The Intelligent Board 2009 - commissioning to reduce inequalities
SAR methodology
Analysis of standardised admission ratios can be used to understand and pinpoint localised 'at risk' communities. The following outlines the methodology:
Stroke standardised admission ratio
- Metric
- Standardised admission ratio
- Methodology
-
The ratio of the observed number of admissions for Stroke to the expected number.
The ratio is expressed as an index where the expected value equals 100. Hence values greater than 100 suggest a higher than expected number of admissions, while values less than 100 suggest fewer admissions than expected.
Expected values are calculated using national rates. The model calculates a probability or risk of admittance for every combination of adjusted factors. The expected value is the sum of all the (probabilities multiplied by the population).
SAR values should always be interpreted along with their confidence limits.
- Adjustments
-
Expected values are calculated from national admissions and population data. Expected values are adjusted by:
- Diagnosis, Procedure, HRG or Outpatient Specialty
- Financial year
- Age (5-year bands for residential, 10 year bands for registered)
- Sex
- Deprivation* (Output Area for residential, GP Practice code for registered)
- Admission or Appointment type
- Confidence limits
-
You can be 95% confident that the true SAR lies between these confidence limits. They are calculated using Byar's approximation:-
Lower 95% limit
(observed /expected ) * 100 * ((1- (1/(9 * observed )) - (1.96 / (3* sqrt(observed )))) ^ 3Upper 95% limit
((observed +1)/expected ) * 100 * ((1- (1/(9*(observed +1))) + (1.96/(3* sqrt((observed +1)))))^3If the lower limit is greater than 100, there's a 97.5% chance that performance is worse than expected. If the upper limit is less than 100 , there's a 97.5% chance that performance is better than expected.
- Admission type
- Non-elective admissions
- Data Source
- SUS - CDS
- Time frame
- September 2007 - August 2008
- Basis
- Registered Primary Care Trust
Ambulatory Care Sensitive conditions (ACS)
- Metric
-
Standardised admission ratio for all ambulatory care sensitive conditions 5 year trend.
ACS Conditions are long-term health conditions that can often be managed with timely and effective treatment in the community without hospitalisation.
ICD-10 codes: see Appendix
- Methodology
-
The ratio of the observed number of (ACS) admissions to the expected number.
The ratio is expressed as an index where the expected value equals 100. Hence values greater than 100 suggest a higher than expected number of admissions, while values less than 100 suggest fewer admissions than expected.
Expected values are calculated using national rates. The model calculates a probability or risk of admittance for every combination of adjusted factors. The expected value is the sum of all the (probabilities multiplied by the population).
SAR values should always be interpreted along with their confidence limits.
- Adjustments
-
Expected values are calculated from national admissions and population data. Expected values are adjusted by:
- Diagnosis, Procedure, HRG or Outpatient Specialty
- Financial year
- Age (5-year bands for residential, 10 year bands for registered)
- Sex
- Deprivation* (Output Area for residential, GP Practice code for registered)
- Admission or Appointment type
- Confidence limits
-
You can be 95% confident that the true SAR lies between these confidence limits. They are calculated using Byar's approximation:-
Lower 95% limit
(observed /expected ) * 100 * ((1- (1/(9 * observed )) - (1.96 / (3* sqrt(observed )))) ^ 3Upper 95% limit
((observed +1)/expected ) * 100 * ((1- (1/(9*(observed +1))) + (1.96/(3* sqrt((observed +1)))))^3If the lower limit is greater than 100, there's a 97.5% chance that performance is worse than expected. If the upper limit is less than 100 , there's a 97.5% chance that performance is better than expected.
- Admission type
- All admissions
- Data Source
- SUS - CDS
- Time frame
- April 2003 - March 2008
- Basis
- Registered Primary Care Trust
- Appendix
-
Condition ICD10 codes Influenza and pneumonia J10,J11,J13,J14,J153,J154,J157,J159,J168,J181,J188 Other vaccine preventable A35-A37,A80,B05,B06,B161,B169,B180,B181,B26,G000,M014 Asthma J45,J46 Congestive heart failure I110,I50,J81 Diabetes complications E100-E108,E110-E118,E120-E128,E130-E138,E140-E148 Chronic obstructive pulmonary disease J20,J41-J44,J47 Angina I20,I240,I248,I249 Iron deficiency anaemia D501,D508,D509 Hypertension I10,I119 Nutritional deficiencies E40-E43,E55,E643 Dehydration and gastroenteritis E86,K522,K528,K529 Pyelonephritis N10-N12,N136 Perforated/bleeding ulcer K250-K252,K254-K256,K260-K262,K264-K266,K270-K272,K274-K276,K280-K282,K284-K286 Cellulitis L03,L04,L080,L088,L089,L980 Pelvic inflammatory disease N70,N73,N74 Ear, nose and throat infections H66,H67,J02,J03,J06,J312 Dental conditions A690,K02-K06,K08,K098,K099,K12,K13 Convulsions and epilepsy G40,G41,015,R56 Gangrene R02
Alcohol related conditions
- Metric
-
Standardised admission ratio for alcohol related liver disease and mental disorders combined.
