Drowning in Denmark: A Six-year Registry-based Study of Fatal and Non-fatal Drowning

Drowning in Denmark: A Danish Nationwide Six-year Registry-based Study on Aetiology, Incidence, Survival, and Spatial Distribution of Fatal and Non-fatal Drowning Incidents

Within a six-year period from 2016-2021, this retrospective cohort study aims to report: 1) the national incidence of fatal and non-fatal drowning incidents attended by the Danish Emergency Medical Services (EMS), 2) Risk factors associated with 30-day mortality, 3) Spatial distribution drowning incidents presented on a map of Denmark stratified for 30-day survival.

Furthermore, the investigators will follow the Utstein Style For Drowning (USFD) recommended guidelines for uniform reporting of data from drowning.

Study Overview

• Status: Completed
• Conditions: Drowning
• Intervention / Treatment: Other: Drowning incident

Detailed Description

Purpose

The purpose of this study is to establish recommendations towards specific educational, preventative, rescue, or treatment strategies to reduce the number of fatal and non-fatal drowning incidents in Denmark (e.g., campaigns targeting high-risk groups, or fencing, allocating rescue equipment, or establishing lifeguard stations in high-risk areas).

Objectives

The primary objective is to estimate the yearly incidence of fatal and non-fatal drowning incidents in Denmark treated by the Emergency Medical Services from 2016 to 2023. The secondary objective is to explore risk factors associated with 30-day mortality. A directed acyclic graph will be developed [18]. For each risk factor, we will test the following hypothesis.

Hypothesis

An increased risk of fatal drowning associated with lack of supervision Drowning patients who are found in the water, where the drowning incident itself was unobserved, are at higher risk of fatal drowning, associated with increased submersion time and EMS response time.

An increased risk of fatal drowning associated with prolonged submersion time Drowning patients with increased submersion time are at higher risk of fatal drowning, associated with more severe hypoxic damage and cardiorespiratory arrest.

An increased risk of fatal drowning associated with alcohol and substance use Drowning patients influenced by alcohol or other substances are at higher risk of fatal drowning because of impaired judgment and coordination.

An increased risk of fatal drowning associated with male sex Males are at higher risk of fatal drowning, associated with increased exposure to water and risk-taking behaviour such as swimming alone, drinking alcohol before swimming alone, and boating.

An increased risk of drowning associated with age Young children (less than five years) are at higher risk of drowning, associated with a lack of swimming skills. However, they tend to be non-fatal as the lapse in supervision is often momentary, allowing for a brief submersion.

Adolescents and young adults (15-25 years) are at higher risk of fatal drowning, associated with risk-taking behaviour.

Adults more than 60 years old are at higher risk of fatal drowning, associated with comorbidities (e.g., heart attacks and STROKE leading to a temporary loss of consciousness in the water) and unwitnessed events.

An increased risk of fatal drowning associated with the type of drowning location Drowning patients in natural bodies of water (e.g., harbours, oceans, lakes) are at higher risk of fatal drowning associated with currents, decreased visibility, uneven terrain, and unwitnessed events.

Study design

A nationwide registry-based study with data from the Danish Prehospital Drowning Data from 2016 to 2023 and follow-up on mortality 30 days after the drowning incident.

• Study Type: Observational
• Enrollment (Actual): 1204

Contacts and Locations

• Study Contact: Name: Niklas Breindahl, MD; Phone Number: +4528566410; Email: niklas.breindahl@regionh.dk
• Study Contact Backup: Name: Helle C Christensen, MD, PhD; Phone Number: +4521673452; Email: helle.collatz.christensen.02@regionh.dk

Study Locations

• Denmark
  • Region Zealand
    • Næstved, Region Zealand, Denmark, 4700
      • Prehospital Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

All Danish citizens suffering a drowning incident in the period from 2016-2021 with subsequent contact to the Danish EMS.

Description

Inclusion criteria:

• The patient must have been experiencing respiratory impairment from submersion or immersion in liquid AND
• The patient must have been in contact with the Danish EMS.

Exclusion criteria:

• Patients were excluded if it was unclear that the incident involved submersion or immersion with aspiration of liquid (e.g., a patient found dead in the bathtub).
• Patients were excluded if the incident involved submersion or immersion with aspiration, but the patient did not experience respiratory impairment. For example, if the patient was rescued from the water without signs of respiratory impairment, or if the respondent reported "a few coughs" or "voluntary cough".

