The annual amount that people with type 1 diabetes spent on the drug rose from about $2,900 in 2012 to about $5,700 in 2016, according to a new analysis from the nonprofit Health Care Cost Institute (HCCI), CBS News reported.
Those are gross amounts and don't factor in the use of rebates or coupons, which can reduce costs for some people.
The cost of living rose 6.5 percent between 2012 and 2016.
A study published last year found that more than one-quarter of people with diabetes said they reduced their use of insulin due to the rising cost. Doctors warn against cutting back on insulin usage, CBS News reported.
"There has been a flurry of news reports sharing stories of individuals with diabetes rationing their insulin because they cannot afford higher and higher prices," according to HCCI.
"These anecdotes are consistent with findings of researchers documenting price increases on diabetic therapies, specifically insulin, over the last several years," the institute said.