Some hospital trust boards are neglecting figures that may highlight serious care failings, leading to patient deaths, the Healthcare Commission has said.
Head of investigations Nigel Ellis said a small number failed to take mortality rates seriously. His warning comes ahead of publication of the regulator’s first report triggered by mortality figures.
The report reveals the commission has contacted nearly a fifth of all trusts in the space of a year following mortality rate alerts, with an investigation launched at just one.
Mr Ellis said: "We are seeing trusts that are not using this and in some areas not even understanding the significance. I don’t think the board discusses these issues in some trusts."
He said using the figures to trigger alerts had been a success and is expected to be continued by the Care Quality Commission.
But there is concern about making the figures public - particularly hospital standardised mortality ratios published by Dr Foster Intelligence.
The regulator's report says: "Although the publication of 'high level' hospital wide mortality rates is superficially appealing, we do not believe that this is the best way of providing meaningful information to the public."
Mr Ellis said: "We are not suggesting there should be a Top of The Pops or league table for trusts."
Academic debate on whether the rates reflect quality of care continues.
Birmingham University senior research fellow Mohammed A Mohammed, who wrote a report on the metric for NHS West Midlands, said their use in regulation was reasonable, but publication was "potentially misleading and unethical".
Sir Brian Jarman, head of Imperial College London's Dr Foster unit, said the ratios were still valid and the problem highlighted by Dr Mohammed did not make a significant difference.
NHS medical director Sir Bruce Keogh said: "The most important issue is that people are talking about measurement."
Wrightington, Wigan and Leigh foundation trust was alerted to its high mortality rates two years ago. It believes reducing the rate as its first priority has resulted in 200 fewer deaths over 10 months.
Medical director Chris Chandler said: "We improved basic care, dramatically reduced infection and every death which occurred was examined by the deputy medical director."