Autopsy Analysis of Sudden Deaths in Adults:

Causes and Demographics from a One-Year Prospective Study

Authors: JAYESHKUMAR KANANI

Abstract

Introduction: Sudden death, defined as death occurring suddenly or within 24 hours of the onset of terminal symptoms without known trauma, poisoning, or violent asphyxia, remains a significant concern. This study aims to review autopsy findings in sudden death cases, identify common causes, and explore emerging trends. Methods: This one-year cross-sectional, randomized, prospective study included cases of sudden, unexpected deaths of individuals over 18 years old who were brought for medico-legal autopsies. Exclusion criteria were cases involving trauma, intoxication, poisoning, and violent deaths. Results: Out of 464 autopsies performed, 146 cases (31%) were sudden death cases. The majority were older adults (46.6%), with a significant male predominance (83.6%). Cardiovascular diseases were the leading causes of death, with coronary artery disease (45.8%) and acute myocardial infarction (35.6%) being the most common. Pulmonary edema and pneumonia were significant respiratory causes of death, each accounting for 25.4% and 18.4% respectively. Obesity analysis revealed that 18.4% of the cases were obese, with ischemic heart disease being the predominant cause of death among obese individuals. Other causes included septicemia, pulmonary embolism, intracranial hemorrhage, typhoid, and malignancies. Conclusion: The study provides valuable insights into the causes of sudden, unexpected deaths, highlighting the significant impact of cardiovascular diseases, demographic factors, and obesity. The findings call for targeted public health interventions, enhanced awareness, early diagnosis, and timely management of chronic conditions to reduce the incidence of sudden deaths.

Introduction

Sudden death refers to an unexpected fatality that takes place abruptly or within 24 hours after the appearance of final symptoms without any known trauma, poisoning, or violent asphyxia [1].

Different organizations and experts describe sudden death in slightly different ways, depending on their criteria and practice standards.

According to the World Health Organization (WHO), sudden death is a fatal event occurring within 24 hours of the initial onset of symptoms. [2].

This term may also include deaths that occur abruptly, lack clinical explanation, or remain obscure despite no unnatural elements are involved in their causation.

Despite advances in medicine, diagnostic tools often lack the accuracy to determine the discrepancy that may exist between clinical impressions and definitive autopsy results [3].

A characteristic feature of sudden natural death is its rapid occurrence in apparently healthy individuals, frequently outside the hospital and unnoticed by anyone, thus preventing any clinical intervention to save the person's life. The absence of observed ante-mortem symptoms and circumstances surrounding the death often raises suspicions about the cause and manner of death.

The primary goal of an autopsy is to identify the definitive diagnosis and clarify the most likely underlying cause of death. Autopsies also provide essential data for public health and preventive strategies. The occurrence of sudden death poses a significant challenge to general autopsy pathologists. In cases where the deceased was covered by an insurance policy, an autopsy is highly indicated. Medical officers should refrain from issuing death certificates particularly in situations involving unexpected fatalities without conducting an autopsy. Given the sudden nature of these deaths, doctors should report such cases to legal authorities for necessary investigation [4].

Sudden deaths are estimated to contribute to nearly one-tenth of all global mortality.

Cardiovascular conditions contribute to roughly 45-50%, respiratory disorders to 15-23%, neurological illnesses to 10-18%, alimentary system diseases to 6-8%, genito-urinary system diseases to 3-5%, and 5-10% are due to miscellaneous causes [1, 5].

Studies indicate that in many developed nations, undiagnosed ischemic heart disease represents the leading contributor to sudden cardiac mortality [6, 7].

This study aims to systematically review autopsy findings in cases of sudden death, identify common cause of death, and explore emerging trends in causation. By doing so, we seek to enhance the understanding of sudden death, contribute to forensic knowledge, and ultimately improve outcomes through early detection and prevention. Furthermore, this study seeks to evaluate the sociodemographic characteristics associated with sudden natural deaths.

Materials and Methods

This one-year prospective observational investigation was carried out in the Department of Forensic Medicine and Toxicology at a tertiary care medical center in Surat from April 2023 to April 2024.

The research included all cases of individuals over 18 years of age who died suddenly and/or unexpectedly before reaching the hospital and were brought in for medico-legal autopsy.

Cases involving hospital admissions where death occurred within 24 hours of the onset of symptoms of an underlying natural disease, with no history of injury, poisoning, terminal, or chronic illness, and subsequently referred for medico-legal autopsy, were also included.

Exclusion criteria encompassed patients with trauma, intoxication, poisoning, and violent deaths. Cases with insufficient clinical information or those exhibiting decomposition were excluded from analysis. Deaths in individuals with a cachexic body and visible chronic lung or liver pathology were also excluded.

Furthermore, cases where the deceased was already suffering from a disease and the cause of death was attributed to or resulted from that pre-existing condition were excluded from the study.

Prior to starting the post-mortem examination, detailed histories were obtained from relatives, including details on symptom onset and duration, personal habits, family and medical history, and available treatment documentation. For hospitalized patients, medical records were reviewed to note the provisional diagnosis and the exact timing at which terminal symptoms began.

Comprehensive external and internal autopsy examinations were performed and carefully documented. Gross findings of tissues were noted, and tissue samples were preserved in 10% formal saline. Tissue samples of 3-5mm thickness were prepared for rapid and effective fixation, stained with Haematoxylin and Eosin, and examined for histopathological analysis.

Suspected poisoning cases underwent further investigation through chemical analysis to rule out poisoning. Individuals were classified into age categories using predefined Young Adults (18-30 years), Middle-aged Adults (31-45 years), and Older Adults (>45 years).

Additionally, each case was categorized into obesity classifications according to the World Health Organization (WHO) BMI guidelines. The classifications are as

Underweight: BMI less than 18.5

Normal BMI 18.5 to 24.9

Overweight: BMI 25 to 29.9

Obesity (Class 1): BMI 30 to 34.9

Obesity (Class 2): BMI 35 to 39.9

Obesity (Class 3): BMI 40 or greater

After completing the thorough post-mortem examination, histopathological study, and chemical analysis, an opinion on the cause of death was formulated. Demographic information and final autopsy diagnoses were compiled in Excel. Data analysis was performed using SAS 9.4.

Descriptive statistical analysis was performed with results expressed as counts and percentages.

Categorical variables were compared using the chi-square test. For each disease category, a group-level chi-square test was used to assess differences across all subgroups.

Individual p-values were obtained through pairwise chi-square comparisons using the reference category.

Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to quantify the strength of association between age/BMI groups and outcomes. Statistical significance was set at p <0.05.

Results

During the one-year study period, upon applying the exclusion criteria, 146 cases (31%) out of 464 were deemed suitable for inclusion in this study.

The demographic characteristics of the study population (Table 1) revealed that the largest group consisted of older adults, accounting for 46.6% (68 cases). This was followed by middle-aged adults, who made up 37.6% (55 cases), and young adults, comprising 15.8% (23 cases).

This distribution highlights a significant prevalence of sudden death occurrences among older individuals.

Regarding marital status, a substantial majority of the cases were married, representing 95.8% (140 cases). Unmarried individuals constituted only 4.2% (6 cases), suggesting a higher incidence of sudden death among married individuals in this sample.

In terms of sex distribution, males were overwhelmingly predominant, accounting for 83.6% (122 cases), whereas females comprised 16.4% (24 cases). This significant gender disparity indicates a higher occurrence of sudden deaths among men.

Examining the obesity categories (Table 2), most individuals were of normal weight, comprising 50.6% (74 cases).

Overweight individuals accounted for 29.4% (43 cases), and those classified under obesity were categorized into three Class 1 obesity was observed in 9.6% (14 cases), Class 2 in 7.6% (11 cases), and Class 3 in 1.4% (2 cases).

There were also a small number of underweight individuals, making up 1.4% (2 cases).

The analysis of the causes of death (Table 3) revealed that coronary artery disease emerged as the predominant cause, responsible for 45.8% (67 cases) of the deaths.

Acute myocardial infarction (Figure 1A) followed closely, accounting for 35.6% (52 cases).

Other significant causes included pulmonary edema (Figure 1B), chronic liver disease (Figure 1C), and chronic kidney disease (Figure 1D), each contributing to 25.4% (37 cases) of the deaths.

Pneumonia was identified in 18.4% (27 cases), while chronic lung disease was noted in 6.2% (9 cases).

An additional 11.6% (17 cases) of deaths were due to other causes such as septicemia, pulmonary embolism, typhoid, intracranial hemorrhage, and malignancy.

When broken down by age groups (Table 4), ischemic heart disease constituted the most frequently identified cause of death, especially among older adults (26%, 38 cases), followed by middle-aged adults (16.4%, 24 cases).

Although young adults had fewer overall cases, pulmonary edema (6.8%) and chronic liver disease (5.4%) were relatively more common within this group.

Acute myocardial infarction was significantly more prevalent in older adults (19.9%) compared to middle-aged (11.6%) and young adults (4.1%), showing statistical significance (p=0.2167).

Pulmonary edema was more commonly seen in middle-aged adults, while its incidence was significantly lower among older adults (p=0.0017).

Other causes such as chronic kidney disease, pneumonia, and chronic liver disease were more evenly distributed across the age groups with no statistically significant differences.

The obesity-specific analysis (Table 5) demonstrated that ischemic heart disease continued to be the major contributor to mortality across all BMI categories, with the highest proportion in normal weight individuals (24.6%, 36 cases).

Myocardial infarction showed slightly higher odds among overweight and obese individuals compared to normal weight with statistical significance (group p=0.0138).

