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Ambulatory Sensitive (avoidable) Hospitalisations

Basic Facts

Stage of development

Implemented

Potential or current usage

The rate of ambulatory-sensitive hospital admissions is often used as a measure of the effectiveness of the interface between primary and secondary health care. The assumption is that better management of chronic conditions such as diabetes and cardiovascular disease within local communities has the potential to reduce the number of avoidable hospital admissions (and to moderate demand on hospital resources) Diagnosis information on hospitalisations sent to the national dataset is analysed quarterly to provide avoidable ambulatory sensitive hospitalisations.

Brief overview of the measure

General description

Ambulatory sensitive hospital admissions (ASH) are those admissions (mostly acute) that are considered by expert opinion to be potentially avoidable through interventions in out-of-hospital settings. They are an outcome indicator used to evaluate access to primary health care (eg, GP visits).

Rationale for selection

Ambulatory-sensitive hospitalisations were included as a National Health Target from July 2007. They provide an indication of access to, and the effectiveness of, primary health care, as well as management of the interface between the primary and secondary health sectors. If there is good access to effective primary health care for all population groups, then it is reasonable to expect that there will be lower levels of ambulatory sensitive hospital admissions. This indicator can also highlight disparities between different population groups that will assist with DHB planning to reduce disparities.

Type of measure

Outcomes

Domain(s) of quality

Effectiveness, Equity and access

Application and interpretation of the measure

Stated intent of the measure

The indicator seeks to achieve a reduction in the total number of ambulatory sensitive admissions and in the variation in ASH rates between DHBs and between different population groups.

Caveats - Considerations

There has been much debate within New Zealand and beyond about the usefulness or otherwise of ambulatory sensitive admissions as a measure of access to services and effectiveness of system performance. There is evidence of their validity as proxy indicators of access , but this remains a contested and controversial indicator. From a practical perspective, measuring change over time requires consistency in definition of both the basket of conditions and exclusions from the underlying data. Periodically there have been changes to the definition of this indicator. As such, it is important to ensure comparability of data presented according to the same definition.

Level of health care delivery/setting

Specifies the level of health care delivery/setting to which the measure most appropriately applies. (Use of the measure at other levels of health care delivery may be possible, although it is important to note that in these instances some variables for the measure may be subject to change.)

Target population

This indicator is inclusive of all age ranges, ethnicities and genders.

Stratification by vulnerable populations

This indicator is best understood when stratified by ethnicity and socio economic status. Stratifying by age may also be of interest.

Possible sources of bias or confounding

Includes practitioner, organisational and patient factors e.g. demography, case mix, compliance that need to be allowed for when interpreting results.

Calculation of the measure

Output of calculation

Hospitalisations of people less than 75 years old resulting from diseases sensitive to prophylactic or therapeutic interventions that are deliverable in a primary health care setting. The output of the quarterly analysis of the national dataset is presented as an example. See attached file.

Numerator description

Hospitalisations of people less than 75 years old resulting from diseases sensitive to prophylactic or therapeutic interventions that are deliverable in a primary health care setting. The output of the quarterly analysis of the national dataset is presented as an example below.


Numerator exclusions

Casemix and Hospital Throughput filters are applied. Filters/ exclusions: • Exclude Neonates Age < 29 days for ASH • Excludes people 75+ due to comorbidities • Acute/Arranged Admission Types only except for Dental where Electives are to be included • Same day ED cases meeting the 3 hour rule • Primary Rural Facilities • = Adult Only (age 15+) • ** = All ages • WIES09 filter • NZDep06 The appendix in the Hospital Throughput Report provides further detail. http://www.health.govt.nz/publication/ministry-healths-hospital-throughput-2003-2004-report)

Denominator description

Expected admissions derived from indirect standardisation of NZ population rates for the relevant conditions.

Denominator exclusions

Casemix and Hospital Throughput filters are applied. The appendix in the Hospital Throughput Report provides further detail. http://www.health.govt.nz/publication/ministry-healths-hospital-throughput-2003-2004-report)

Time period

Quarterly reporting of this indicator is appropriate.

