Indicator Specification:

Transcription

1 Indicator Specification: CCG OIS 1.4 Myocardial infarction, stroke and stage 5 chronic kidney disease in people with diabetes Indicator Reference: I00770 Version: 2.0 Date: March 2015 Author: Clinical Indicators Team 1 Copyright 2015, Health and Social Care Information Centre.

2 Document Management Revision history Version Date Summary of Changes 1.0 March 2014 Initial Release 2.0 March 2015 Revised format and amendment to standardisation methodology. The indicator is now presented as an indirectly standardised ratio. Indicator assurance Status Date Methodology Review Group Recommended Indicator Governance Board Assured Copyright 2015, Health and Social Care Information Centre.

3 Contents Overview 4 Indicator title 4 Indicator family name 4 Condition / Topic area 4 Detailed Descriptor 4 Data Sources 5 Construction 5 Calculation Methodology 5 Calculation 5 Presentation 8 Breakdowns 8 Disclosure control 8 Excel and CSV output 8 Appendices 9 Appendix 1 NDA Data Filters 9 Appendix 2 Complication ICD10 codes 10 3 Copyright 2015, Health and Social Care Information Centre.

4 Overview Indicator title Myocardial infarction, stroke and stage 5 chronic kidney disease in people with diabetes. Indicator family name CCG Outcomes Indicator Set (OIS) Domain 1: Preventing people from dying prematurely. Condition / Topic area Endocrine, nutritional and metabolic. Health and Social Care Information Centre Indicator Portal code I00770 Detailed Descriptor Plain English description CCG OIS 1.4 measures the number of people with diabetes that have myocardial infarction, stroke and stage 5 chronic kidney disease. Technical description Indirectly age and sex standardised ratio of myocardial infarction, stroke and stage 5 chronic kidney disease in people with diabetes. 4 Copyright 2015, Health and Social Care Information Centre.

5 Data Sources Denominator National Diabetes Audit (NDA) Numerator Hospital Episode Statistics (HES) Admitted Patient Care (APC) Standard Population National count of people with diabetes identified by the NDA who were alive at the start of the follow-up period. Construction Calculation Methodology Introduction This indicator calculates the ratio of people with diabetes who develop long term conditions or complications that may be exacerbated by poor management of diabetes. It is considered useful in measuring the quality of commissioning for people with diabetes. Data Fields The data fields supplied by the NDA are as shown below. Details of the NDA are available from Derived_GP_Practice_Code Complication_group_A Age Derived_clean_sex The data fields are extracted as counts at patient level and are aggregated to CCG level to produce the indicator. Data Filter The filters applied to the NDA to produce the indicator are detailed in Appendix 1. Calculation This indicator is calculated as a ratio indirectly standardised by age and sex. 5 Copyright 2015, Health and Social Care Information Centre.

6 Denominator The number of people with diabetes identified by the NDA who were alive at the start of the follow-up period. Numerator The number of people in the denominator who have a HES primary or secondary diagnosis (ICD-10) codes, or primary and secondary OPCS codes during the follow-up period of myocardial infarction, stroke or end stage kidney disease (see Appendix 2 for details of codes). Indirect Standardisation The indirectly age and sex standardised ratio (ISR) is the ratio of events that would occur in a standard population if that population were to experience the age and sex specific rates of the subject population. The ISR is given by: Where: O is the total observed number of events in the local or subject population E is the total number of expected events in the local or subject population, given the standard rates λ i in the reference or standard population; O i is the observed numbers of events in the local or subject population in age and sex group i; E i is the expected number of events in the local or subject population in age and sex group i, given the standard rate λ i in the reference or standard population; n i is the number of individuals in the local or subject population in age and sex group i; λ i is the crude age-specific rate in the reference or standard population in age and sex group i; The following age bands are used: 0-4, 5-9, 10-14, 15-19, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, 75-79, 80-84, 85+. Due to the follow up period for complications being one year, the 0-4 age band will only include those aged 1-4 for the complication groupings. Confidence Intervals Confidence intervals will be calculated as specified in Commonly used public health statistics and their confidence intervals (APHO, March 2008). The 100(1 α)% confidence limits for the ISR are given by: 6 Copyright 2015, Health and Social Care Information Centre.

7 Where O lower and O upper are the lower and upper confidence limits for the observed number of events; Using Byar s 1 method, the 100(1 α)% confidence limits for the observed number of events are given by: Where z is the 100(1 α/2)th percentile value from the Standard Normal distribution. For example, for a 95% confidence interval, α = 0.05 and z = 1.96 (i.e. the 97.5th percentile value from the Standard Normal distribution). For smaller numerators of less than 389, Byar's method can be less accurate and an exact method based on the Poisson distribution can be used. For 95% confidence intervals, Byar's method is extremely accurate for numerators of 5 or more, but for 99.8% confidence intervals it is less accurate. Using the link between the Poisson and distributions 2, the equations for O lower and O upper above can be replaced by: where: 2 lower is the 100(1 α/2)th percentile value from the 2 distribution with 2O degrees of freedom; 2 upper is the 100(α/2)th percentile value from the 2 distribution with 2O+2 degrees of freedom. 1 Breslow NE, Day NE. Statistical methods in cancer research, volume II: The design and analysis of cohort studies. Lyon: International Agency for Research on Cancer, World Health Organisation; Armitage P, Berry G. Statistical methods in medical research (3rd edn). Oxford: Blackwell; Copyright 2015, Health and Social Care Information Centre.

