One of the most prominent methods of comparing hospital death rates has been the hospital standardised mortality ratio, promulgated by firm Dr Foster and used to create its annual Hospital Guide since 2001.

The next guide is expected to be published at the end of this month.

In advance of this year’s guide Dr Foster has identified two hospital trusts which reported “unusual” levels of patients recorded as having received palliative care.

Recording large proportions of patients as receiving palliative care can reduce a hospital’s HSMR, as palliative patients are effectively excluded when death rates are calculated.

Dr Foster said two trusts -  Basingstoke and North Hampshire Foundation Trust and Medway Foundation Trust - have an “unusual pattern” in their palliative care coding. In 2009-10 both trusts recorded that around 45 per cent of the relevant patient population was receiving palliative care.

The firm’s director of research Roger Taylor said in a statement: “While overall coding is improving, there are areas, such as palliative care coding, where clearer direction is needed.”

Medway medical director Gray Smith-Laing said reasons for its high palliative care rate included high mortality in the area, the design and extent of its palliative care service, and the fact it had an active outreach service.

He said it had been high for several years but there was no significant impact on its HSMR.

He added: “It has not been done in any way to have an effect on the HSMR. From my point of view the vital thing is that our patients get good palliative care.”

He said new coding guidance issued in July was likely to reduce its rate, and said further clearer guidance would be helpful.

Basingstoke and North Hampshire Foundation Trust declined to comment.

Dr Foster Hospital Guide consultation

The new mortality indicator suffers from mixed messages