WYE Valley NHS Trust has challenged statistics that show its death rates as amongst the highest in England.

Trust medical director Peter Wilson said this morning that the “highly derived and complicated” statistics need to be seen in context.

The Trust is one of six with death rates identified as "higher than expected" by the Health and Social Care Information Centre (HSCIC) which analysed mortality ratios between 2011-2013 Dr Wilson said the resulting HSCIC report showed that in each of the quarters in the past year - April, July and October 2013 - the Trust’s mortality rates had been “as expected”.

“These figures are highly derived and complicated statistics. They are indicators only and not absolute measurements of the quality of services we offer,” said Dr Wilson.

“Care must be taken not to view this figure in isolation. It needs careful interpretation and needs to be viewed alongside other evidence as part of a set of indicators of quality of care, which, when viewed in context, paint a detailed picture of a hospital’s overall performance,” he said.

An independent report published by NHS watchdog Dr Foster in November showed the Trust as continuing to meet the acute hospital performance indicator HSMR (Hospital Standardised Mortality Ratio) expectations, which is a different mortality measure to that used by HSCIC.

The picture in Herefordshire is complicated by the fact that Wye Valley NHS Trust is an integrated care organisation which provides both Acute Hospital and Community Health services for the county - many trusts solely provide Acute Hospital services.

This means that the HSCIC statistics for the Trust included deaths occurring outside of the hospital, but within 30 days of discharge. In the Trust’s case around 25 per cent of these recorded deaths occurred outside of the hospital.

However, the figure does not make any adjustment for deaths of patients with a terminal illness who die at home, in a hospice or in hospital.

Statistics for the past 10 years show the Trust’s crude mortality rate has been falling. More recent data contained in the full HSCIC report shows that the Trust’s SHMI indicators published in April, July and October 2013, were "as expected".

“As a Trust, we have been committed to better understanding of our mortality indicators and we continue to regularly review the performance of all areas of our operation and carry out detailed reviews where performance falls below the high standards we expect,” said Dr Wilson.

Out yesterday (Wed) the HSCIC report compared the actual number of patients to die following hospitalisation at a particular trust and the number that would be expected to die. In turn, that expectation figure is based on an average for England average and the characteristics of the patients treated at a particular trust.

The study takes in deaths occurring during a stay at a trust and within 30 days of discharge, with the eventual vales for individual trusts categorised "as expected", "lower than expected" or "higher than expected".

In presenting its report, the HSCIC stressed that mortality figures require careful interpretation and need to be viewed alongside other evidence, rather than as a stand-alone verdict on trust performance.

The trusts categorised as higher than expected between July 2011 and June 2013 were: Mid Cheshire Hospitals NHS Foundation Trust, Colchester Hospital University NHS Foundation Trust, Aintree University Hospital NHS Foundation Trust, Wye Valley NHS Trust, Blackpool Teaching Hospitals NHS Foundation Trust and East Lancashire Hospitals NHS Trust.

There are currently a number of mortality indicators used in the NHS designed by different organisations using different statistical methods to help identify trends that require further investigation.