What does it show?
Mortality results and funnel plot for all CCGs and LHBs based on a year’s data, plus information about how mortality results are derived.
The national audit for stroke (SSNAP) has been collecting data on stroke admissions since the beginning of 2013. We are now reporting mortality rates by CCGs/LHBs for the year April 2016 to March 2017. We are required to put these data into the public domain.
We have adjusted for case mix including stroke severity. The model used for this has been published in Stroke, and the published paper shows that the model is very reliable when externally validated. Briefly, the model takes account of the age of the patient, whether they are in atrial fibrillation (AF) before stroke, stroke type (haemorrhage or infarction), and the NIHSS score at arrival (where this is not available, the level of consciousness at arrival).
How can you use it?
Following analysis and case mix adjustment the expected number of deaths for each CCG/LHB's patients, and the Standardised Mortality Ratio was calculated. Each CCG/LHB’s SMR and the control limits are plotted on the funnel plot.
The funnel plot is useful for identifying outliers, taking into account the number of patients per CCG/LHB. What is therefore important is whether the point representing each CCG/LHB lies outside the dotted lines (the funnel). Points inside the funnel represent CCGs/LHBs where the number of observed deaths is not significantly different to the number of expected deaths.
You can find out more about outlier policy for SSNAP stroke mortality reporting here
The funnel area of the plot becomes narrower as the number of expected deaths increases because the more patients there are, the less likely variations in the number of deaths are due to chance alone.
For those CCGs/LHBs where the number of observed deaths is significantly higher than the number of expected deaths, their point on the funnel plot lies above the top dotted line. These CCGs/LHBs are outliers at the 99.8% control limit and their SMR in the public table is higher than their upper 99.8% control limit.
For more detailed information for SSNAP users on mortality reporting please see our mortality information sheet here.
Where can I find it?
CCG and LHB Public table of mortality is available here - Results > Clinical audit > National and then click on ‘Annual’ radio button.
We would greatly appreciate any feedback that you have on this report. If you found the report useful, or think there is any way that we could improve the report, we would love to hear from you. Please feel free to email via the contact button, or leave a comment below.