8 Presentation Breakdowns Time periods Financial year 2011/12 onwards. Demographic None. Geographic England CCG Disclosure control When publishing the data, if the indicator is calculated from a numerator of 1 to 5, the value is suppressed to ensure an individual s identity is not at risk of being disclosed. If there is only one value suppressed in this way, the ratio based upon the next lowest numerator is also suppressed; this reduces the risk of the first suppressed number being identifiable in isolation. Ratios are rounded to one decimal place before publication. Excel and CSV output Column name Reporting Period Breakdown Level Level Description ISR CI Lower CI Upper Denominator Numerator Output Financial year England, CCG CCG Code CCG Name Indirectly standardised ratio ISR lower 95% confidence interval ISR upper 95% confidence interval The indicator denominator figure The indicator numerator figure 8 Copyright 2015, Health and Social Care Information Centre.

9 Appendices Appendix 1 NDA Data Filters Data Fields 1. Field Name: Age Conditions: Calculated from the NDA and is the age of the patient at the start of the follow-up period. Rationale: Age at time of having the complication. 2. Field Name: Derived_clean_sex Rationale: Sex of patients in the NDA 3. Field Name: Derived_GP_Practice_Code Rationale: GP Practice Code for patients in the NDA 4. Field Name: Complication Conditions: Patients in the NDA who were alive at the start of the follow-up period, were matched to Hospital Episode Statistics (HES), a record of every hospital admission in England. Patients were identified as having a complication if they had a primary or secondary diagnosis (ICD10) code from the list in Appendix 2, or a primary or secondary operation (OPCS) code from the list in Appendix 2 in HES during the 12 month follow-up period. For example, patients included in the NDA and still alive on the 31 st March 2010 were matched with HES data from 1 st April 2010 to 31 st March 2011 to identify which of them had had an admission for a complication of MI, Stroke or RRT. Rationale: This identifies which patients have had a relevant complication during the follow up period. 9 Copyright 2015, Health and Social Care Information Centre.

10 Appendix 2 Complication ICD10 codes The ICD10 (diagnosis) / OPCS4 (procedure) codes used by the NDA are: ICD10 codes for Myocardial infarction (MI) I21.0 Acute transmural myocardial infarction of anterior wall I21.1 Acute transmural myocardial infarction of inferior wall I21.2 Acute transmural myocardial infarction of other sites I21.3 Acute transmural myocardial infarction of unspecified site I21.4 Acute subendocardial myocardial infarction I21.9 Acute myocardial infarction, unspecified I22.0 Subsequent myocardial infarction of anterior wall I22.1 Subsequent myocardial infarction of inferior wall I22.8 Subsequent myocardial infarction of other sites I22.9 Subsequent myocardial infarction of unspecified site ICD10 codes for Stroke I61.0 Intracerebral haemorrhage in hemisphere, subcortical I61.1 Intracerebral haemorrhage in hemisphere, cortical I61.2 Intracerebral haemorrhage in hemisphere, unspecified I61.3 Intracerebral haemorrhage in brain stem I61.4 Intracerebral haemorrhage in cerebellum I61.5 Intracerebral haemorrhage, intraventricular I61.6 Intracerebral haemorrhage, multiple localized I61.8 Other intracerebral haemorrhage I61.9 Intracerebral haemorrhage, unspecified I63.0 Cerebral infarct due to thrombosis of precerebral arteries I63.1 Cerebral infarction due to embolism of precerebral arteries I63.2 Cereb infarct due unsp occlusion or stenos precerebrl arts I63.3 Cerebral infarction due to thrombosis of cerebral arteries I63.4 Cerebral infarction due to embolism of cerebral arteries I63.5 Cerebrl infarct due unspec occlusion or stenos cerebrl arts I63.6 Cereb infarct due cerebral venous thrombosis, nonpyogenic I63.8 Other cerebral infarction I63.9 Cerebral infarction, unspecified 10 Copyright 2015, Health and Social Care Information Centre.

11 I64.X Stroke, not specified as haemorrhage or infarction I67.9 Cerebrovascular disease, unspecified ICD10 codes for Renal Replacement Therapy (RRT) N18.0 End-stage renal disease Z49.0 Preparatory care for dialysis Z49.1 Extracorporeal dialysis Z49.2 Other dialysis Z99.2 Dependence on renal dialysis OPCS codes for RRT M01.1 Autotransplantation of kidney M01.2 Allotransplantation of kidney from live donor M01.3 Allotransplantation of kidney from cadaver NEC M01.4 Allotransplantation of kidney from cadaver heart-beating M01.5 Allotransplantation of kidney from cadaver non-heart-beating M01.8 Transplantation of kidney, Other specified M01.9 Unspecified transplantation of kidney X40.1 Renal dialysis X40.2 Peritoneal dialysis NEC X40.3 Haemodialysis NEC X40.4 Haemofiltration X40.5 Automated peritoneal dialysis X40.6 Continuous ambulatory peritoneal dialysis X40.7 Haemoperfusion X40.8 Other specified compensation for renal failure X40.9 Unspecified compensation for renal failure 11 Copyright 2015, Health and Social Care Information Centre.