Mortality Figures

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How do we identify our mortality rate? 

We use a variety of data indicators, analysis and methods to carefully and actively monitor our hospital mortality rates. Mortality is closely monitored and discussed every month as part of the Medical Director’s patient safety report which is presented at our public Trust Board meetings. These reports are also available on our website.

There are different ways in which hospital mortality can be measured. For a number of years the Trust has used the CHKS (Comparative Health Knowledge Systems) Risk Adjusted Mortality (RAMI) as its benchmarking model to allow for the monitoring of mortality rates among our patients and the tracking of outcomes with specific clinical conditions. CHKS is an independent provider of healthcare intelligence and quality improvement services.

Adjusted mortality enables the organisation to focus on key indicators, driving down poor performance with other nationally recognised benchmarking tools such as Dr Foster Intelligence’s Hospital Standardised Mortality Ratio (HSMR) and the Summary Hospital Level Mortality Indicator (SHMI).

Hospital Standardised Mortality Ratio (HSMR) 

The Hospital Standardised Mortality Ratio (HSMR) is an indicator of healthcare quality. This is a complex area but helps compare an NHS Trust’s actual number of deaths to its expected or predicted number of deaths. HSMR is a statistical number that enables the comparison of mortality rates between hospitals. This prediction takes account of factors such as the age and sex of patients, their primary diagnosis and complicating factors, and their length of stay in hospital. Standardisation of mortality rates allows comparison between different hospitals, serving different communities.

HSMR is based on the likelihood of a patient dying of the condition with which they were admitted to hospital (i.e. the patient’s recorded primary diagnosis). This means this methodology relies on accurate diagnosis and record-keeping by doctors, and appropriate data coding.

If a Trust has an HSMR of 100, this means that the number of patients who died is exactly as would be expected. Values above 100, suggest a higher than expected mortality and those below as within an acceptable range. HSMR is an important indicator that acts as a smoke alarm for potential problems with the quality of care. It is a trigger for investigation.

The chance of dying from each condition is calculated by looking at all the patients diagnosed with that condition and then all those who died from it, in all hospitals, over the course of a year. A Trust’s HSMR is calculated by applying this methodology to all 56 diagnosis groups in the Dr Foster Intelligence model.

HSMR looks at all deaths that occur prior to discharge from the NHS hospital system – i.e. deaths while under the care of the NHS. The logic here is that the point of discharge is clinically determined – either you are well enough to be discharger or you are dead. The difficulty is that it misses those patient transferred to die in a different environment outside the NHS – at home, in a nursing care home or in a hospice. This distortion has been relatively small in the past but has increased in some instances recently.

Also noting is that Dr Foster Intelligence produces HSMR data in which deaths are attributed to any hospital that treated a patient. If a patient is treated in hospital A and then transferred to hospital B where they die, the death counts as a death for both hospital A’s patient and hospital B’s.

As well as an individual patient’s diagnosis, HSMR is also influenced by a number of other factors including the patient’s age, the method of admission (e.g. elective/planned surgery or emergency), any underlying health problems the patient may have, and the level of social deprivation or health standards for that area in which the patient lives. 

It is hoped that we will begin to see an increase in the Palliative Care coding and this will be routinely monitored in the coming months to monitor progress. 


Mortality across our hospitals has decreased every year since 2005. According to recent figures by any indicator, including Dr Foster and CHKS, we have maintained steady improvement in our risk adjusted hospital mortality rate.

The Trusts rolling Risk Adjusted Mortality (2011 methodology) shows the previous twelve months each month and provides evidence of reduction over the last 12 months avoiding month on month variation.

The Crude Mortality (number of deaths as a percentage of inpatient spells) continues to fall.

The number of deaths as a percentage of inpatient spells across our hospitals continues to decrease. This is encouraging. However, because mortality measures compare a Trust’s mortality performance with other Trusts, unless our crude death rate decreases faster than our peers’, our mortality ratio will statistically increase.

There are three key factors that affect mortality ratios – the accuracy of patient records, diagnosis and coding, and, most importantly, the care we provide to our patients.

During the last year we have established a Trust Mortality Review Group which is chaired by the Medical Director and comprises a number of our senior hospital doctors. A Mortality Action Plan is being implemented to eliminate variation in the delivery of clinical care and improve our doctor’s coding of primary diagnosis. This will ultimately improve patient outcomes across all our hospitals and clinical services.

