Among states, Pennsylvania fared the worst, according to HealthPocket, with 32 percent of insurance applicants paying more than insurers first quoted.
"Consumers cannot objectively compare health insurance premiums prior to application because insurers base their initial rates on the healthiest applicants, and for many these rates would not apply,” said Kev Coleman, head of research and data at HealthPocket, in a statement.
"When insurers wait until an application is reviewed to reveal the true monthly premium, it is impossible for consumers to know what health insurance plan is the least expensive for their circumstances," Coleman said.
The analysis involved 10,817 health plans for individuals and families under age 65.
Residents of Maine, Massachusetts, New Jersey, New York, Oregon, Vermont and Washington saw no notable increase in premium costs, HealthPocket found.