Causes such as chronic liver disease, pneumonia, and pulmonary edema also occurred across all weight groups without significant variation.

Overall, no strong statistical association was found between obesity category and specific cause of death, though trends suggest a potential higher risk of myocardial infarction in obese individuals.

In summary, ischemic heart disease stands out as the predominant cause of sudden death, especially among older adults and individuals across various obesity categories.

These findings emphasize the urgent need for enhanced preventive measures and targeted interventions to address cardiovascular health and reduce the incidence of sudden deaths in the population.

Discussion

In this study, sudden fatalities accounts for the 31% of total autopsies performed in one year duration. Sex distribution showed a significant male predominance (83.6%), aligning with global data suggesting that males are more susceptible to sudden death events than females [8, 9, 10].

In this study, cardiovascular disorders predominated, particularly coronary artery disease and acute myocardial infarction together accounting for the majority of cases (45.8% and 35.6%, respectively). These results are consistent with the well-documented role of ischemic heart disease continues to be the main cause of sudden cardiac mortality across both developed and developing regions [10, 11, 12, 13, 14].

The age-specific analysis of causes of death revealed that ischemic heart disease was the most prevalent across all age groups, particularly among older adults. This finding highlights the cumulative effect of aging on cardiovascular health and the critical need for early intervention and management of heart disease risk factors.

Pulmonary edema and pneumonia were the predominant common mortality of death in respiratory system and accounts for 25.4% and 18.4% respectively. This results align with the previous research [13, 14].

Among young adults, pulmonary edema and chronic liver disease were more prominent, suggesting different underlying health dynamics in this age group. This study showed that 18.4% of the cases were obese, and these findings are consistent with previous studies [15].

Obesity-specific analysis indicated that ischemic heart disease represented the primary cause of death among obese individuals showing the strong association between obesity and cardiovascular risk. These findings highlight the need to manage obesity as a major public health concern to reduce the risk of sudden fatalities.

Other causes of death included septicemia, pulmonary embolism, intracranial hemorrhage, typhoid, malignancies, and other conditions.

Understanding the etiology of sudden death is paramount for several reasons. Firstly, it aids in the identification of potential risk factors, enabling healthcare providers to develop targeted interventions and surveillance programs.

Secondly, it informs public health policies aimed at reducing the incidence of such deaths. Lastly, it fosters advancements in medical and forensic sciences, driving innovation in diagnostic and therapeutic approaches.

This research offers important perspectives on the underlying causes of sudden deaths, unexpected deaths, highlighting the predominant role of cardiovascular diseases and the significant impact of demographic and obesity factors.

The findings call for targeted public health interventions aimed at preventing cardiovascular diseases, managing obesity, and improving overall health outcomes to reduce the incidence of sudden deaths.

Enhanced awareness, early diagnosis, and timely management of chronic conditions are essential strategies in mitigating the risks associated with sudden, unexpected deaths.

Limitations

There are certain limitations to this study that warrant consideration. First, due to the medico-legal nature of the data collection, personal habits such as smoking, alcohol consumption, and substance use could not be reliably obtained.

Family medical history and socioeconomic details were also unavailable, as relatives were often reluctant to share sensitive information during the grief period, and such inquiries are not routinely made during medico-legal autopsies.

Second, while chronic illnesses such as liver, lung, and kidney diseases were included when they coexisted with other potential contributing factors, cases where a known chronic disease was clearly the direct and sole cause of death were excluded.

This exclusion was done to maintain the study's focus on sudden and unexpected deaths, rather than those with well-established, ongoing disease trajectories.

However, this approach may limit the generalizability of findings regarding the role of chronic illnesses in sudden death.

Third, the study data were derived exclusively from medico-legal autopsy cases, which may introduce selection bias and may not reflect the full spectrum of sudden deaths occurring in the general population.

Individuals dying in non-suspicious circumstances or without postmortem examinations may have different characteristics that were not captured in this analysis.

Finally, advanced statistical models such as multivariate regression and Bayesian analyses were limited by the availability and granularity of recorded variables.

Future prospective studies with broader data capture, including lifestyle factors and genetic predispositions, could yield a deeper and more complete understanding of sudden adult death patterns.

Conclusions

This work presents a detailed evaluation of the various causes associated with sudden death, unexpected deaths over a one-year period, highlighting the significant impact of cardiovascular diseases, demographic factors, and obesity on mortality rates. With sudden deaths accounting for 31% of the total autopsies performed, the findings emphasize the critical need for targeted public health interventions.

Addressing cardiovascular health, managing obesity, and improving overall health outcomes are essential strategies for reducing the incidence of sudden, unexpected deaths. Enhanced public awareness, focused healthcare interventions, and continuous research are vital in mitigating the risks and preventing the occurrence of sudden deaths in the population.

Conflict of interests

The authors declare no competing interests.