- Email: [email protected]
Micromorts - what is the risk?
Available online at www.sciencedirect.com
British Journal of Oral and Maxillofacial Surgery 54 (2016) 230–231
Short communication
Micromorts - what is the risk? A.M. Fry a,∗ , A. Harrison b , M. Daigneault b a
Department of Oral and Maxillofacial Surgery, Sheffield Teaching Hospitals NHS Foundation Trust, Charles Clifford Dental Hospital, 76 Wellesley Rd, Sheffield, South Yorkshire S10 2SZ b The School of Clinical Dentistry, The University of Sheffield, 76 Wellesley Rd, Sheffield, South Yorkshire S10 2SZ Accepted 20 November 2015 Available online 30 December 2015
Abstract The effective communication of risk, which is central to the process of consent, can be difficult, and can be hard for patients to understand. We introduce the potential utility of the micromort, a unit of risk defined as a one-in-a-million chance of sudden death, which allows clinicians to compare the risks of an intervention with those of different activities, making them easier to understand. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Mortality; Risk; Oncology; Consent; Micromort
Introduction The effective communication of risk is central to the process of consent, defined by the General Medical Council as good medical practice. Several methods have been used to describe risk - for example, a risk of one in 1000 is termed “uncommon” or is equivalent to “someone in your village”.1 Percentage risks can be difficult for some patients to understand, but whichever method is used, the way in which the information is presented can have a profound effect on the decision made. Many patients find it helpful to have comparators.2 A micromort is a unit defined as a one-in-a-million risk of sudden death.3 A single micromort is roughly the normal daily risk of death from external causes for the general population in Europe, based on figures from the Office for National Statistics in 2012, and it provides a straightforward measure that can be used to compare the risks involved in different activities. A general anaesthetic, for example, has a reported risk of death of around 1 in 100 000
∗
Corresponding author. E-mail address: [email protected] (A.M. Fry).
Table 1 Number of micromorts associated with different interventions and recreational activities. Micromorts Interventions: Primary chemoradiotherapy for squamous cell carcinoma of the head and neck6 Postoperative chemoradiotherapy7 Microvascular reconstruction of the head and neck8 Tracheostomy9 Bimaxillary osteotomy10 Single jaw osteotomy10 General anaesthetic4 Recreational activities: Sky diving5 Fishing11 Rock climbing11 Horse riding11
52 132 17 544 10 000 7576 2300 1600 10 10/jump 92/year 66/year 297/year
(10 micromorts),4 which is the same as that quoted by the British Parachute Association for a single jump by an experienced sky diver.5 Mortality rates for operations and medical treatments can readily be converted into micromorts and used for comparison (Table 1).6–11
http://dx.doi.org/10.1016/j.bjoms.2015.11.023 0266-4356/© 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
A.M. Fry et al. / British Journal of Oral and Maxillofacial Surgery 54 (2016) 230–231
231
Fig. 1. Graph to show the comparable levels of risk, measured in micromorts, for different interventions.
Discussion Mortality rates quoted for populations in general can be of limited value for individual patients, so risks have been stratified to identify those at greatest risk. With further statistical evaluation it should be possible to allocate micromorts according to personal risk factors and coexisting conditions. A similar approach could also provide a standard means of presenting comparable outcome data for individual surgeons. However, the use of micromorts has limitations. As they are a measure of the risk of death only, the cause of death must be clearly defined, and as many decisions require a tradeoff between harm and benefit,2 they could be misleading if viewed in isolation. They cannot be adjusted for the benefit of a procedure, which is particularly pertinent in emergency and cancer treatments, and they do not take into account quality of life, which is likely to have an important role in the decision being made. Primary chemoradiotherapy is associated with 52 132 micromorts, which is more than that for major head and neck surgery with microvascular reconstruction (10 000 micromorts). The numbers alone may be confusing but they can be effectively communicated graphically (Fig. 1). However, caution is needed when different treatments are compared in this way, as there is the potential for selection bias, for example, when comparing surgery with chemoradiotherapy. Patients undergoing surgery are likely to have been deemed fit enough and to have operable, lower-stage disease. Data on surgical risk have been based on death at 30 days, but some deaths after this time may still have resulted from the surgery. We think that micromorts are a simple measure that can be used to compare risk and make it more understandable. They could be used as an adjunct to inform patients about the risk of an anaesthetic or to evaluate postoperative outcomes,
and could help to explain risk when discussing consent with patients. Conflict of Interest We have no conflicts of interest.
