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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Epidemiology and estimation of long-term surgical mortality
Scientific title
Validation and extension of a multivariable prediction model of perioperative mortality in
a national perioperative dataset
Secondary ID [1] 293864 0
ADHB A+ 7383
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Perioperative mortality 306326 0
Condition category
Condition code
Anaesthesiology 305411 305411 0 0
Other anaesthesiology
Surgery 305412 305412 0 0
Other surgery
Public Health 305440 305440 0 0

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
NZRISK will provide a multivariate risk model based on data from July 2011 to June 2016 of the New Zealand Ministry of Health National Minimum Dataset (NMDS. Covariates will include age, gender, ASA, acuity, specialty, surgical severity, ethnicity and cancer status.
Intervention code [1] 300125 0
Early Detection / Screening
Intervention code [2] 300155 0
Diagnosis / Prognosis
Comparator / control treatment
Observation - no control
Control group

Primary outcome [1] 304547 0
Postoperative Mortality at 30 days
Timepoint [1] 304547 0
30 days post surgery
Secondary outcome [1] 342925 0
Days Alive out of hospital
Timepoint [1] 342925 0
90 days
Secondary outcome [2] 346657 0
Postoperative Mortality at 90 days
Timepoint [2] 346657 0
90 days post surgery
Secondary outcome [3] 346670 0
Postoperative Mortality at 1 year
Timepoint [3] 346670 0
1 year post surgery
Secondary outcome [4] 346671 0
Postoperative Mortality at 2 year
Timepoint [4] 346671 0
2 years post surgery

Key inclusion criteria
undergoing a surgical procedure of any acuity (elective, expedited, urgent or emergency) in New Zealand
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Cardiac Surgery

Study design
Random sample
Statistical methods / analysis
Data of approximately 300,000 patients fromNational Minimum Dataset (NMDS) and National Mortality Registry. The dataset will be split for derivation and validation. We will use multivariable logistic regression with backward stepwise regression to derive the models.

ASA was handled as a categorical predictor with 5 categories. Operation type was mapped onto surgical grade in 4 categories of minor, intermediate, major and major-complex. Cancer was a bivariate variable for presence or absence of a cancer with potential to affect mortality. Acuity was categorical elective or acute. Age was handled as a continuous predictor.
We will use multivariable logistic regression with backward stepwise regression. Univariate analysis will be performed initially using chi-squared testing to test the relationship between each independent variable and 30-day mortality. All analyses will performed to validate a predictive model of 30-day mortality and then repeated to derive predictive models of 30-day, one-year and two-year mortality respectively. Variables that had more than 10% missing values were excluded from the analysis. Incremental improvements in the extended models by incorporating gender and ethnicity will be assessed by change in AUC and integrated discrimination improvement.
The predictive model will be derived from the full dataset and was then resampled using bootstrapping to evaluate performance. Reporting the results will be according to the TRIPOD statement.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 9520 0
New Zealand
State/province [1] 9520 0

Funding & Sponsors
Funding source category [1] 298483 0
Other Collaborative groups
Name [1] 298483 0
Precision Driven Health
Address [1] 298483 0
181 Grafton Road, Auckland 1024
Country [1] 298483 0
New Zealand
Primary sponsor type
Dr Douglas Campbell
Dept Anaesthesia and Perioperative Services.
Level 8, Support Building, Auckland City Hospital. Park Rd, Grafton, Auckland 1024
New Zealand
Secondary sponsor category [1] 297627 0
Name [1] 297627 0
Address [1] 297627 0
Country [1] 297627 0
Other collaborator category [1] 279911 0
Government body
Name [1] 279911 0
Auckland District Health Board
Address [1] 279911 0
Park Road
Auckland 1024
Country [1] 279911 0
New Zealand
Other collaborator category [2] 279912 0
Name [2] 279912 0
Professor Alan Merry
Address [2] 279912 0
Dept of Anaesthesiology, University of Auckland
Park Road
Auckland 1024
Country [2] 279912 0
New Zealand
Other collaborator category [3] 279914 0
Name [3] 279914 0
Associate Professor Tim Short
Address [3] 279914 0
Department of Anaesthesia and Perioperative Services
Auckland City Hospital
Level 8 Support Building
Park Road
Auckland 1024
Country [3] 279914 0
New Zealand

Ethics approval
Ethics application status
Ethics committee name [1] 299470 0
Health and Disability Ethics Committees
Ethics committee address [1] 299470 0
Ministry of Health
133 Molesworth Street
PO Box 5013
Ethics committee country [1] 299470 0
New Zealand
Date submitted for ethics approval [1] 299470 0
Approval date [1] 299470 0
Ethics approval number [1] 299470 0

Brief summary
Currently, there is no widely used clinical tool for anaesthestists to predict perioperative mortality that has been validated in New Zealand patients. We aim to validate the Surgical Outcome Risk Tool (SORT), a parsimonious, 6 risk factor multivariate model used in the UK, in a New Zealand cohort. We also aim to extend the model to include gender and ethnicity to tailor the model to New Zealand conditions. We will also aim to derive extended models incorporating one and two year mortality as well as 30 day mortality.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 80514 0
Dr Douglas Campbell
Address 80514 0
Department Anaesthesia and Perioperative Services
Level 8, Auckland City Hospital
Park Road
Grafton, Auckland 1024
Country 80514 0
New Zealand
Phone 80514 0
Fax 80514 0
Email 80514 0
Contact person for public queries
Name 80515 0
Ms Davina McAllister
Address 80515 0
Anaesthesia and Perioperative Services
Level 8, Auckland City Hospital
Park Road
Grafton, Auckland 1024
Country 80515 0
New Zealand
Phone 80515 0
Fax 80515 0
Email 80515 0
Contact person for scientific queries
Name 80516 0
Dr Douglas Campbell
Address 80516 0
Anaesthesia and Perioperative Services
Level 8, Auckland City Hospital
Park Road
Grafton, Auckland 1024
Country 80516 0
New Zealand
Phone 80516 0
Fax 80516 0
Email 80516 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary