WHO warned on Tuesday of a “fierce competitive landscape” for health care savings accounts and said its work had “not yet been completed”.
The UN health agency also warned of “significant health costs” from an ageing population, as well as “uncertainties” over whether and how the new health savings accounts would work in practice.
The WHO also warned that there was no evidence to date that health savings policies had reduced health care costs.
The Geneva-based agency is the UN’s chief medical adviser.
Its report is the latest in a series of warnings that health care spending will increase in coming years.
It says the global economy will become more unequal, and that many people will need financial assistance to care for themselves or their families.
The report, published ahead of the World Economic Forum’s annual conference in Davos, is an update of a report published in 2014.
That report predicted a rapid increase in health spending, with healthcare spending expected to rise from $6 trillion in 2030 to $19 trillion in 2050.
The UN agency also said that the “costs of healthcare are a growing source of uncertainty and frustration”.
“The health savings market is expected to grow to more than $1 trillion by 2030,” it said.
“There is a growing concern that health spending will remain too high as population growth accelerates and economic growth slows, with health costs expected to continue to rise as healthcare spending increases.”
It said that despite progress on reducing healthcare costs, “there are no clear indications” of how these savings accounts might work.
The new accounts are designed to be used to cover health costs that have not yet been covered by insurance.