References 1. Lack JA, Rollin AM, Thoms G, et al. Raising the standard: information for patients. London: The Royal College of Anaesthetists; 2003. 2. Ahmed H, Naik G, Willoughby H, et al. Communicating risk. BMJ 2012;344:e3996. 3. Howard R. On making life and death decisions. In: Richard J, Schwing C, Albers WA, editors. Societal risk assessment: how safe is safe enough?. New York: Springer; 1980. p. 89–113. 4. Jenkins K, Baker AB. Consent and anaesthetic risk. Anaesthesia 2003;58:962–84. 5. British Parachute Association. How safe? Available from URL: http://www.bpa.org.uk/staysafe/how-safe/. 6. Bonner JA, Harari PM, Giralt J, et al. Radiotherapy plus cetuximab for squamous-cell carcinoma of the head and neck. N Engl J Med 2006;354:567–78. 7. Cooper JS, Pajak TF, Forastiere AA, et al. Postoperative concurrent radiotherapy and chemotherapy for high-risk squamous-cell carcinoma of the head and neck. N Engl J Med 2004;350:1937–44. 8. Pohlenz P, Klatt J, Schmelzle R, et al. The importance of in-hospital mortality for patients requiring free tissue transfer for head and neck oncology. Br J Oral Maxillofac Surg 2013;51:508–13. 9. Wilkinson KA, Martin IC, Freeth H, et al. On the right trach? A review of the care of patients who underwent a tracheostomy. London: National Confidential Enquiry into Patient Outcome and Death; 2014. 10. Farmah S, Ali Z, Rao J, et al. Survey of mortality rates and consent practices for orthognathic surgery in UK OMFS units. Br J Oral Maxillofac Surg 2013;51:e127. 11. Gabbe BJ, Finch CF, Cameron PA, et al. Incidence of serious injury and death during sport and recreation activities in Victoria, Australia. Br J Sports Med 2005;39:573–7.
British Journal of Oral and Maxillofacial Surgery 54 (2016) 230–231
Short communication
Micromorts - what is the risk? A.M. Fry a,∗ , A. Harrison b , M. Daigneault b a
Department of Oral and Maxillofacial Surgery, Sheffield Teaching Hospitals NHS Foundation Trust, Charles Clifford Dental Hospital, 76 Wellesley Rd, Sheffield, South Yorkshire S10 2SZ b The School of Clinical Dentistry, The University of Sheffield, 76 Wellesley Rd, Sheffield, South Yorkshire S10 2SZ Accepted 20 November 2015 Available online 30 December 2015
Abstract The effective communication of risk, which is central to the process of consent, can be difficult, and can be hard for patients to understand. We introduce the potential utility of the micromort, a unit of risk defined as a one-in-a-million chance of sudden death, which allows clinicians to compare the risks of an intervention with those of different activities, making them easier to understand. © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
Keywords: Mortality; Risk; Oncology; Consent; Micromort
Introduction The effective communication of risk is central to the process of consent, defined by the General Medical Council as good medical practice. Several methods have been used to describe risk - for example, a risk of one in 1000 is termed “uncommon” or is equivalent to “someone in your village”.1 Percentage risks can be difficult for some patients to understand, but whichever method is used, the way in which the information is presented can have a profound effect on the decision made. Many patients find it helpful to have comparators.2 A micromort is a unit defined as a one-in-a-million risk of sudden death.3 A single micromort is roughly the normal daily risk of death from external causes for the general population in Europe, based on figures from the Office for National Statistics in 2012, and it provides a straightforward measure that can be used to compare the risks involved in different activities. A general anaesthetic, for example, has a reported risk of death of around 1 in 100 000
∗
Corresponding author. E-mail address: [email protected] (A.M. Fry).