The Trust is in a transition phase moving from using CHKS - Risk Adjusted Mortality Index (RAMI) to using the HSMR which is referred to in national publications and in the Dr Foster Hospital Guide. A decision to move to HSMR was made because CHKS is essentially limited to comparing our Trust with a ‘peer group’ of other similar Trusts. HSMR allows us to be compared against every Trust in the country.

We recognise we have a great deal of work to do to improve the recording of our patient’s initial diagnosis by our doctors. If that diagnosis is not checked and verified by a senior clinician during admission and if the initial diagnosis is less severe than reality (e.g. an initial diagnosis of pneumonia that should be bronchopneumonia) then this would lead to an incorrect diagnosis which could also result in a much higher HSMR being recorded. 

Real Time Monitoring

We have recently acquired the Dr Foster Intelligence Real Time Monitoring (RTM) Tool to drive our work and to help us identify ways we can improve clinical care and the primary diagnosis coding in relation to mortality.

The RTM is a web-based solution that monitors and identifies potential process, clinical and coding problems around key indicators of clinical quality, including mortality (HSMRs), length of stay, readmission rates and patient safety. This is proving extremely informative and is highlighting different areas for us to focus on.  

We will continue to focus on further improving our hospital mortality rate by improving and standardising the way we code primary diagnosis. We will use the Dr Foster Real Time Monitoring (RTM) tool which will allow us to look more closely at mortality rates by diagnoses and specifically the expected deaths resulting from primary diagnosis. The Trust will continue to review all mortality indicators, driving down poor performance with other nationally recognised benchmarking tools such as the Summary Hospital Level Mortality Indicator (SHMI).

The Trust continues to work with other hospital Trusts as part of the North West Reducing Mortality Collaborative. The collaborative comprises nine NHS Trusts across the region and is supported by AQuA, the Advancing Quality Alliance. The collaborative was set up to improve clinical practice and understanding among clinicians to reduce avoidable deaths. 


The ‘Summary Hospital-level Mortality Indicator (SHMI)’ is another mortality measure and is also published as part of the Dr Foster report.

SHMI looks at factors such as the patient’s age, method of admission and underlying medical conditions. The SHMI is a ratio of the observed deaths over a period of time divided by the expected number given the characteristics of patients treated by that Trust.

The data used to calculate the SHMI includes all deaths in hospital, plus those deaths occurring within 30 days after discharge from hospital. Worth noting is that “after discharge” is a random moment in time and responsibility for deaths that occur between discharge and 30 days later are harder to determine. The SHMI only attributes a death to the hospital which last treated the patient prior to death. SHMI does not adjust for palliative care because of the unreliability of coding. So some hospitals may appear to have a worse SHMI than they should because no allowance has been made for patients admitted for care in the last days of life.

The Trust’s reported SHMI for 2011/12 was 1.05. The latest published data for SHMI (Published April 13) for the period Oct 11 to September 12 is 1.08.

Percentage of admissions with palliative care coding

The SHMI makes no adjustments for palliative care. This is an indicator designed to accompany the SHMI and gives a measure of the palliative care provided by each provider reported in the SHMI.

In a recent review by the Trust, we have since revised and approved a policy which outlines how any patient case note is to be highlighted with the use of a stamp and sticker system to identify that the patient has had some level of Specialist Palliative Care from either the Consultant on-site or the Macmillan Nurse Service. This Policy has been re-published to all staff involved with the emphasis being firmly on the importance of making it very clear and concise within the case note that the patient has received Specialist Palliative Care.

Dr Foster

Since November 2001, Dr Foster Intelligence – a provider of comparative healthcare information - has annually published its Hospital Guide. This national report includes rankings of NHS Acute Trust’s perceived relative performance with respect to patient safety and clinical effectiveness. HSMR is routinely included in its performance indicators.

The Dr Foster Intelligence 11th Hospital Guide was published in December 2012. Using Dr Foster methodology the Trust’s Hospital Standardised Mortality Ratio (HSMR) was recorded as 102 covering the period from April 2011 – March 2012. This was within the expected range. This figure compares with the figure of 100 as reported in last year’s Dr Foster Hospital Guide 2011 and in 2010 the Trust’s HSMR was 110. Our latest published year to date figures for HSMR for the period April 2012 to January 2013 was 103.