard treatments, had varying results after two to three months, Axios' Marisa Fernandez writes.

• Two of the patients have multiple myeloma, a blood cancer, and the third has a sarcoma, cancer that forms in connective or soft tissue.
• The treatment deletes three genes that may be stopping the patients' cells from attacking the disease, and then adds ones to help them fight their cancer.
• 15 more patients will receive the treatment and doctors will gauge its safety and efficacy.

The bottom line: Researchers are hoping to use CRISPR to treat some genetic diseases, including its progress in treating sickle-cell anemia.

Millennials' health problems are on the rise, with future adverse consequences to both their own finances as well as the U.S. economy, according to a new report by the Blue Cross Blue Shield Association.

What they found: As millennials age, their health is declining faster than the previous generation's, and they're increasingly suffering from conditions like hypertension, high cholesterol, depression and hyperactivity.

• If the pattern doesn't change, millennials' mortality rate could climb by more than 40% compared to Gen-Xers when they were the same age.
• Under the worst-case scenario, their health care costs will be up to 33% higher than Gen-Xers' at the same age.
• Poor health could cost millennials more than $4,500 in annual per capita income.

The big picture: The biggest changes are in millennials' behavioral health. In 2017, accidental deaths, including overdoses and suicides, caused 60% of deaths among 25- to 29-year-olds, according to the CDC.

• "Millennial health patterns can cause declining millennial economic outcomes that in turn can cause further declines in millennial health. This represents a potentially vicious cycle resulting in even higher prevalence of depression and other behavioral health conditions over time," the report concludes.

My thought bubble: Our health spending is already on an unsustainable path. This absolutely does not help.

Go deeper: Today's health problems are tomorrow's health crises