Table 1 Number of micromorts associated with different interventions and recreational activities. Micromorts Interventions: Primary chemoradiotherapy for squamous cell carcinoma of the head and neck6 Postoperative chemoradiotherapy7 Microvascular reconstruction of the head and neck8 Tracheostomy9 Bimaxillary osteotomy10 Single jaw osteotomy10 General anaesthetic4 Recreational activities: Sky diving5 Fishing11 Rock climbing11 Horse riding11
52 132 17 544 10 000 7576 2300 1600 10 10/jump 92/year 66/year 297/year
(10 micromorts),4 which is the same as that quoted by the British Parachute Association for a single jump by an experienced sky diver.5 Mortality rates for operations and medical treatments can readily be converted into micromorts and used for comparison (Table 1).6–11
http://dx.doi.org/10.1016/j.bjoms.2015.11.023 0266-4356/© 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.
A.M. Fry et al. / British Journal of Oral and Maxillofacial Surgery 54 (2016) 230–231
231
Fig. 1. Graph to show the comparable levels of risk, measured in micromorts, for different interventions.
Discussion Mortality rates quoted for populations in general can be of limited value for individual patients, so risks have been stratified to identify those at greatest risk. With further statistical evaluation it should be possible to allocate micromorts according to personal risk factors and coexisting conditions. A similar approach could also provide a standard means of presenting comparable outcome data for individual surgeons. However, the use of micromorts has limitations. As they are a measure of the risk of death only, the cause of death must be clearly defined, and as many decisions require a tradeoff between harm and benefit,2 they could be misleading if viewed in isolation. They cannot be adjusted for the benefit of a procedure, which is particularly pertinent in emergency and cancer treatments, and they do not take into account quality of life, which is likely to have an important role in the decision being made. Primary chemoradiotherapy is associated with 52 132 micromorts, which is more than that for major head and neck surgery with microvascular reconstruction (10 000 micromorts). The numbers alone may be confusing but they can be effectively communicated graphically (Fig. 1). However, caution is needed when different treatments are compared in this way, as there is the potential for selection bias, for example, when comparing surgery with chemoradiotherapy. Patients undergoing surgery are likely to have been deemed fit enough and to have operable, lower-stage disease. Data on surgical risk have been based on death at 30 days, but some deaths after this time may still have resulted from the surgery. We think that micromorts are a simple measure that can be used to compare risk and make it more understandable. They could be used as an adjunct to inform patients about the risk of an anaesthetic or to evaluate postoperative outcomes,
and could help to explain risk when discussing consent with patients. Conflict of Interest We have no conflicts of interest.
References 1. Lack JA, Rollin AM, Thoms G, et al. Raising the standard: information for patients. London: The Royal College of Anaesthetists; 2003. 2. Ahmed H, Naik G, Willoughby H, et al. Communicating risk. BMJ 2012;344:e3996. 3. Howard R. On making life and death decisions. In: Richard J, Schwing C, Albers WA, editors. Societal risk assessment: how safe is safe enough?. New York: Springer; 1980. p. 89–113. 4. Jenkins K, Baker AB. Consent and anaesthetic risk. Anaesthesia 2003;58:962–84. 5. British Parachute Association. How safe? Available from URL: http://www.bpa.org.uk/staysafe/how-safe/. 6. Bonner JA, Harari PM, Giralt J, et al. Radiotherapy plus cetuximab for squamous-cell carcinoma of the head and neck. N Engl J Med 2006;354:567–78. 7. Cooper JS, Pajak TF, Forastiere AA, et al. Postoperative concurrent radiotherapy and chemotherapy for high-risk squamous-cell carcinoma of the head and neck. N Engl J Med 2004;350:1937–44. 8. Pohlenz P, Klatt J, Schmelzle R, et al. The importance of in-hospital mortality for patients requiring free tissue transfer for head and neck oncology. Br J Oral Maxillofac Surg 2013;51:508–13. 9. Wilkinson KA, Martin IC, Freeth H, et al. On the right trach? A review of the care of patients who underwent a tracheostomy. London: National Confidential Enquiry into Patient Outcome and Death; 2014. 10. Farmah S, Ali Z, Rao J, et al. Survey of mortality rates and consent practices for orthognathic surgery in UK OMFS units. Br J Oral Maxillofac Surg 2013;51:e127. 11. Gabbe BJ, Finch CF, Cameron PA, et al. Incidence of serious injury and death during sport and recreation activities in Victoria, Australia. Br J Sports Med 2005;39:573–7.