The great hope of Republicans and business to replace US healthcare insurance with a user-pays system is “in jeopardy” of failing because it underestimated the unpopularity of the schemes and failed to account for the way people use them, according to a study released on Tuesday.

In spite of short-term financial savings for companies, the survey by Towers Perrin, a risk and financial management consultancy, called into question the long-term sustainability of “consumer-driven” health plans because employees were unsatisfied and have little “confidence or competence as healthcare consumers”.

“Any consumer product that scored as low [as the consumer-driven health plans]...would be significantly retooled or pulled from the shelves,” it said.

The results are certain to increase the volume in the ever-louder US debate on how to reform healthcare in the face of soaring costs and uninsured citizens.

Most healthcare in America is provided by employer- and employee-funded health insurance. Two state-funded programmes for the poorest and for pensioners, Medicaid and Medicare, cover a quarter of the population, and 16 per cent have no health cover.

At least two significant Democratic contenders in the 2008 US presidential election race have proposed introducing national, presumably government-run, universal healthcare, but Republicans and a majority of the business community, have long backed mostly private-sector changes to healthcare provision.

Consumer-driven health plans, which have mostly been introduced in the past five years and cover only a minority of the population, make users pay directly using their own money and employer contributions kept in tax-advantaged savings accounts. Only catastrophic costs would be covered by an insurance component.

But the study called into question whether these plans could deliver long-term sustainable change to the US healthcare system.

It found that members of the plans were less satisfied than those with traditional health insurance. It concluded that employees were less comfortable with the financial risk exposure and less likely to understand their health plan, creating a dangerous “lack of trust” of their employers’ motives.

Significantly, only 44 per cent of respondents said the plans gave them affordable access to healthcare, compared with 63 per cent in traditional plans.

The key problem with the plans, the study said, was rooted in a naive assumption that people would automatically be confident purchasers of healthcare, as they would be in consumer product markets.

However, the study did not dispute the potential for consumer-driven plans to work and acknowledged positive signs, as consumers with a firm grasp of the plans “became better healthcare consumers”.