An increasing number of employers plan to offer only high-deductible plans to their workers.
U.S. middle-income households spent 51 percent more on healthcare in 2010 than a decade earlier, researchers say.
The study, conducted for AARP by Harriet Komisar of Georgetown University, showed over the past decade, healthcare growth was three times the rate of growth for all other spending on products and services.
"For both working-age and retirement-age middle class households, rising healthcare expenses are taking up a growing share of financial resources, leaving less for other priorities," the analysis said.
Healthcare spending per person reached $8,402 in 2010, a 72 percent jump from a decade earlier -- and nearly triple the 1990 average, Komisar said.
In 2011, one-third of Americans were in families facing a financial burden from medical bills, and 1-in-5 were in families having trouble paying those bills.
Companies shifted more health insurance costs to their workers over the last decade, more than doubling premiums for family coverage, from $1,787 in 2001 to $4,129 in 2011. This has contributed to reductions in health insurance coverage, the study said.
Health-related expenses absorbed a large share of incomes for people age 65 and older, and that share is projected to grow over time to 18 percent of future retirees' household income from 8 percent today.
Forty-one percent of middle-class people on the cusp of retirement, ages 56-62, are at risk of not being able to pay for basic living expenses and out-of-pocket health costs in their later years, the study said.
Long-term care services run from $22,000 a year for a part-time home-care assistant to $91,000 a year for nursing home care. These costs are not covered by Medicare, and few people purchase long-term care insurance, Komisar said.