approaches to reducing sudden death in the workforce of the oau, ile-ife kayode ijadunola, md, msc,...

Approaches to Reducing Sudden Death in the Workforce

of the OAU, Ile-Ife

Kayode Ijadunola, MD, MSc, FWACPAssociate Professor, Department of Community Health

OAU, October 30, 2013

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An Exercise in Epidemiology?

Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations and the application of study findings to the control of health problems.

So the words to watch are: Distribution – who is affected by sudden death, where,

when, under what circumstances? Determinants – causes, risk factors, associated factors? Specified population – Humans (OAU community) Control – eliminate, reduce the burden, prevent

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An Exercise in Epidemiology?

Although, hazard prevention/risk elimination and reduction is the ultimate goal of Epidemiology and is most desirable, it should be tempered by the recognition that death can only be deferred, but cannot prevented on the long run

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What is Sudden Death? Sudden (cardiac) death [SCD] is typically defined as an

unexpected death in a person with or without pre-existing heart disease, involving an abrupt loss of consciousness due to blood circulatory collapse and occurring within 1 hour of the onset of symptoms

SCD is witnessed in only two-thirds or less of cases, the rest happens when no one is there, making the diagnosis and time of onset difficult to establish

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Global Burden of Sudden Death

In the developed countries, SCD represents the single largest cause of natural death, accounting for 12-18% of the total deaths, and 50% of heart related deaths

Each year in the United States alone, 300,000 people die from (cardiac arrest) heart attacks (range 184,000-462,000); in Canada, deaths number tens of thousands

In recent studies using multiple sources of data in the United States, Netherlands, Ireland, and China, SCD rates ranged from 50 to 100 deaths per 100 000 people in the general population

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The average age of sudden death in Seattle, Washington, and Maastricht, Holland is 66 years and 62 years respectively, and incidence increases with age

Age adjusted death rate figures show that men are 2-4 times more affected compared with women

African-Americans are twice as likely as whites to experience (cardiac arrest) heart attack, and half as likely to survive an event of cardiac arrest

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A survey of sudden death among a working population in Japan revealed an incidence of 22 deaths/100,000 among men and 8 deaths/100,000 among women

The incidence increased with age from 2 deaths/100,000 among men aged 20-24 yrs to 97 deaths/100,000 among men over 60 years

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There are hardly any population based studies of sudden death in the African literature

Two hospital based studies from autopsies in pathology

departments were found, one in South Africa and one in Ile-Ife, Nigeria

The Nigerian study determined among other variables, the circumstances of death and related causal variables in cases of sudden cardiac death among Nigerians

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The records of 2,529 medico-legal autopsies over a ten-year period were reviewed, of which 79 were found to be cases of sudden cardiac deaths (SCD)

The SCD cases consisted of 59 males (74.7%) and 20

females (25.3%), with age ranging from 27 to 80 years

The average age at death was 54 yrs for males and 52 yrs for females

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Hypertensive heart disease was the cause of death in 66 cases (83.5%), of which only 20 (30.3%) were previously diagnosed!

Diseases of the heart vessels and heart muscle of unknown origin ranked next as the most common cause of death with 5 cases (6.3%) each

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A previous study among a working population of Japan, showed that 58% of sudden death was due to diseases of the heart and the blood vessels

30% was due to diseases of the blood vessels of the brain (cerebro-vascular diseases or stroke)

6% was due to diseases of the chest such as pneumonia and asthma

1% was due to bleeding in the food canal (GIT) 1% was due to epilepsy

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Despite the large numbers of SCDs in the general population, the overall incidence is only 0.1% per year. That is any population-based preventive measure would have to be applied to 1000 people to prevent one sudden death!

Therefore, to reduce the incidence of SCD, we must -either accurately identify those at risk; or

-develop safe, low-cost interventions that can be applied to the population at large

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Risk factors: Individual and Population

The critical challenge for scientific and clinical investigators of SCD is that the patient group contributing the highest deaths is comprised not of individuals who are at risk due to a prior sudden heart related disease or those with some other identified disease processes (in whom the estimated one-year risk reaches 30% or greater);

Rather, the group contributing the highest number of sudden deaths is the general population with an estimated risk of only 1-2/1000 people!

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Fig. 1. Incidence of sudden cardiac death in specific populations and annual sudden

cardiac death numbers

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SCD is the first manifestation of disease in almost 50% of patients with heart blood vessel (coronary artery) disease

For example, in the Quebec Cardiovascular Study, 42% of all heart vessel disease deaths in men fulfilled the criteria for sudden death or were in individuals found dead in bed

Approximately 55% of male and 63% of female SCD victims have no previous history of heart disease, and therefore SCD is often the initial manifestation of heart disease

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Risk factors: Individual and Population Information from trials of patients put on continuous

monitors showed that only approximately 1 in 3 sudden deaths occurs in patients with known risk factors (markers).

That the majority of sudden cardiac deaths occur in individuals who have not been identified as being at high risk necessitates new measures and modalities for recognizing predisposition and stratifying risk

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The most powerful predictor of sudden cardiac death is disease on the left side of the heart (poor left ventricular function) .

