Disease%20Informatics:%20The%20burden%20of%20disease

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Disease Informatics The burden of disease

• R. P. Deolankar

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Welcome to the series of lectures on Disease
Informatics

• Disappointment by research bodies to solve the
  real disease problem is because of not having
  perception of disease complexities
• Diseases have been defined in a simple manner
  leaving several targets for combating disease
  unattended
• IT applications simplify complexities and could
  provide better definition of diseases
• Informatics professionals need to be facilitated
  for development of software for disease study
  using standard guidelines

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Clean bowled is not the complete cricket

• Clean bowled Current one cause one effect --
  disease definition permits dismissal of the
  batsman (say viral disease) only by the ball
  bowled by the bowler hitting the wicket (say
  virus the component cause of the disease that is
  considered as the complete cause)
• Out The treatments given by family physician
  based on his clinical diagnosis also permit the
  dismissal of batsman if the ball hit by the
  batsman is caught, by lbw, run out, stumped etc
  (described as targeting super-component in later
  slides)
• Logic To win the game team must be balanced.
  Team of only bowlers, only batsman, only wicket
  keepers, only captains or only umpires is a joke

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Prerequisite for this lecture

• Lecture no. 25371 DIG for Disease Informatics
  Group. Part I
• Lecture no. 25381 DIG for Disease Informatics
  Group. Part II
• Lecture no. 28921 Disease Informatics Host
  factors simplified
• Lecture no. 30331 Disease Informatics Phytates
  driving from the back-end to Influenza,
  Encephalitis, Hepatitis, Anemia at the front-end.
• Lecture no. 31981 Disease Informatics ICD-11 at
  the doorstep
• Lecture no. 34011 Disease Informatics Terms and
  Jargon to begin with
• Lecture no. 34141 Disease Informatics Brush up
  the terms describing techniques and resources

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Importance of Family Physician

• Draws a mental picture of Disease Causal Chain
  (DiCC) of a patient by
• Recording clinical history, performing clinical
  check up and treating individual
• Predicting disease that could occur in future and
  planning prevention of further disease or
  complication
• Keeping confidential the diagnostic information
  of a particular patient

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Public Health professional

• Focuses on community health protection and
  improvement
• Has to define disease broadly and openly
• Disease definitions should fit to population and
  environment rather than individual
• Subject matter of Epidemiology is covered under
  Public Health

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Epidemiology and public health

• Epidemiologist is an investigator
• Investigates Disease Causal Chains of patients
  drawn by family physicians (clinicians) to arrive
  at accord and discord of the disease continuum
• Studies associations and establishes relationship
  of risk factors of diseases
• On the basis, tries to find out component causes
  and sufficient causes of the diseases

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Genuine epidemiologist interacts with Family
physicians (clinicians)

• Genuine Epidemiologist keeps rapport with
  Clinicians to share inferences drawn from cases
  and try to understand chain of events of diseases
• Epidemiologist share risk factor information and
  elaborates which factors drive the disease from
  backend to frontend
• This interaction permits drawing of hypothetical
  cause and effect diagrams to be verified by
  performing experiments

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Disease informatics

• Disease Informatics is the application of
  Information Science in defining the diseases with
  least error, identifying most of the targets to
  combat a cluster of diseases (Disease Causal
  Chain) and designing a holistic solution (Health
  strategy) to the problem.
• Researchers, Health workers, Clinicians,
  Epidemiologists and Public Health personnel
  benefit from and contribute to the Disease
  Informatics

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The first logical step of disease investigation
know the remarkable events

• Standard terminology can be used by Setting aside
  the combination terms (anatomical
  physiopathological) from MeSH database of NCBI to
  provide the database for events occurring in the
  Disease Causal Chains
• Identify most of the targets to combat a cluster
  of diseases in a command area
• Achieve this by horizontally studying the
  clinical histories of sample cases or by
  identifying the clinically remarkable events in a
  cross section of the community

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The second step sequence the events

• It needs to be known the sequence in which events
  occur
• It is also of the interest to know which factors
  drive the disease processes from the backend
  events to the frontend events
• Make cause and effect diagrams (fish bone)
• The causal factor components could be pooled in a
  pie diagram to explain various sufficient causes
  of the diseases

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What is a case? (In simple words)

• Case is a person, case represents some
  characteristics useful in the investigation
• Normal case Normal person
• Disease case A person showing features of a
  disease
• Non-case A person not showing features of a
  disease

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Case for a Public health study

• Study subjects in a Public Health Study are cases
• Might comprises at-least two types of cases
  Normal cases Disease cases
• The normal case is likely to be defined by the
  investigator
• The disease case (deviation from normal) goes
  naturally

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Inclusion and exclusion criteria

• Which cases are to be included in the study?
• There are criteria that must be met by the cases
  for inclusion in the study
• Which case is to be excluded?
• The cases that would be considered as non-cases
  by a certain criteria

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Case definition

• Case definition of a disease is a description of
  diagnostic criteria of the disease
• Sometimes required in public health study
• Disease in an individual case is
• Disease defined by the case definition
  something more

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Disease continuum

• How to infer the disease if certain persons show
  immunodeficiency syndrome like AIDS without being
  HIVve?
• Generally speaking, Continuum case definition
  something more. Continuum is a whole covers
  cases sometimes not conforming to the standard
  case definition.
• Let us call this set of something more as a
  super-component X (that covers component causes
  of the disease not covered in the case
  definition)
• Components within super-component-X might vary
  from an individual to individual

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Solution to the disease through Super-component X

• It is thought that chicken soup has no antiviral
  factor but has natural healing powers for the
  common cold!!! Does it modulate super-component-X
• Several nutraceuticals and functional foods work
  in this manner and are broad based treatments
• Disease definition for a disease of an Individual
  ? Disease definition prepared for public health
  purpose

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Ayurveda, Siddha, Unani, Yoga and
super-component-X

• The Ancient Indian Medicine provides pre-seasonal
  treatments (shodhan) to uproot seasonal
  infections and diseases rather than performing
  pruning operation on several diseases at the
  front end during season
• Unlike antiviral Oseltamivir, age-old medicines
  (like Tribhuvan Kirti) tackling non-viral
  component causes provide relief in several
  patients having Flu and Cold
• Daily routine (Dinacharya) and seasonal lifestyle
  (Ritucharya) recommended in old days to prevent
  diseases could be redefined to suit modern life

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T1 ? T2 and also CD1 ? CD2

• Patient (P1) reports relief from a viral disease
  (D1 laboratory diagnosis provided by the
  super-specialist virologist) through a treatment
  (T1) given by family physician of P1 on the basis
  of the clinical diagnosis (CD1)
• Patient (P2) exhibiting the disease D1 given T1
  by the associate physician of the virologist
  fails to respond
• P2 then also finds relief by another treatment
  (T2) given by his family physician on the basis
  of his clinical diagnosis (CD2) why?

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Treatment of an individual depends on more
elaborate definition of the disease

• Treatment of viral encephalitis using hormones in
  a case when hormone deficiency is not part of the
  case definition
• Treatment of viral diarrhea using enkephalinase
  inhibitor in a case when enkephalin deficiency is
  not part of the case definition
• Treatment of constipation using prebiotics in a
  case when dysbiosis is not part of the case
  definition

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Grades of disease definition

• Usually case definition describes what is normal,
  suspected, strongly suspected, probable and
  laboratory confirmed case
• This description vary from study to study by
  having or not having certain component causes and
  also description of the severity of the disease

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Effect modification

• The odds ratio between cigarette smoking and lung
  cancer may be smaller among individuals who
  consume large quantities of beta carotene in
  their food when compared to the analogous odds
  ratio among persons who consume little or no beta
  carotene in their food this modification could
  be in an additive manner

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Multiplicative interaction

• Poverty (represented by under-nutrition, unsafe
  water and sanitation, and use of solid fuels are
  more common among poor rural households in
  developing countries) might interact with
  infectious etiology in a multiplicative manner
  represents statistical interaction
• Mortality attributed to the rotavirus
  gastroenteritis is largely seen in developing
  countries rather than developed countries
• Under-nutrition is the single leading global
  cause of health loss

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Complex of risk factors

• Zinc deficiency affects mortality from diarrhea
  directly
• It also affects mortality by reducing growth
• It may also be correlated with underweight, other
  micronutrient deficiencies, and unsafe water and
  sanitation
• This might be a combination of effect
  modification (additive effects) as well as
  statistical interaction (multiplicative)

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What is burden?

• Burden is load or taxing on individual or family
  or society or Nation or the globe
• It could be cultural, chemical, pathological,
  economic, social or socioeconomic
• Disease burden is judged against disease events
• Disease burden could be due to factors driving
  from backend to frontend event of a Disease
  Causal Chain
• Disease investigator needs to understand variety
  of burdens

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Utility of estimating Disease Burden

• Important input to health decision-making and
  planning processes
• Provides a framework for integrating, validating,
  analyzing and disseminating information needed to
  assess the comparative importance of diseases,
  injuries and risk factors in causing premature
  death, loss of health and disability in different
  populations

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Body burden

• Body burden is the load of foreign chemicals in
  the body
• Most of the chemicals could be toxic
• Some of these chemicals could alter the functions
  of genes
• Some of these could disrupt endocrine system

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Burden of disease Measurement of load or taxing
due to disease in a population
Prof. Christopher J. L. Murray
Prof. Alan D Lopez
Dr. Colin D. Mathers
Prof. Dean T. Jamison
Dr. Majid Ezzati
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Burden of disease

• Unit of measurement for Burden of disease DALY
• DALY means Disability-Adjusted Live Year
• Unit of measurement of benefits from intervention
  QALY
• QALY means Quality-Adjusted Life years

