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Hospital Unplanned and Unexpected Readmission Rates

Basic Facts

Stage of development


Potential or current usage

This measure can be a proxy of both the care received in the hospital and the coordination of care back to the outpatient setting and within the outpatient setting.

Brief overview of the measure

General description

Hospital planned and unexpected readmission rates are a measure of the effectiveness of the coordination of care.

Rationale for selection

The Health Quality and Safety Commission Indicator Project Expert Advisory Group selected this measure from the Institute for Healthcare Improvement (IHI) as an important measure to indicate if changes to improve patient flow through the system are negatively affecting care. While some readmissions are part of the planned care and are desirable, others may be an indication of a quality issue related to shortened length of stay and premature discharge, inadequate care, or lack of patient adherence to the care regimen following discharge from the hospital. The responsibility is placed with the initial facility/DHB. It is important to include measures such as this one that do not only reflect different sites of care (e.g. inpatient) but also cross boundaries, highlighting the interaction between the different parts of the system.

Type of measure


Domain(s) of quality


Application and interpretation of the measure

Stated intent of the measure

To measure the percentage of discharges readmitted within a set period in order to identify indications of a quality issue.

Caveats - Considerations

This is a fairly crude indicator that does not take into account the nature of unplanned readmission, and indeed whether there is appropriate care available in the community that may have prevented the need for admission. It is likely to be influenced by demographic factors, such as the proportion of older people within a district population and by existing levels of comorbidity.

Level of health care delivery/setting

Secondary care

Target population

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

Stratification by vulnerable populations

Stratification by ethnicity and socio economic status is useful.

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

Percentage (standardised) of discharges readmitted within a set period (attributed to the DHB of the initial discharge).

Numerator description

Casemix funded acute admissions (adm_typ in ('AA', 'AC', 'ZA', 'ZC', 'RL')) within 28 days of a prior publicly funded (MoH or DHB funded) discharge.

Numerator exclusions

Zero or one day stay initial admissions. ACC funded initial events. Short stay admissions are excluded as there is variable practice in whether these cases get admitted. ACC funded initial admissions are excluded as these would largely be contracted from private hospitals and attribution to DHB would be inappropriate. Filtering for casemix funded simplifies consistency with the denominator.

Denominator description

Casemix funded admissions

Denominator exclusions

Zero or one day stay initial admissions. ACC funded initial events

Time period


Criteria/standard for optimal performance

Patients who have their operation cancelled (for a non clinical reason) on the day of surgery should be readmitted within 28 days.

Data source

Numerator: NMDS Denominator: NMDS

Method of extraction

Each month, use admission information systems to identify patients who were discharged that month and also had a second admission within 28 days of the initial discharge date.

Appraisal of the measure

Availability of evidence to support application 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., Validity - The measure has been demonstrated to be valid (i.e. it measures what it purports to).

Other items

Owner details

Reference number


Date of entry to library

2012-05-31 14:35:19

Owner (Organisation name)

Health Quality and Safety Commission, Indicators project team

Owner (Email contact)


Creator (Organisation name)

Health Quality and Safety Commission, Indicators project team

Creator (Email contact)