Pre-ICU Hospital Length of Stay and 30-day Mortality in the Very Old: a National Cohort of 315 042 ICU Admissions

April 29, 2026 updated by: Uppsala University
How does waiting in hospital before intensive care affect older patients?Patients who become seriously ill are sometimes admitted to a regular hospital ward first, and only transferred to the intensive care unit (ICU) when their condition worsens. The longer this wait, the higher the risk of dying within the following weeks. The number of very old patients (aged 80 and over) considered for ICU care is rising, and decisions about whether and when to admit them are difficult. It is not known whether the wait before ICU matters as much in this age group as in younger patients, or whether it carries different weight when judging how serious their illness is. Over 315,000 adults admitted to Swedish ICUs between 2005 and 2016 were examined, and statistical models were used to estimate how the risk of dying within 30 days depends on age and on the time spent in hospital before reaching the ICU.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Background. Hospital length of stay before intensive care unit (ICU) admission (pre-ICU LOS) is an established prognostic marker for short-term mortality in critically ill patients: longer pre-ICU stays are generally associated with higher subsequent mortality. Whether this association holds uniformly across the adult age range, or is modified by age, is not established. The question is clinically relevant for the very old (≥80 years), an increasing share of ICU populations, in whom triage decisions are particularly consequential. How age modifies the association between pre-ICU LOS and 30-day mortality will be examined in a national cohort of adult ICU patients.

Design and setting. A retrospective cohort study using prospectively collected data from the Swedish Intensive Care Registry (SIR) linked to the Swedish National Patient Registry (NPR) and the Swedish Cause of Death Registry. The study will include all adult (≥18 years) first ICU admissions reported to SIR between 1 January 2005 and 31 December 2016. Records will be linked across registries via the Swedish personal identification number; patients without a valid number are excluded by the data holders before delivery. The study has been approved by the Regional Ethics Committee of Uppsala (DNR 2016/421), which also waived informed consent.

Exposure. Pre-ICU LOS is the time in hospital between hospital and ICU admission, with zero for direct-from-emergency-department admissions. Where missing, pre-ICU LOS will be reconstructed from NPR care episodes adjacent to the ICU episode.

Outcome. All-cause mortality within 30 days of ICU admission, as a binary endpoint. Follow-up is complete by registry design.

Analysis. The primary analysis will be a binary logistic regression on 30-day mortality, allowing for non-linear effects of age, pre-ICU LOS, and the Quan-updated Charlson comorbidity index, with sex as a binary factor. Pairwise interactions between age and pre-ICU LOS, pre-ICU LOS and sex, and age and sex will be included. The adjustment set is chosen a priori from a directed acyclic graph; acute physiology at admission (SAPS3 Box III) is excluded as a plausible post-exposure mediator. Marginal predicted 30-day mortality and within- and between-age risk differences will be estimated by G-computation at a range of clinically meaningful pre-ICU LOS values across age deciles. Uncertainty will be quantified by nonparametric bootstrap with percentile 95 % confidence intervals. Sensitivity analyses will examine the primary findings under categorical specifications of age and pre-ICU LOS, and after adjustment for SAPS3 Box III with multiple imputation of missing values.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
315042

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Sweden
      • Uppsala, Sweden
        • Uppsala University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Probability Sample

Study Population

Patient admitted to a Swedish ICU that reported the admission to the Swedish intensive care registry.

Description

Inclusion Criteria:

  • Patient admitted to a Swedish ICU that reported the admission to the Swedish intensive care registry.

Exclusion Criteria:

-

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Patients admitted to Swedish ICUs
Patients admitted to Swedish ICUs between 2005 and 2017
Other: Time in hospital before ICU admission.
Time in hospital before ICU admission by age groups.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Mortality
Time Frame: 30 day
30 day

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Uppsala University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Region Dalarna

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 30, 2019

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 30, 2019

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 30, 2019

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
April 29, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 29, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 6, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 6, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 29, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Age-length of stay

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

The data is available from the registries according to their rules, that usually involve at least a permission by the Swedish ethical review authority and a fee. The data is also available from the researchers with permission from the Swedish ethical review authority, the Uppsala University and provided that the General data protection act by the European Union is followed.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings