International Surgical Outcomes Study (ISOS)

ISRCTN	ISRCTN51817007
DOI	https://doi.org/10.1186/ISRCTN51817007
Protocol serial number	N/A
Sponsor	Queen Mary University of London (UK)
Funder	Nestlé Health Science SA.

Submission date: 11/12/2013
Registration date: 03/01/2014
Last edited: 29/06/2021

Recruitment status: No longer recruiting
Overall study status: Completed
Condition category: Surgery

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Plain English summary of protocol

Background and study aims
The findings of a recent study have suggested that deaths after surgery may be more frequent than previously thought, suggesting some may be preventable. However, there are limited available data describing complications, and therefore why patients die, following surgery. The aim of this study is to confirm the incidence of 30-day in-hospital complications following elective in-patient surgery.

Who can participate?
Adult patients aged 18 years or older undergoing elective surgery and staying overnight in hospital during the study period.

What does the study involve?
Participants will not receive any additional treatments or medicines as part of this study. Patients will be followed up for information describing outcomes after surgery until they leave hospital.

What are the possible benefits and risks of participating?
There are no risks of taking part and no changes to your treatment.

Where is the study run from?
The study is taking place in hundreds of hospitals around the world.

When is the study starting and how long is it expected to run for?
The study will take place during the spring of 2014.

Who is funding the study?
The study is funded by the Nestle Health Science SA.

Who is the main contact?
Professor Rupert Pearse - Chief Investigator
Marta Januszewska - Study Coordinator

Contact information

Prof Rupert Pearse
Scientific

Adult Critical Care Unit
Royal London Hospital
Whitechapel
London
E1 1BB
United Kingdom

Mr Richard Haslop
Scientific

Adult Critical Care Research Office
Room 14
Central Tower
Royal London Hospital
Whitechapel
London
E1 1BB
United Kingdom

Study information

Primary study design	Observational
Study design	International multicentre observational 7-day cohort study
Secondary study design	Cohort study
Study type	Participant information sheet
Scientific title	International observational 7-day cohort study of complications following elective surgery
Study acronym	ISOS
Study objectives	To confirm the incidence of 30-day in-hospital complications following elective in-patient surgery. On 21/07/2015 the overall trial end date was changed from 01/04/2016 to 09/07/2014.
Ethics approval(s)	NRES Committee Yorkshire & The Humber - Humber Bridge, 20/11/2013, REC ref: 13/YH/0371
Health condition(s) or problem(s) studied	Elective surgery
Intervention	This is an observational study. Patients will be followed up until hospital discharge or for a maximum of 30 days, whichever is shorter.
Intervention type	Procedure/Surgery
Primary outcome measure(s)	To confirm the incidence of 30-day in-hospital complications following elective in-patient surgery.
Key secondary outcome measure(s)	1. In-hospital all-cause mortality (censored at 30 days following surgery) 2. Admission to critical care (within 30 days following surgery) 3. Duration of hospital stay (duration of primary hospital stay after surgery)
Completion date	09/07/2014

Eligibility

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Sex	All
Target sample size at registration	50000
Key inclusion criteria	All adult patients (aged 18 years or older) undergoing elective surgery in a participating hospital during the seven-day cohort period with a planned overnight stay.
Key exclusion criteria	Patients undergoing emergency surgery, planned day-case surgery or radiological procedures
Date of first enrolment	01/04/2014
Date of final enrolment	09/07/2014

Locations

Countries of recruitment

United Kingdom
England
Australia
Austria
Belgium
Brazil
Canada
China
Egypt
Germany
Greece
Hong Kong
India
Indonesia
Iraq
Italy
Malaysia
Mexico
New Zealand
Nigeria
Pakistan
Portugal
Romania
Russian Federation
Singapore
South Africa
Spain
Sweden
Switzerland
United States of America

Study participating centre

Royal London Hospital

London
E1 1BB
United Kingdom

Results and Publications

Individual participant data (IPD) Intention to share	Yes
IPD sharing plan summary	Available on request
IPD sharing plan

Study outputs

Output type	Details	Date created	Date added	Peer reviewed?	Patient-facing?
Results article	results	31/10/2016		Yes	No
Results article	India results	01/05/2021	29/06/2021	Yes	No
HRA research summary			28/06/2023	No	No
Participant information sheet	Participant information sheet	11/11/2025	11/11/2025	No	Yes
Study website	Study website	11/11/2025	11/11/2025	No	Yes

Editorial Notes

29/06/2021: Publication reference added.
11/12/2017: Publication reference added.