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Fatal drowning; Fatal drowning incident where the patient died because of the drowning process	Other: Drowning incident; Drowning is defined by the WHO in 2002 as "the process of experiencing respiratory impairment from submersion or immersion in liquid"
Non-fatal drowning; Non-fatal drowning incident where the patient was drowning and can be ascertained to have been experiencing either mild, moderate, or severe respiratory impairment immediately after the drowning process ended but survived.	Other: Drowning incident; Drowning is defined by the WHO in 2002 as "the process of experiencing respiratory impairment from submersion or immersion in liquid"

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fatal and non-fatal annual incidence from 2016-2021	The primary objective is to estimate the annual incidence of fatal and non-fatal drowning incidents in Denmark treated by the EMS from 2016 to 2021 and will be reported as the annual number of cases.	Counts of fatal and non-fatal drowning incidents will be obtained between 2016-2021.
Fatal vs. non-fatal incidence ratios per 1,000 person-years from 2016-2021	The primary objective is to estimate the annual incidence of fatal and non-fatal drowning incidents in Denmark treated by the EMS from 2016 to 2021 and will be reported as the annual number of cases per 1,000 person-years.	Counts of fatal and non-fatal drowning incidents will be obtained between 2016-2021.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Map of fatal and non-fatal drowning incidents in Denmark from 2016-2021	Showing a map of geographical localization of drowning in Denmark in the study period indicating 30-day mortality and survival	6-year period from 2016-2021.
Association between risk factors and 30-day mortality	This outcome will explore potential risk factors associated with 30-day mortality after a drowning incident. The following risk factors will be analysed using Cox proportional hazards regression and presented as hazard ratios (HR) with 95% confidence intervals (CIs): lack of supervision, prolonged submersion time, alcohol or substance use, male sex, age, and drowning location.	6-year period from 2016-2021.

Collaborators and Investigators

• Sponsor: Prehospital Center, Region Zealand
• Investigators: Principal Investigator: Niklas Breindahl, MD, Prehospital Center, Region Zealand

Publications and helpful links

General Publications

• Weiss J; American Academy of Pediatrics Committee on Injury, Violence, and Poison Prevention. Prevention of drowning. Pediatrics. 2010 Jul;126(1):e253-62. doi: 10.1542/peds.2010-1265. Epub 2010 May 24.
• Schmidt AC, Sempsrott JR, Szpilman D, Queiroga AC, Davison MS, Zeigler RJ, McAlister SJ. The use of non-uniform drowning terminology: a follow-up study. Scand J Trauma Resusc Emerg Med. 2017 Jul 17;25(1):72. doi: 10.1186/s13049-017-0405-x.
• Papa L, Hoelle R, Idris A. Systematic review of definitions for drowning incidents. Resuscitation. 2005 Jun;65(3):255-64. doi: 10.1016/j.resuscitation.2004.11.030.
• Lu TH, Lunetta P, Walker S. Quality of cause-of-death reporting using ICD-10 drowning codes: a descriptive study of 69 countries. BMC Med Res Methodol. 2010 Apr 8;10:30. doi: 10.1186/1471-2288-10-30.
• Steensberg J. Epidemiology of accidental drowning in Denmark 1989-1993. Accid Anal Prev. 1998 Nov;30(6):755-62. doi: 10.1016/s0001-4575(98)00028-1.
• Mackie IJ. Patterns of drowning in Australia, 1992-1997. Med J Aust. 1999 Dec 6-20;171(11-12):587-90. doi: 10.5694/j.1326-5377.1999.tb123808.x.
• Truhlar A, Deakin CD, Soar J, Khalifa GE, Alfonzo A, Bierens JJ, Brattebo G, Brugger H, Dunning J, Hunyadi-Anticevic S, Koster RW, Lockey DJ, Lott C, Paal P, Perkins GD, Sandroni C, Thies KC, Zideman DA, Nolan JP; Cardiac arrest in special circumstances section Collaborators. European Resuscitation Council Guidelines for Resuscitation 2015: Section 4. Cardiac arrest in special circumstances. Resuscitation. 2015 Oct;95:148-201. doi: 10.1016/j.resuscitation.2015.07.017. Epub 2015 Oct 15. No abstract available.
• Venema AM, Groothoff JW, Bierens JJ. The role of bystanders during rescue and resuscitation of drowning victims. Resuscitation. 2010 Apr;81(4):434-9. doi: 10.1016/j.resuscitation.2010.01.005. Epub 2010 Feb 10.
• Idris AH, Berg RA, Bierens J, Bossaert L, Branche CM, Gabrielli A, Graves SA, Handley AJ, Hoelle R, Morley PT, Papa L, Pepe PE, Quan L, Szpilman D, Wigginton JG, Modell JH; American Heart Association. Recommended guidelines for uniform reporting of data from drowning: the "Utstein style". Circulation. 2003 Nov 18;108(20):2565-74. doi: 10.1161/01.CIR.0000099581.70012.68. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2016
• Primary Completion (Actual): January 31, 2022
• Study Completion (Actual): January 31, 2022

Study Registration Dates

• First Submitted: May 29, 2022
• First Submitted That Met QC Criteria: June 16, 2022
• First Posted (Actual): June 21, 2022

Study Record Updates

• Last Update Posted (Actual): March 28, 2024
• Last Update Submitted That Met QC Criteria: March 26, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Retrospective; Utstein; Drowning; Register study; Non-fatal; Reigstry-based study
• Additional Relevant MeSH Terms: Pathologic Processes; Wounds and Injuries; Death; Drowning
• Other Study ID Numbers: DROWN_NONFATAL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No