Managers braced for the last NHS league tables before the system is scrapped today warned that many hospitals may drop down the table, despite improvements.

Managers' organisation the NHS Confederation today voiced fears that some NHS trusts could lose the top three star status in the last round of ratings, due to be published tomorrow, leaving patients with the impression that clinical standards have fallen.

This is despite the fact that only a few indicators relate to the quality of care administered in a hospital.

Currently, the star ratings assessment process does not go into detail about the process of care or the quality of a particular operation.

The star ratings are a measure of effectiveness of the trust's management team rather than standards of clinical care, with the highest performers awarded three stars.

From next year, a new performance rating will replace the star system, encompassing a broader range of issues of concern to patients, backed by fewer inspections.

Watchdog the Healthcare Commission will assess performance by looking at how far a hospital has met the government's core national standards and targets, with the results published each autumn.

An NHS Confederation spokesman said tomorrow's ratings would fail to reflect the true nature of a hospital's care provision, setting up "a perverse situation" for trusts at a time when the patient choice agenda is being rolled out.

"We are glad they are being abolished," he said. "We think the star ratings are problematic. A trust may have got three stars last year and this year only get two, so a patient will look at that and assume the content of care provided by that hospital has got worse than last year.

"But that is not necessarily the case because the standards against which they are being judged have gone up and up."

The league tables were launched three years ago by the government in an attempt to address the variation in performance across NHS trusts. They were seen as a means of driving up standards and making managers more accountable to the public.

They rank the effectiveness of every NHS trust in England to give patients a sense of how well local health services are run. Acute hospitals are rated on up to 44 areas, for example, ranging from cancelled operations and waiting times, to cleanliness and staff morale.

But the days of the star rating system, first introduced by the then health secretary, Alan Milburn, were numbered after the chairman of the Healthcare Commission, Sir Ian Kennedy, last year criticised the system as too crude.

Sir Ian instigated a transformation of the assessment system to provide more relevant information to patients to help them choose where they would like be treated.

The move dovetails with the government's choice agenda being introduced later this year, which will allow patients to choose from one of five hospital providers to receive treatment.

The Patients Association welcomed the new system, which it believes will be more relevant for patients seeking to make informed choices about their care.

The association's chairman, Michael Summers, said the new system would be more "patient centred" and beneficial to people deciding where to have treatment.

"It may be that patients do not understand that some of these ratings have nothing to do with patient care," he said. "Sometimes it has to do with running financial affairs and patients do not understand that."

The first round of the new system will be published in September 2006.