Other risk factors are similar to the risk factors for heart vessel (coronary) disease which are well known

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Public health efforts to significantly reduce mortality from SCD through identification of persons at risk face numerous challenges

First, the incidence of SCD in the population is low, even in common high risk clinical populations

Second, the current risk factors have low positive

predictive value (i.e. most of the patients with the risk factors will not experience sudden death in a particular year)

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Risk factors: Individual and Population The risk factors also have low sensitivity (many victims

of SCD do not have the particular risk factor)

Therefore, the use of the currently identified risk factors to characterize high risk groups comes at the cost of (decreasing sensitivity) i.e. overlooking large numbers of SCD victims

A number of additional (complex) factors are currently being explored for their potential in identifying individuals at risk

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The clarification of genetic risk is critical; studies are revealing that SCD tends to aggregate in families

It is becoming increasingly clear, for instance, that genetic factors may play a role in the development of the heart muscle disease that is associated with SCD

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Evidence from epidemiologic studies, animal experiments and clinical research implicates a part of the nervous system (autonomic) in the cause of SCD

Emotional stress and vigorous physical exertion may be important triggers for SCD

There also appears to be a (circadian) pattern to the timing of SCD, with significantly more events occurring in the morning (6am through 12 noon), perhaps due to increased autonomic nervous system activity

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Strategies to decrease mortality from SCD

Strategies to decrease the burden of SCD must aim at both reduction in event rate and improvement in event survival

First are the primary preventive measures in the general population targeting reductions in known heart and blood vessel (cardiovascular) risk factors and risk factors for stroke

Because of the low incidence of SCD in the general population, these interventions will have to be broad- based, safe, easily administered, acceptable to the population and inexpensive

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Strategies to decrease mortality from SCD Second is primary prevention of SCD in patients with

known heart disease with a focus on drug therapies

Many of the traditional risk factors associated with the development of heart vessel (coronary) disease are also associated with SCD; clinical and public health efforts that promote effective treatment of these risk factors are likely to reduce the incidence of out-of-hospital cardiac arrest in the general population

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Strategies to decrease mortality from SCD Eating right is key. The consumption of at least one fatty

fish meal per week is associated with a 48% reduction in the risk of SCD; avoid animal fat as much as possible!

Given the observation that the risk of cardiac arrest is particularly large among current smokers, and declines rapidly after stopping smoking, smoking cessation will likely impact a reduction in the risk of SCD

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Strategies to decrease mortality from SCD Regular exercise is associated with an overall reduction

in the risk of SCD; some exercise is better than none, regardless of the intensity, but there is a transient increase in risk during strenuous exercise

In the physicians health study, men who had two to four drinks of alcohol per week had a significantly reduced risk for SCD, compared to men who never drank, but heavy alcohol consumption (six or more drinks per day) or binge drinking increased the risk of SCD

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You must check your blood and BP numbers (parameters) at intervals, especially once you are 40 years and above

BP monthly, if you are hypertensive, and at least yearly if you are not, especially if there is family history

Blood sugar at least yearly if not diabetic, and daily if diabetic using home based measures

Blood cholesterol profile at least yearly

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Will benefit from other specialized tests that might reveal the status of other organs periodically, if over 40 years

Pap’s smear for women yearly if no abnormal tests; more frequently if tests are abnormal

Self breast examination, clinical breast examination and mammography as indicated

Blood urea nirtogen and creatinine for the kidneys Rectal examination and Prostate Specific Antigen

periodically for men over 40 years

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Strategies to decrease mortality from SCD Pharmacological treatment of patients with known heart

disease and processes for improving event survival is the business of the physicians

However, they must receive the cooperation of the patients who must come to the hospital, accept to be treated, adhere to drug therapy, and follow-up on treatment

The hospitals must also be sufficiently equipped with staff and necessary infrastructure to respond to emergencies (the health center specifically here)

There must also be a critical mass of trained paramedics who can respond in little or no time to emergencies at the community level

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Prognosis

For patients who suffer out-of-hospital cardiac arrest due to heart disease, survival rates are low, even in the setting of witnessed arrests

Long-term survival rates of 20% have been reported from urban centers with the ability to provide rapid-response and defribillator-equipped emergency services

However, national averages of successful resuscitation from out-of-hospital cardiac arrest due to heart disease are much lower (1-2%)

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References Deo R, Albert CM. Epidemiology and Genetics of Sudden Cardiac

Death. Circulation. 2012; 125: 620-637 doi: 10.1161/ CIRCULATIONAHA.111.023838

Tiemensma M, Burger EH. Sudden and unexpected deaths in an adult population, Cape Town, South Africa, 2001-2005.S Afr Med J. 2012 Jan 27;102(2):90-4

Rotimi O, Fatusi AO, Odesanmi WO. Sudden cardiac death in Nigerians--the Ile-Ife experience.West Afr J Med. 2004 Jan-Mar;23(1):27-31

Zipes DP. Epidemiology and mechanism of sudden cardiac death. Can J Cardiol; 21(Suppl A): 37A-40A

Sotoodehniaa N, Zivina A, Bardya GH, Siscovick DS. Reducing mortality from sudden cardiac death in the community: lessons from epidemiology and clinical applications research. Cardiovascular Research 2001; 50: 197–209

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Thank you!

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approaches to reducing sudden death in the workforce of the oau, ile-ife kayode ijadunola, md, msc,...

Documents

studies of sudden death

survey of sudden death

global burden of sudden

sudden cardiac death

circumstances of death

cases of sudden cardiac

unexpected death

average age of sudden