ICD-10 codes: Liver disease, alcohol related- K70, Alcohol related mental disorders- F10,G312,R780
- Methodology
-
The ratio of the observed number of admissions for alcohol related conditions to the expected number.
The ratio is expressed as an index where the expected value equals 100. Hence values greater than 100 suggest a higher than expected number of admissions, while values less than 100 suggest fewer admissions than expected.
Expected values are calculated using national rates. The model calculates a probability or risk of admittance for every combination of adjusted factors. The expected value is the sum of all the (probabilities multiplied by the population).
SAR values should always be interpreted along with their confidence limits.
- Adjustments
-
Expected values are calculated from national admissions and population data. Expected values are adjusted by:
- Diagnosis, Procedure, HRG or Outpatient Specialty
- Financial year
- Age (5-year bands for residential, 10 year bands for registered)
- Sex
- Deprivation* (Output Area for residential, GP Practice code for registered)
- Admission or Appointment type
- Confidence limits
-
You can be 95% confident that the true SAR lies between these confidence limits. They are calculated using Byar's approximation:-
Lower 95% limit
(observed /expected ) * 100 * ((1- (1/(9 * observed )) - (1.96 / (3* sqrt(observed )))) ^ 3Upper 95% limit
((observed +1)/expected ) * 100 * ((1- (1/(9*(observed +1))) + (1.96/(3* sqrt((observed +1)))))^3If the lower limit is greater than 100, there's a 97.5% chance that performance is worse than expected. If the upper limit is less than 100, there's a 97.5% chance that performance is better than expected.
- Admission type
- All admissions
- Data Source
- SUS - CDS
- Time frame
- September 2007 - August 2008
- Basis
- Registered Primary Care Trust
Coronary atherosclerosis standardised admission ratio
- Metric
- Standardised admission ratio
- Methodology
-
The ratio of the observed number of admissions for Coronary atherosclerosis to the expected number.
The ratio is expressed as an index where the expected value equals 100. Hence values greater than 100 suggest a higher than expected number of admissions, while values less than 100 suggest fewer admissions than expected.
Expected values are calculated using national rates. The model calculates a probability or risk of admittance for every combination of adjusted factors. The expected value is the sum of all the (probabilities multiplied by the population).
SAR values should always be interpreted along with their confidence limits.
- Adjustments
-
Expected values are calculated from national admissions and population data. Expected values are adjusted by:
- Diagnosis, Procedure, HRG or Outpatient Specialty
- Financial year
- Age (5-year bands for residential, 10 year bands for registered)
- Sex
- Deprivation* (Output Area for residential, GP Practice code for registered)
- Admission or Appointment type
- Confidence limits
-
You can be 95% confident that the true SAR lies between these confidence limits. They are calculated using Byar's approximation:-
Lower 95% limit
(observed /expected ) * 100 * ((1- (1/(9 * observed )) - (1.96 / (3* sqrt(observed )))) ^ 3Upper 95% limit
((observed +1)/expected ) * 100 * ((1- (1/(9*(observed +1))) + (1.96/(3* sqrt((observed +1)))))^3If the lower limit is greater than 100, there's a 97.5% chance that performance is worse than expected. If the upper limit is less than 100, there's a 97.5% chance that performance is better than expected.
- Admission type
- All admissions
- Data Source
- SUS - CDS
- Time frame
- September 2007 - August 2008
- Basis
- Registered Primary Care Trust
Diabetes with complications (ACS)
- Metric
-
Standardised admission ratio for the ambulatory care sensitive condition of Diabetes with complications.
ACS Conditions are long-term health conditions that can often be managed with timely and effective treatment in the community without hospitalization.
ICD-10 codes: E100-E108,E110-E118,E120-E128,E130-E138,E140-E148
- Methodology
-
The ratio of the observed number of admissions for Diabetes to the expected number.
The ratio is expressed as an index where the expected value equals 100. Hence values greater than 100 suggest a higher than expected number of admissions, while values less than 100 suggest fewer admissions than expected.
Expected values are calculated using national rates. The model calculates a probability or risk of admittance for every combination of adjusted factors. The expected value is the sum of all the (probabilities multiplied by the population).
SAR values should always be interpreted along with their confidence limits.
- Adjustments
-
Expected values are calculated from national admissions and population data. Expected values are adjusted by:
- Diagnosis, Procedure, HRG or Outpatient Specialty
- Financial year
- Age (5-year bands for residential, 10 year bands for registered)
- Sex
- Deprivation* (Output Area for residential, GP Practice code for registered)
- Admission or Appointment type
- Confidence limits
-
You can be 95% confident that the true SAR lies between these confidence limits. They are calculated using Byar's approximation:-
Lower 95% limit
(observed /expected ) * 100 * ((1- (1/(9 * observed )) - (1.96 / (3* sqrt(observed )))) ^ 3Upper 95% limit
((observed +1)/expected ) * 100 * ((1- (1/(9*(observed +1))) + (1.96/(3* sqrt((observed +1)))))^3If the lower limit is greater than 100, there's a 97.5% chance that performance is worse than expected. If the upper limit is less than 100, there's a 97.5% chance that performance is better than expected.
- Admission type
- Non-elective admissions
- Data Source
- SUS - CDS
- Time frame
- September 2007 - August 2008
- Basis
- Registered Primary Care Trust