BME 301

Lecture Two

Review of Lecture 1

Course organization Course goals Four questions we will answer Technology assessment – The big

picture What is health? Role of WHO Health data and uses

Overview of Lecture 2

What are the major health problems worldwide? Leading causes of mortality by age

Developed world Developing world

A Tale of Two Girls

One View of The World Developed Countries Developing Countries

There is no universally accepted definition of what a developing country is

Usually categorized by a per capita income criterion

Low income developing countries: <$400 Middle income developing countries: $400-

$4,000 WTO members decide for themselves if

they are a developing country; brings certain rights

UN: Least Developed Countries

In 1971, UN created a least developed country member category Countries apply for this status Low national income (<$900 per capita

GDP) Low levels of human capital

development Economic vulnerability Originally 25 LDCs

As of 2001, 600 million people live in world’s 49 least developed countries

Map of LDCs

Health and Other Data in LDCs

Average per capita GDP: LDCs: $235 All other developed countries: $24,522

Average life expectancy: LDCs: 51 years Industrialized nations: 78 years

1 child in 10 dies before his or her 1st bday in LDCs

40% of all children under 5 are underweight or suffering from stunted growth in LDCs

Half the population in LDCs is illiterate

Health and Other Data in LDCs

Mortality rate for children under five: LDCs: 151/1,000 live births High income countries: 6/1,000 live births

Average annual health care expenditures: LDCs: $16/person High income countries: $1,800/person

A child born today in an LDC is more than 1,000 times more likely to die of measles than one born in an industrialized country.

Leading Causes of Mortality Ages 15-44

Developing World1. HIV/AIDS2. Road accidents3. Inter-personal violence

Developed World1. Road accidents2. Self-inflicted injuries3. Inter-personal violence

Burden of HIV/AIDS

United States 0.8-1.2 million people have HIV/AIDs

(prevalence) 40,000-80,000 new HIV infections per

year (incidence) Within 10 years of infection:

50% develop clinical AIDS 40% develop illness associated with HIV 5-10% remain asymptomatic

Annual cost to treat: $15 billion

Burden of HIV/AIDS

Worldwide 40-100 million HIV infected worldwide 90% of HIV infections occurs in the

developing world 16,000 new infections per day 16 million people have died

Clinical Course of HIV/AIDS

HIV Infection Virus deposited on mucosal surface Acute infection (mono-like symptoms) Viral dissemination HIV-specific immune response Replication of virus Destruction of CD4+ lymphocytes Rate of progression is correlated with

viral load Latent Period

Clinical Course of HIV/AIDS

AIDS Immunologic dysregulation Opportunistic infections and cancers Risk of infections is correlated with

number of CD4+ lymphocytes Average patient with AIDS dies in 1-3

years

Pathophysiology of HIV/AIDS

http://health.howstuffworks.com/aids3.htm

Pathophysiology of HIV/AIDS

http://www.roche.com/pages/facets/4/hiv_life_cycle2.jpg

Treatments for HIV/AIDS Inhibit reverse transcriptase enzymes

Enzyme is specific to HIV Combinations of RTIs appear effective

Inhibitors of HIV protease HIV proteases are distinct from mammalian

proteases Most significant advance in HIV therapy yet

Highly Active Antiretroviral Therapy (HAART) Combination of three or more drugs

Fusion inhibitors Subject of new research

Treatment for HIV/AIDS

Prevention of HIV Infections Vaccines

Pre-clinical work in animals is promising Education, Counseling & Behavior mod.

Worked in the US for homosexual men Free needles for IV drug users

Societal debate Improved blood supply

Greatly decreased risk for hemophiliacs Screening and treating pregnant women

Area where interventions are well accepted

HIV/AIDS Historical Perspective

1981 CDC reported unexplained PCP in 5

previously health, homosexual men CDC reported Kaposi’s sarcoma in 26

previously healthy, homosexual men 1981-1982

Increased association with IV drug use, recipients of blood transfusions, hemophiliacs

1983 Virus isolated

HIV/AIDS Historical Perspective

1984 Virus shown to be causative agent

1985 ELISA test developed

Today: Broad spectrum of disease

Asymptomatic infection Clinical latency Advanced disease (AIDS)

Clearly sexually transmitted, and transmitted through blood products

US Burden of Disease: Road Accidents

Leading cause of potential years of life lost

$137.5 billion total economic cost in 1990 Rates:

15.6/100,000 US population died in 1993 40,115 Americans killed 3,200 killed were under 16 years of age

Rates >2X higher for males than for females Motorcycles: 20X higher death rate per mile

traveled 44% of fatalities related to alcohol use

Prevention: Road Accidents Laws:

Seat belts, Car seats, Air Bags Alcohol use Motorcycle helmets

Restraints Physics Unintended consequences

Education and counseling Seat belts, Car seats, Air Bags Alcohol use

Physics of Accidents/Restraints

Alcohol Related Deaths

Helmet Laws

Burden of Inter-personal Violence

75,000 Americans murdered in 1992 Persons at greatest risk:

Young males Minorities Persons with a history of criminal

behavior Persons in poor urban communities

Firearms (most often handguns) used in 70% of murders and 25% of aggravated assaults in US in 1992

Prevention of Inter-personal Violence

Causes: Complex: interactions between

personal, family, community and societal problems

Several factors can be screened in office: Ready availability of weapons Inadequate social problem solving skills Abuse of alcohol and drugs

Burden of Self-Inflicted Injuries

1993: Age-adjusted rate of suicide 11.2/100,000 31,230 suicide deaths 210,000 attempts per year

10,000 permanent disabilities 155,000 physician visits 259,000 hospital days 630,000 lost wage days $115 million in medical expenses

Highest rate of completed suicides Men >65 years old

Highest rate of attempted suicides Men and women ages 20-24

Risk Factors Associated with Suicide

Psychiatric illness Affective, substance abuse, personality, other

mental disorders Other risk factors

Social adjustment problems Serious medical illness Living alone Recent bereavement Personal history of suicide attempt or

completion Divorce or separation Unemployment

Methods of Suicide

Most common: Firearms are used in 60% of suicides

2nd leading cause: Men: Hanging Women: Drug overdose or poison

Alcohol is involved in 25-40% of suicides

Screening and Prevention

50-66% of all suicide victims visit physician <1 month before event

10-40% in the preceding week Hard to identify who is at risk

Direct questioning has low yield General questions about sleep

disturbance, depressed mood, guilt and hopelessness

Survey instruments aren’t good at predicting what will happen

Screening for Suicide Risk How do we quantify the efficacy of such

questionnaires? Goal of screening:

Catch as many positives as possible, even at the risk of some false positives

Sensitivity: Se = probability of testing positive if you will commit

suicide

Sensitivity of best questionnaires: 56% (low)

suicidecommit who#

positive test who#Se

Screening for Suicide Risk How many false positives result?

Positive predictive value: PPV=probability of committing suicide if you test

positive

PPV of best questionnaires: 3% (pathetic)

positive test who#

suicidecommit and positive test who#PPV

Summary of Lecture Two

Developing countries Leading causes of mortality: ages

15-44 Developing world

1. HIV/AIDS2. Road Accidents3. Interpersonal violence

Developed world1. Road accidents2. Self-inflicted injuries3. Interpersonal violence

Assignments Due Next Time

WA1 HW1