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ComorbiditiesAANCT04109001

Method of Measuring Comorbidity to Predict Outcome After Intensive Care

An observational study of Comorbidities and Critical Care, run by Uppsala University.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

In this study the investigators will validate the impact of comorbidity on readmission to intensive care unit (ICU) and mortality after ICU and which method of measuring comorbidity that is most predictive. Read more about this study

Who is it for?
Any age
Conditions the study is for
Comorbidities, Critical Care
How many people
223,495 participants
Where
No sites listed yet
Study dates
1 Jan 2005to 31 Dec 2015
How long will I take part?
5 Years
Phase
Observational
Are there results?
None posted in the registry

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages Any age
  • All sexes
  • No healthy volunteers
  • Child, Adult, Older adult

Study population: All critical care patients' registries in SIR during the years 2005 to 2012 with valid personal identity number.

Who may be able to join

  • All critical care patients' registries in SIR during the years 2005 to 2012
  • Valid personal identity number

Who cannot join

  • Age 16 and older
  • No valid personal identity number

About this study

Official title: Method of Measuring Comorbidity and Time-point to Predict Readmission and Mortality of Intensive Care Patients: an Observational Study Using Linked Data From National Registers of Hospital Care and Cause of Death

In this study the investigators will validate the impact of comorbidity on readmission to intensive care unit (ICU) and mortality after ICU and which method of measuring comorbidity that is most predictive.

The study population included all critical care patients' registries in Swedish intensive care registry (SIR) during the years 2005 to 2012 with valid personal identity number. Data from Statistics Sweden och National Board of Health and Welfare were linked to data from SIR and de-identified.

Read more

Hospital discharge diagnoses from five year preceding the index date for the ICU admission were extracted. A composite outcome of death and readmission will be analyzed.

Analyzes with cox proportional-hazards regression, time to event, on the training data set year 2005-2010 The study population will be split in a training data set (2005-10) and a test data set (2011-12) for validating our prognostic model. The predictive ability in the test data set were evaluated based on discrimination, AUC (C index), Calibration and Brier score.

Read the detailed description

In this study the investigators will validate the impact of comorbidity on readmission to intensive care unit (ICU) and mortality after ICU and which method of measuring comorbidity and in which time-point it is most predictive.

The study population includes all critical care patients' registries in Swedish intensive care registry (SIR) during the years 2005 to 2012 with valid personal identity number. SIR delivers the population to Statistics Sweden directly or via the client for further delivery to Statistics Sweden. For all individuals in the population, data are collected from registers at Statistics Sweden. Statistics Sweden supplies social security numbers and serial numbers to the National Board of Health for further data collection there. The National Board of Health and Welfare delivers the data sample to the client who sends it to Statistics Sweden for collaboration and anonymous. All data material is stored unidentified in the MONA database where only persons connected to the project have access to the material.

The data set containing 293 342 observations and 223 495 unique individuals. Observations which is totally covered in time by another observation are excluded. Two consecutive observations with less than 24 hours between them consider as the same visit. The final set of dates consists of 273 741 observations (223 495 individuals).

Patients with recurrent ICU stays during the study period were considered as recurrent events that are not independent of each other. The interval between ICU discharge and readmission was used both as an outcome variable and to characterize the patient at the time to admission. In the analyzes the dependency between multiple admissions for the same individual was handled using a robust sandwich estimator. Every ICU stay was included in the study but handled as a time-updated exposure.

A composite outcome of death and readmission will be analyzed. Death and readmission will also be analyzed separately. Follow-up starts at admission. A binary status variable (no/yes) is created reflecting if the outcome has happened or not together with a corresponding time variable. For each admission the follow-up ends with readmission, death or end of study (2016-12-31) whichever comes first.

Hospital discharge diagnoses from five years preceding the index date for the ICU admission were extracted from the National Board of Health and Welfare and linked to the SIR data using exact person-based linkage. The Charlson comorbidity index was calculated based on this information. A different categorization of comorbidity was also performed as modified based from the categorization proposed by Elixhauser. For each of 36 defined comorbidity categories the number of admissions with a primary diagnosis, the number of admissions with a secondary diagnosis, the total length of stay with a primary diagnosis, and the interval from the last admission with the comorbidity condition as a primary diagnosis, were calculated.

