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. 2017 Aug 7;6:1033. Originally published 2017 Jun 30. [Version 2] doi: 10.12688/f1000research.11637.2

Table 2. Definitions and data sources for all clinical outcome measures.

Health Level 7 (HL7) messages are used to transfer information between different healthcare IT systems.

Outcome measure Definition Source of data
Presence of AKI
complications		 Presence of:
      -      Hyperkalaemia
      -      Acidosis
      -      Uraemia
      -      Peripheral oedema
      -      Pulmonary oedema
During index admission		 Electronic/Paper note review,
HL7 data* aggregated within the
Streams-AKI data processor
Recovery of renal function Return to <120% index creatinine (as
defined by NHS diagnostic algorithm)
by the time of hospital discharge		 HL7 data aggregated within the
Streams-AKI data processor
Time to recovery of renal
function		 The time from AKI alert to recovery of
renal function (<120% index creatinine).		 HL7 data aggregated within the
Streams-AKI data processor
Progression of AKI stage Movement between AKI severity classes
following AKI alert and prior to hospital
discharge		 HL7 data aggregated within the
Streams-AKI data processor
Mortality Death in 30 days following AKI alert HL7 data aggregated within the
Streams-AKI data processor
Length of stay Time from AKI alert to hospital discharge HL7 data aggregated within the
Streams-AKI data processor
Admission to high acuity or
specialist renal inpatient bed		 Admission to:
      -      Acute Kidney Unit (AKU) or other
renal ward
      -      High Dependency Unit (HDU)
      -      Intensive Treatment Unit (ITU)
During index admission		 HL7 data aggregated within the
Streams-AKI data processor
Length of stay in high acuity
bed		 Length of stay on:
      -      AKU
      -      HDU
      -      ITU
During index admission		 HL7 data aggregated within the
Streams-AKI data processor
Requirement for immediate
temporary renal replacement
therapy		 Use of:
      -      Haemofiltration
      -      Haemodiafiltration
      -      Haemodialysis
      -      Peritoneal dialysis
After AKI alert, but during index admission		 HL7 data aggregated within the
Streams-AKI data processor/
Trust submissions to the Health
Episode Statistics- Admitted
Patient Care database
Requirement long-term renal
replacement therapy		 Use of:
      -      Haemofiltration
      -      Haemodiafiltration
      -      Haemodialysis
      -      Peritoneal dialysis
In 30 days following hospital discharge date		 The Trust’s Nephrology Clinical
Information Management
System (VitalData) and Health
Episode Statistics Admitted
Patient Care database.
Readmission to hospital Readmission to hospital in 30 days
following index admission discharge date		 HL7 data aggregated within the
Streams-AKI data processor
Follow-up renal function Last available creatinine obtained in
outpatients or on discharge following
another hospitalization between 90 and
365 days after index hospital discharge		 HL7 data aggregated within the
Streams-AKI data processor