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Downloaded from Epidemiology of Accidental Hypothermia in Denmark – a Nationwide Cohort Study Journal: BMJ Open ManuscriptFor ID peerbmjopen-2020-046806 review only Article Type: Original research Date Submitted by the 09-Nov-2020 Author: Complete List of Authors: Wiberg, Sebastian; Rigshospitalet, Department of Cardiology Mortensen, Asmus; Bispebjerg and Frederiksberg Hospital, Department of Anaesthesia and Intensive Care Kjærgaarda, Jesper; Rigshospitalet, Department of Cardiology Hassager, Christian; Rigshospitalet, Cardiology Wanscher, Michael; Rigshospitalet, Department of CardioThoracic Anaesthesiology ACCIDENT & EMERGENCY MEDICINE, EPIDEMIOLOGY, GENERAL Keywords: MEDICINE (see Internal Medicine) http://bmjopen.bmj.com/ on September 25, 2021 by guest. Protected copyright. For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml Page 1 of 22 BMJ Open 1 2 3 4 BMJ Open: first published as 10.1136/bmjopen-2020-046806 on 31 May 2021. 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Protected copyright. 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml BMJ Open Page 2 of 22 1 2 3 Epidemiology of Accidental Hypothermia in Denmark – a Nationwide 4 BMJ Open: first published as 10.1136/bmjopen-2020-046806 on 31 May 2021. Downloaded from 5 Cohort Study 6 7 8 9 Authors 10 Sebastian Wiberg* MD PhD1, Asmus Friborg Mortensen* MD2, Jesper Kjaergaard, 11 12 MD PhD DMSc1, Christian Hassager MD DMSc1, Michael Wanscher MD PhD3. 13 14 15 16 Affiliations 17 1) Department of Cardiology, The Heart Centre, Copenhagen University 18 For peer review only 19 Hospital Rigshospitalet 20 21 2) Department of Anaesthesia and Intensive Care, Bispebjerg and 22 23 Frederiksberg Hospital, University of Copenhagen, Denmark 24 3) Department of Cardiothoracic Anaesthesiology, The Heart Centre, 25 26 Copenhagen University Hospital Rigshospitalet, Denmark 27 28 29 30 Corresponding Author 31 Sebastian Wiberg, MD, PhD 32 33 Department of Cardiology 34 35 The Heart Centre 36 http://bmjopen.bmj.com/ 37 Copenhagen University Hospital Rigshospitalet 38 [email protected] 39 40 41 42 *) Equal author contribution 43 44 on September 25, 2021 by guest. Protected copyright. 45 46 Research Question 47 To investigate the reported incidence of accidental hypothermia in a nationwide 48 49 registry, and to further investigate the associations between accidental 50 51 hypothermia and the associated outcomes. 52 53 54 Study Design 55 56 Retrospective cohort study 57 58 59 60 1 For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml Page 3 of 22 BMJ Open 1 2 3 Abstract 4 BMJ Open: first published as 10.1136/bmjopen-2020-046806 on 31 May 2021. Downloaded from 5 Objectives 6 7 To investigate the reported incidence of accidental hypothermia (AH) in a 8 9 nationwide registry, and to further investigate the associations between 10 accidental hypothermia and the associated outcomes. 11 12 13 14 Design 15 16 Nationwide retrospective cohort study 17 18 For peer review only 19 Participants 20 21 All adult patients admitted to hospitals in Denmark with a diagnosis of AH from 22 23 January 1996 to November 2016. Patients were identified as all patients 24 admitted with an ICD-10 code of T689. Other recorded diagnoses were included 25 26 in the analyses. 27 28 29 30 Primary and secondary outcome measures 31 The primary outcome was one-year fatality. 32 33 34 35 Results 36 http://bmjopen.bmj.com/ 37 Throughout the inclusion period, 5242 patients were admitted with a diagnosis 38 of AH, corresponding to an average annual incidence of 4.4 (range 2.9 – 6.4) per 39 40 100,000 inhabitants. A total of 2230 (43%) had AH recorded as the primary 41 42 diagnosis without any recorded secondary diagnoses (Primary AH), 1336 (25%) 43 had AH recorded as the primary diagnosis with other recorded secondary 44 on September 25, 2021 by guest. Protected copyright. 45 46 diagnoses (Secondary AH, type I), and 1676 (32%) had AH recorded as a 47 secondary diagnosis with another recorded primary diagnosis (Secondary AH, 48 49 type II). Alcohol intoxication was the most prevalent diagnosis associated to AH. 50 51 Overall one-year fatality was 27%. In patients with primary AH, one-year fatality 52 53 was 22%, compared to 26% in patients with secondary AH type I, and 35% in 54 patients with secondary AH type II (p < 0.001). 55 56 57 58 Conclusions 59 60 2 For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml BMJ Open Page 4 of 22 1 2 3 The incidence of AH was 4.4 per 100.000 per year in the period from 1995 to 4 BMJ Open: first published as 10.1136/bmjopen-2020-046806 on 31 May 2021. Downloaded from 5 2016, and the diagnosis was associated with a high comorbidity burden. AH 6 7 patients had a one-year fatality of 27%. In otherwise healthy patients with 8 9 primary AH, the one-year fatality was 22%. 10 11 12 Article Summary 13 14 Strengths and Limitations of this study 15 16 - Largest contemporary study to investigate the incidence, comorbidity 17 burden and outcome in patients diagnosed with AH. 18 For peer review only 19 - Data originated from national registers, which limited the data 20 21 granularity to what has been presented in the present paper. 22 23 24 Funding 25 26 The study was funded by Trygfonden - Accidental Hypothermia (ID: 117579). 27 28 The sponsor had no involvement in study design, collection, analysis and 29 30 interpretation of data, writing of the manuscript or decision to submit the 31 manuscript for publication. 32 33 34 35 Competing interests 36 http://bmjopen.bmj.com/ 37 None 38 39 40 41 42 43 44 on September 25, 2021 by guest. Protected copyright. 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 3 For peer review only - http://bmjopen.bmj.com/site/about/guidelines.xhtml Page 5 of 22 BMJ Open 1 2 3 Introduction 4 BMJ Open: first published as 10.1136/bmjopen-2020-046806 on 31 May 2021. Downloaded from 5 Accidental hypothermia (AH), defined as an involuntary drop in core body 6 7 temperature below 35C, is a serious condition with considerable fatality1,2.