Data source

NMDS

Method of extraction

Filtering of Hospital Discharge Data

Note: in the main body of this document, comments such as “refer XXX” indicate that the complete list of values are in Appendix One under “XXX”.

1. Non-treated patients

Events where no treatment is provided are excluded. These include boarders who may be admitted or cancelled operations.

Boarders are tested for by checking the primary diagnosis code (only) is in the range: ICD10: (Z763, Z764).

Cancelled operations are tested for by checking that:

  • the primary operation/procedure code is blank and
  • the event is non-acute (i.e., admission type not ‘AC’) and
  • length of stay is less than two days and
  • one (or more) of the first six diagnosis codes contain the following codes:
– ICD10: (Z530, Z531, Z532, Z538, Z539).

2. Error DRGs

Events coded to an Error AR-DRG are excluded. Error AR-DRGs are in the range: · AR-DRG Version 5.0: (960Z, 961Z, 963Z).

3. Renal Dialysis

Renal Dialysis AR-DRGs are excluded. Renal Dialysis AR-DRGs are in the range:

  • AR-DRG Version 5.0: (L61Z, L61Y).

4. Same day chemotherapy and radiotherapy

Some day cases for chemotherapy and radiotherapy are excluded from case-mix purchasing.

These events are tested for by checking:

  • that the admission date is the same as the discharge date and
  • that either of the first two diagnosis codes falls in the range:
– ICD10: (Z511, Z512).

5. Sleep apnoea

  • that the integer difference in days between the discharge and admission dates is less than two and
  • that the AR-DRG is in the range:
– AR-DRG Version 5.0: E63Z.

6. Lithotripsy

Some same day lithotripsy events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • that the primary procedure code falls in the following range:
– ICD10: (3654600, 9095600, 9095700, 9219900) and
  • that the second procedure code falls in the following range:
– ICD10: (3654600, 9095600, 9095700, 9219900, blank) or anaesthetic (refer B1910lk) and
  • that the third procedure code is blank or anaesthetic (refer B1910lk).

7. Colposcopies

Some same day colposcopy events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’)
  • that the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
– ICD10: colposcopy (refer COLPOa) and
  • that the second procedure code falls in the following range:
– ICD10: colposcopy or anaesthetic or blank (refer COLPOa or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

8. Cystoscopies

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’, ‘ZC’) and
  • that the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
– ICD10: cystoscopy (refer cystosa) and
  • that the second procedure code falls in the following range:
– ICD10: cystoscopy or anaesthetic or blank (refer cystosa or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

9. ERCPs

Some same day ERCP (endoscopic retrograde cholangiopancreatography) events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the Admission and Discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
– ICD10: ERCP (refer ERCPa) and
  • that the second procedure code falls in the following range:
– ICD10: ERCP or anaesthetic or blank (refer ERCPa or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

10. Colonoscopies

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
  • that the primary procedure code falls in the following range:
– ICD10: colonoscopy (refer COLONsa) and
  • that the second procedure code falls in the following range:
– ICD10: colonoscopy or anaesthetic or blank (refer COLONsa or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

11. Gastroscopies

Some same day gastroscopies events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
– ICD10: gastroscopy (refer GASTRa) and
  • that the second procedure code falls in the following range:
– ICD10: gastro procedures or anaesthetics (refer BlkGast or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

12. Bronchoscopies

Some same day bronchoscopies events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • the patient’s age is greater than 15 years old and
  • that the primary procedure code falls in the following range:
– ICD10: broncoscopy (refer BRON) and
  • that the second procedure code falls in the following range:
– ICD10: broncoscopy or anaesthetics (refer BRON or B1910lk) and
  • that the third procedure code is anaesthetic or blank (refer B1910lk).

13. Day case blood transfusions

Some same day blood transfusion events are excluded from case-mix purchasing. These events are tested for by checking:

  • that the admission and discharge dates are the same and
  • that the event is non-acute (i.e., admission type not in ‘AC’) and
  • that the primary diagnosis OR the first three procedure codes fall in the range:
– ICD10: primary diagnosis in the range (Z513) OR {primary procedure in the range (9206000,

1370601, 1370602, 1370603) AND

  • second procedure in the range (9206000, 1370601,

1370602, 1370603, blank) AND

  • third procedure blank}.

