Sudden death in persons younger than 40 years of age: incidence and causes

Characterizing sudden death and dead-in-bed syndrome in Type 1 diabetes: analysis from two childhood-onset Type 1 diabetes registries

AIMS

Type 1 diabetes mellitus increases the risk for sudden unexplained death, generating concern that diabetes processes and/or treatments underlie these deaths. Young (< 50 years) and otherwise healthy patients who are found dead in bed have been classified as experiencing 'dead-in-bed' syndrome.

METHODS

We thus identified all unwitnessed deaths in two related registries (the Children's Hospital of Pittsburgh and Allegheny County) yielding 1319 persons with childhood-onset (age < 18 years) Type 1 diabetes diagnosed between 1965 and 1979. Cause of death was determined by a Mortality Classification Committee (MCC) of at least two physician epidemiologists, based on the death certificate and additional records surrounding the death.

RESULTS

Of the 329 participants who had died, the Mortality Classification Committee has so far reviewed and assigned a final cause of death to 255 (78%). Nineteen (8%) of these were sudden unexplained deaths (13 male) and seven met dead-in-bed criteria. The Mortality Classification Committee adjudicated cause of death in the seven dead-in-bed persons as: diabetic coma (n =4), unknown (n=2) and cardiomyopathy (n=1, found on autopsy). The three dead-in-bed individuals who participated in a clinical study had higher HbA(1c) , lower BMI and higher daily insulin dose compared with both those dying from other causes and those surviving.

CONCLUSIONS

Sudden unexplained death in Type 1 diabetes seems to be increased 10-fold and associated with male sex, while dead-in-bed individuals have a high HbA(1c) and insulin dose and low BMI. Although sample size is too small for definitive conclusions, these results suggest specific sex and metabolic factors predispose to sudden unexplained death and dead-in-bed death.

Strategy for clinical evaluation and screening of sudden cardiac death relatives

Sudden cardiac death (SCD) may be the first and final manifestation of several heart diseases. In the young, SCD is often caused by a hereditary cardiac disease. As the most frequently seen inherited cardiac diseases have an autosomal-dominant pattern of inheritance, half of the first-degree relatives are at risk of having or developing the same disease. Therefore, screening of these high-risk relatives is a rational approach to reduce the incidence of SCD. To offer family screening and counseling, the cause of death should be carefully established. Autopsy is only performed in a limited number of cases. We advocate for systematic autopsies in SCD, because positive findings are crucial for choosing the optimal screening program for the relatives. A negative autopsy makes identification of at-risk population difficult. However, this finding also provides clues to the cardiologist, because a limited number of inherited cardiac diseases associated with SCD are without any structural changes. In other cases, the autopsy may reveal noncardiac causes of death, which is also important for reassuring the relatives. However, in cases with no autopsy or negative findings, thorough clinical examinations and selective genetic screening of relatives may identify a likely diagnosis in more than 50% of affected families. There is a need for consensus regarding routine evaluation of SCD cases and the ethical and legal framework related to postmortem testing. We propose an algorithm that narrows the diagnostic possibilities in apparently healthy relatives of young SCD victims. Molecular autopsy may play an important role.

Nationwide study of sudden cardiac death in persons aged 1-35 years

AIMS

The aim of this investigation was to study the incidence of sudden cardiac death (SCD) in persons aged 1-35 years in a nationwide setting (5.38 million people) by systematic evaluation of all deaths.

METHODS AND RESULTS

All deaths in persons aged 1-35 years in Denmark in 2000-06 were included. Death certificates were read independently by two physicians. The National Patient Registry was used to retrieve information on prior medical history. All autopsy reports were read and the cause of death was revised based on autopsy findings. We identified 625 cases of sudden unexpected death (10% of all deaths), of which 156 (25%) were not autopsied. Of the 469 autopsied cases, 314 (67%) were SCD. The most common cardiac cause of death was ischaemic heart disease (13%); 29% of autopsied sudden unexpected death cases were unexplained. In 45% of SCD cases, the death was witnessed; 34% died during sleep; 89% were out-of-hospital deaths. Highest possible incidence rate of SCD in the young was 2.8 per 100 000 person-years including non-autopsied cases of sudden unexpected death. Excluding those, the incidence rate declined to 1.9 per 100 000 person-years.

CONCLUSIONS

A total of 7% of all deaths in the young can be attributed to SCD, when including non-autopsied cases (autopsy ratio 75%). The incidence rate of SCD in the young of 2.8 per 100 000 person-years is higher than previously reported.

Rationale and design of the CAREFUL study : The yield of CARdiogenetic scrEening in First degree relatives of sudden cardiac and UnexpLained death victims <45 years

Background. Sudden cardiac death (SCD) in the young (1-45 years) is a strong risk factor for the presence of inherited cardiac diseases in surviving first-degree relatives. Postmortem investigation of the victim and cardiogenetic evaluation of the first-degree relatives is indicated to detect inherited cardiac diseases and treat relatives at an early stage to prevent SCD. In the Netherlands, postmortem investigation is often not performed and relatives of SCD and sudden unexplained death (SUD) victims are rarely evaluated for inherited cardiac diseases.Methods. A prospective population-based follow-up study carried out in two intervention regions and two control regions. In the intervention regions a comprehensive intervention (stimulate autopsy and storage of victims DNA and the referral of first-degree relatives for cardiogenetic evaluation) is applied in a 'top down' and 'bottom up' mode. In each region, young sudden death victims are registered and for all cases performance of autopsy and evaluation of relatives in a cardiogenetics outpatient clinic will be determined.Expected results. The study will provide information on the incidence of sudden death in the young and the proportion of diagnosed inherited cardiac diseases. Moreover, the additional value of the introduction of two different preventive strategies directed at early detection of inherited cardiac diseases in first-degree relatives to usual care will be evaluated. Conclusion. The CAREFUL study will help to set a new standard of care in the evaluation of young sudden death victims and their relatives to identify the presence of inherited cardiac diseases, in order to prevent sudden death. (Neth Heart J 2010;18:286-90.).