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Disease

• Health is compromised due to diseases
• Diseases lead to death and / or disability
• Quality and quantity of life is reduced due to
  disease
• Mortality Disability is proportional to the
  quantity of disease

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Disability

• Disability
• Shortfall in an ideal health status
• an ideal health status actual health status

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DALY

• DALY
• Life lost due to premature mortality
• Years of life lost due to time lived in states
  of less than full health
• One DALY One lost year of "healthy" life

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DALYs across the population

• Sum of these DALYs across the population Burden
  of disease
• Top health Least burden of disease
• Least burden of disease ? living to an advanced
  age, free of disease and disability

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YLL

• Years of Life Lost due to premature mortality in
  the population
• YLL N L
• Where
• YLL Years of Life Lost due to premature
  mortality in the population
• N number of deaths
• L standard life expectancy at age of death in
  years

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Severity of the disease

• Severity of the disease is to be scaled
• Scale for weight factor for severity of disease
  is
• From 0 to 1
• 0 implies perfect health
• 1 implies death

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Disease definition

• Disease is usually defined by
• case definition that depends on
• Causation
• The disability weight
• The population incidence and
• Prevalence

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YLD

• The Years Lost due to Disability (YLD)
• YLD I DW L
• where
• I number of incident cases
• DW disability weight
• L average duration of the case until remission
  or death (years)

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Disease mechanism

• YLD is estimated by cause
• For a particular disease there are several
  disease mechanisms
• Each mechanism is composed of several component
  causes
• There could be several case definitions for a
  particular disease

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DALY YLL YLD

• DALYs are calculated for disease or health
  condition
• It is sum of
• Years of Life Lost (YLL) due to premature
  mortality in the population and
• The Years Lost due to Disability (YLD) for
  incident cases of the health condition
• DALY YLL YLD

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Disease event

• Usually it is described by signs and symptoms
• Pathophysiological changes at certain anatomical
  location
• Root causes are generally categorized as genetic,
  environmental or etiological

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Clean hands save lives

• You may not find Panacea but you could probably
  find intervention to prevent several diseases
• Hand-washing has been shown to cut the number of
  child deaths from diarrhea (the second leading
  cause of child deaths) by almost half and from
  pneumonia (the leading cause of child deaths) by
  one-quarter
• Reference Global Hand-washing Day 15 October,
  Planners Guide
• Conclusion Backend measures uproot the disease
  while front end measures prune the disease

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Interventions against diarrheal disease

• Cost in proportion to hygiene promotion
• Cholera immunizations 1655
• Rotavirus immunizations 1627
• Measles immunization 804
• Oral rehydration therapy 450
• Hygiene promotion
• (including hand washing) 1
• Reference Global Handwashing Day, 15 October,
  Planners Guide

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Economic development

• Hygiene promotion a economic development
• Lower infant mortality rates a higher
  economic growth
• WHO estimates that a 10 year increase in average
  life expectancy at birth translates into a rise
  of 0.3 0.4 in economic growth per year

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Sanitation and hygiene, and diarrhea vaccine

• Good sanitation and hygiene prevents invasion of
  several disease causing microorganisms
• Monovalent vaccine causes selective invasion to
  prevent multiplication of a single serotype /
  species of microorganism in a responsive patient.
  The commercial life of vaccine may last till the
  microorganism mutates to gain resistance to
  vaccine
• Hence, backend measures uproot the disease while
  front end measures prune the disease

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Transmission of the disease (!)

• Whatever is transmitted is not the disease but
  the component cause of the disease in a
  predisposed patient
• The transmission results in specific immunity in
  resistant individual and subclinical or clinical
  infection in a susceptible case

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Susceptibility

• The susceptibility to the disease is due to the
  host and/or environmental factors
• Non-response to vaccine could also be due to the
  host and/or environmental factors
• The policy of research for so called communicable
  diseases should be primarily based on creation of
  healthy environment or healthy host X
  environment interaction

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Vaccine policy

• Hence vaccine in general is not a substitute to
  creating healthy environment or healthy host X
  environment interaction it is complimentary
• Poor vaccine policy could be the result of lack
  of application of disease informatics

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Inductors of probiosis provide environmental
vaccines

• Could reduce hostility of environment
  (microecology)
• The gut, vaginal or body environment could be
  altered by induction of probiosis
• Evading the factors that cause dysbiosis could be
  an inexpensive method in bringing down disease
  burden
• Should it be part of primary research policy for
  research?

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Oral Polio Vaccine goes oral to environmental

• Prepared using a live, attenuated virus, used
  during pulse polio campaign
• Excreted vaccine virus is expected to spread
  through water
• Vaccinee potentially precludes transmission of
  the wild poliovirus to other hosts
• Could an arboviral vaccine virus be disseminated
  through mosquitoes for prevention of arboviral
  diseases?

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• Thank you