14. Inconsistent stays

This step identifies pairs of records where the dates of hospitalisation conflict. This is probably due to simple coding errors or errors in updating records. However, it is difficult to determine what are the correct data, so the second (later) hospital event is deleted.

15. Mental health cases

Mental health events are excluded if they have either:

  • a mental health service specialty code, i.e., first character is ‘Y’, or
  • a mental health AR-DRG and there was no operating room procedure performed.

Mental health AR-DRGs are in the range: AR-DRG Version 5.0: U40Z–U68Z.

16. DSS cases (includes AT&R)

DSS events are excluded if they have either:

  • a DSS specialty code, i.e., first character is ‘D’, or
  • a rehab AR-DRG, or
  • a respite care case with no operating room procedure, or
  • discharged from a DSS institution (and does not involve a delivery), and
  • there was no operating room procedure performed)

DSS institutions are (‘3217’, ‘3220’, ‘3232’, ‘3235’, ‘3237’, ‘3238’, ‘3614’, ‘3912’, ‘3913’,’4015’, ‘4017’, ‘4024’, ‘4031’, ‘4222’, ‘5750’, ‘5814’, ‘5229’, ‘5330’, ‘5332’, ‘3226’, ‘3228’, ‘4314’, ‘5914’) and health specialty not in (‘P60’,’P61’, ‘P70’, ‘P71’).

Rehab AR-DRGs are in the range: AR-DRG Version 5.0: Z60A-Z60C.

Respite care primary diagnosis codes are in the range: ICD10: (Z742, Z755).

17. Transfers

When a patient with a condition that requires specialist treatment arrives at a small hospital they will usually be transferred to a larger hospital for that treatment. They will often be transferred back to the original hospital for a period of their after care. If, on the other hand, they arrive at the specialist hospital and live in the vicinity they will spend the whole period of hospitalisation in the one hospital. Thus for the same condition and treatment it is possible to have one or more records. For a consistent dataset, transferred records have been joined back together. Transferred records are joined if a discharge record shows a person admitted to the same or another hospital within the same DHB, on the same or following day, with a discharge type (from the previous hospital event) indicating a transfer. The diagnostic information is retained from the record containing the most expensive AR-DRG and the resultant record is attributed to that hospital. Previous work shows that this procedure is conservative for detecting transfers – as the discharge type is not always scrupulously filled in and routine discharge may be entered in some cases of transfer.

18. Overseas patients

To allow investigation at a DHB region level only, that is, excluding overseas cases, all cases with a domicile code of ‘9999’ have been excluded from this report.

19. Non Medical Surgical

A global exclusion of all DSS or Mental Health or primary maternity cases. DSS and Mental Health defined by health specialty code beginning with ‘D’ or ‘Y’ respectively. Primary maternity cases being cases with a health specialty code beginning with ‘P’ (except for P50) other than neonates discharged from facilities other than designated maternity facilities (refer matfac).

[Neonates are defined using the following code: if substr(hlthspec,1,1)='P' and put(facility,$matfac.) = 'Y' and ((hlthspec in ('P41','P42','P43')) or (nzdrg50 in ('P02Z','P03Z','P04Z','P05Z','P06A','P06B', 'P61Z','P62Z','P63Z','P64Z', 'P65A','P65B','P65C','P65D', 'P66A','P66B','P66C','P67A','P67B')) or (nzdrg50 in ('P01Z','P60A','P60B','P66D','P67C','P67D') and (diag03 ne ' ' or op01 ne ' ') )) then NEONATE='Y';]

20. Designated Agency

A global exclusion of all contracting organisations (agencies) other than those publicly owned agencies (refer desage).

21. Transplants

High cost transplant procedures are excluded as there are wider considerations around the organ location and transport programmes and the ongoing programmes of care for the recipients. These transplants are identified by:

AR-DRGs are in the range: AR-DRG Version 5.0: refer transp.

22. Spinal

Spinal injury care is excluded. These are identified by the health specialty codes S50 and S53.