The underlying condition causing ICU admission was categorized according to diagnosis and admitting department.

Analyzes with cox proportional-hazards regression, time to event, on the training data set year 2005-2010 Charlson comorbidity index (CCI) categorical 0, 1, 2, 3-5, 6-9, 10-17 Elixhauser 36 categories

  1. Number of primary diagnosis (count)
  2. Number of secondary diagnosis (count)
  3. Total care time primary diagnosis (count)
  4. Time interval from latest primary diagnosis (missing, count)

Analyzes

A Age + sex B A + CCI C A + a D A + a + b E A + a + b + c F A + a + b + c + d

There was by definition no missing data in the comorbidity variables. Missing information concerning age and sex were minimal and did not require imputation. The proportional hazards assumption was checked using the Kaplan-Meier Curves.

The study population will be split in a training data set (2005-10) and a test data set (2011-12) for validating our prognostic model. The predictive ability in the test data set were evaluated based on discrimination, area under curve (AUC) (C index), Calibration and Brier score.

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. The ability of comorbidity to predict death after intensive care

    A composite outcome of death and readmission will be analyzed. Death and readmission will also be analyzed separately. Follow-up starts at admission. A binary status variable (no/yes) is created reflecting if the outcome has happened or not together with a corresponding time variable.

    Measured: For each admission the follow-up ends with readmission, death or end of study (2016-12-31) whichever comes first.

  2. The ability of comorbidity to predict readmission after intensive care

    A composite outcome of death and readmission will be analyzed. Death and readmission will also be analyzed separately. Follow-up starts at admission. A binary status variable (no/yes) is created reflecting if the outcome has happened or not together with a corresponding time variable.

    Measured: For each admission the follow-up ends with readmission, death or end of study (2016-12-31) whichever comes first.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted30 Sep 2019
  2. Study start1 Jan 2005
  3. Primary completion31 Dec 2015
  4. Study completion31 Dec 2015

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Other
Enrolment
223,495 participants (actual)
Target duration
5 Years
IDs, dates and publications
ClinicalTrials.gov ID
NCT04109001
Sponsor's protocol ID
Anna Aronsson
Acronym
AA
Status last verified
Jan 2020
First submitted
26 Sep 2019
Last updated
10 Jan 2020
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: To minimize the risk of data coming into the wrong hands, after linking the data sources personal numbers replaced with anonymous serial numbers. The data then does not leave statistic Sweden and the database MONA, and are only available to qualified researchers. All analysis and statistical processing is thus done at Statistics Sweden and only results can be obtained from there. All reporting is done at group level. If the study wants to be replicated, data from the same period can be extracted from the above mentioned register.

Publications

  • Christensen S, Johansen MB, Christiansen CF, Jensen R, Lemeshow S. Comparison of Charlson comorbidity index with SAPS and APACHE scores for prediction of mortality following intensive care. Clin Epidemiol. 2011;3:203-11. doi: 10.2147/CLEP.S20247. Epub 2011 Jun 17.

    PubMed 21750629
  • Cook RJ, Lawless JF. Analysis of repeated events. Stat Methods Med Res. 2002 Apr;11(2):141-66. doi: 10.1191/0962280202sm278ra.

    PubMed 12040694
  • Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care. 1998 Jan;36(1):8-27. doi: 10.1097/00005650-199801000-00004.

    PubMed 9431328
  • Aronsson Dannewitz A, Svennblad B, Michaelsson K, Lipcsey M, Gedeborg R. Optimized diagnosis-based comorbidity measures for all-cause mortality prediction in a national population-based ICU population. Crit Care. 2022 Oct 6;26(1):306. doi: 10.1186/s13054-022-04172-0.

    PubMed 36203163

Questions about this trial

What is this clinical trial studying?

An observational study of Comorbidities and Critical Care, run by Uppsala University.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 2 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 10 Jan 2020. Status can change between updates, so confirm with the study contact before making plans.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

The ability of comorbidity to predict death after intensive care (time frame: For each admission the follow-up ends with readmission, death or end of study (2016-12-31) whichever comes first.). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04109001, which also lists 4 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 10 Jan 2020.

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