23. Terminations of Pregnancy

Terminations of pregnancy are excluded. These are identified by:

  • AR-DRG Version 5.0 of O05Z and
  • Admission type not ‘AC’ and
  • Primary procedure in ('3564000','3564300','3564301','3564302') and
  • Primary diagnosis commencing with ‘O04’

24. Non Base Funded

A global exclusion of cases funded other than under public contracts with a specific exclusion of ACC contracted elective admissions.

Public purchasers are identified by the purchaser codes of ('01', '02', '03', '04', '13', '20', '34', '35') and ACC electives are identified by admission type of ‘ZW’.

25. Amniocentesis

Amniocentesis cases are excluded. These are identified by:

  • Admission and discharge dates are the same and
  • Primary procedure code in ('1660000', '1661800', '1662100') and
  • health specialty code beginning with ‘P’ (except for P50)
  • not a neonates (see definition above) and
  • discharged from designated maternity facilities (refer matfac).

26. Chorio Villis Sampling

Chorio Villis Sampling are excluded and are identified by:

  • Admission and discharge dates are the same and
  • Primary procedure code in (‘1660300’) and
  • health specialty code beginning with ‘P’ (except for P50)
  • not a neonates (see definition above) and
  • discharged from designated maternity facilities (refer matfac).

27. Rhesus Isoimmunisation

Rhesus Isoimmunisation are excluded and are identified by:

  • Admission and discharge dates are the same and
  • Primary diagnosis code commencing with (‘O360', 'O361') and
  • health specialty code beginning with ‘P’ (except for P50)
  • not a neonates (see definition above) and
  • discharged from designated maternity facilities (refer matfac).

28. Breastfeeding / Lactation

Breastfeeding / Lactation are excluded and are identified by:

  • Admission and discharge dates are the same and
  • Primary diagnosis code in ('O9230', ‘O9231', ‘O9240', ‘O9241', 'O9250', 'O9251', 'O9260', 'O9261', 'O9270', 'O9271') and
  • health specialty code beginning with ‘P’ (except for P50)
  • not a neonates (see definition above) and

discharged from designated maternity facilities (refer matfac).

Key issues and challenges for data management

Measuring change over time requires consistency in definition of both the basket of conditions and the exclusions from the underlying data. Periodically there are changes in both definitions (eg inclusion of some electives and an additional gastroenteritis code in the basket of conditions and a forthcoming change to include short stay ED admissions in the underlying data). Presentation of the data should be of a trend over a period in time using consistent definitions noting that any report may include results that differ from previous reports.

Appraisal of the measure

Availability of evidence to support application of the measure

Measure is formulated on and underpinned by an evidence based clinical practice guideline., Measure is formulated on and underpinned by evidence from a published systematic review, meta-analysis, or other peer-reviewed synthesis of clinical evidence relating to the area of focus., The measure has been cited in one or more peer-reviewed journals, applying or evaluating the properties of the measure., A formal consensus procedure involving experts in relevant clinical and/or methodological sciences has been completed and documented., The measure has been developed or endorsed by an organization that promotes rigorous development and use of clinical performance measures (at an international, national, regional or local level)., The measure has been developed or endorsed by an organisation seeking to improve clinical effectiveness as part of a continuous quality improvement cycle (at an international, national, regional or local level).

Evidence of feasibility and reliability of implementation

Reliability - The measure has been demonstrated to be reliable (i.e. free from random error)., Interpretation - The measure allows unambiguous interpretation of better or worse performance., Data extraction - Data collection specifications for the measure are well defined., Data sources - Required data elements for the measure can be obtained from existing data sources., Availability of data - Required data elements for the measure can be gathered during routine practice activities, IT software - Existing IT software is sufficient for data collection., Adaptability - Measure is able to be adapted for use in multiple care settings, Validity - The measure has been demonstrated to be valid (i.e. it measures what it purports to).f

Other items

Owner details

Reference number

862

Date of entry to library

2012-05-31 13:43:21

Owner (Organisation name)

Health Quality & Safety Commission, Indicator Project Team

Owner (Email contact)

richard.hamblin@hqsc.govt.nz

Creator (Organisation name)

National Health Board

Creator (Email contact)