Prioritisation in population health
- priority = maximum benefit for maximum number of people
- health resources are finite
- prioritisation has opportunity cost (some people will lose out)
- individual vs population needs resourcing
- ethical + evidence based judgement
- difficult comparing outcomes (apples vs oranges)
Reasons for GBD Project
- incomplete data from many countries
- available data focused on deaths, barely anything on non-fatal outcomes
- lobby groups give distorted images of importance of problems
- unless the same approach is used to estimate the burden of different conditions, it is difficult to decide which conditions are most important and which strategies may be the ‘best buys’
Aims of GBD Project
-to use a systematic approach to summarise the burden of diseases and injury at the population-level based on epidemiological principles and best-available evidence
→to aid in setting health service and health research priorities
→to aid in identifying disadvantaged groups and targeting of health interventions
-to take account of deaths as well as non-fatal outcomes (i.e. disability) when estimating the burden of disease
DALYs
- DALYs: disability adjusted life years
- summary measure that combines data on premature death and non-fatal health outcomes to represent the health of a particular population as a single number
- considers premature mortality (before life expectancy of country) and non fatal health outcomes (disability)
- uses YLD (years lived with disability) and YLL (years of life lost)
- year with disability is based on disability weight of outcome
- YLD represents morbidity, YLL represents mortality
Enables comparison between diseases to:
- prioritise health interventions
- monitor health interventions
- assess changes of disease burden over time
YLL and YLD: data needed
YLL
- number of deaths from the disease in a year
- years lost per death relative to an ideal age
YLD
-number of cases with non-fatal outcome with the disease
-average duration of non-fatal outcome until recovery / death
-disability weight (e.g. lung cancer - 0.29)
→weight is anchored on a disability scale of 0 - 1, 1 is death and 0 is full health
→panel of experts have argued and come up with this scale
GBD disease grouping
Group 1: Communicable disease (infectious) and perinatal conditions (early life)
Group 2: Non-communicable disease (chronic)
Group 3: Injuries
NZ DALYs trend
-mainly non-communicable disease with some injuries there
Overall global DALYs trend
- communicable diseases coming down except HIV
- non communicable diseases increasing overall
- injuries increasing overall
- mental health was something not picked up before by fatalities (GBD discovered this as it looks as non fatal outcomes)
- GBD also identified injury as a key issue
DALYs high income vs low income countries
- high income countries - most deaths over age of 80 years
- sub-saharan Africa - barely surviving to their 5th birthday - GBD captures not just number of deaths but when - young people dying (particularly in low income countries) contributes many YLL and a lot to DALY burden
- helps us direct interventions to prevent this happening
- low income: lots of group 1, lots of group 2
- middle income: all groups mixed
- high income: mainly group 2, little group 1
- same amount of injury in all incomes
Gains of DALYs
- drew attention to previously hidden burden of mental health problems and injuries as major public health problems
- recognises non-communicable diseases as a major and increasing problem in low and middle income countries (not just a rich country problem)
Challenges of DALYs
- who should decide disability weights? → global panel is contentious issue
- reasonability of applying one set of disability weights globally due to differing legislation and support service strength in countries
- how does physical and social environment influence disability experiences
2 Major ones
- disability weights do not vary with a persons social position, where they live, access to health care, or other life circumstances
- GBD project criticised for potential to represent people with disabilities as a burden → medical model
Models of Disability
Social model
- disability is a social issue caused by policies, practices, attitudes or the environment
- focuses on ridding society of barriers rather than curing
Medical model
- disabled people defined by illness or condition
- focus on curing, individual problem, dependency
HIV: trends
- communicable and perinatal conditions gone down
- HIV/AIDS ranking gone up from 1990-2019 in YLL, YLD and DALYs
- does not follow epidemiological transition
- heterosexual transmission is dominannt mode
- 95% were in low and middle income countries
- of new infections among people 15 or older, around 39% are people aged 15-24 (mainly female in Sub-saharan Africa)
- low access to treatment is especially marked in low and middle income countries
- only a minority (36%) treated in Western and Central Africa
- majority treated in Europe and America (around 70%)
- number of people living with HIV continues to rise due to life-prolonging treatment (less deaths)
HIV: background
- celebrity status
- most people affected → celebrities in Europe and America → brought it to agenda of public health specialists
- attatched to discrimination and stigma
- a lot of children got the disease got it from their parents, and lost their parents to the disease, had to live with the stigma of HIV/Aids
- we know have better forms of treatment and testing, people are not dying as much as when the disease was previously emerging
HIV: demands from public health epidemiologists
- human rights and fears (different perspectives and situations)
- screening (in the absence of a known agent and test)
- request for definitive evidence
- costs for screening versus numbers to save
HIV: what we know now overview
- several modes of transmission identified - facilitate prevention
- there are cheap, reliable and HIV-specific screening tests now
- we know it is caused by a virus
- better treatment options
- no vaccine still
Two common situations where you may be tested:
- pregnancy
- donating blood
HIV: in NZ
- low prevalence country
- 75% are men who acquired infection via sex with men
- routine antenatal screening (no mother to child transmission since 2007)
- 2008 survey in Auckland: 6.5% of men who have sex with men were infected, 20% did not now HIV status
- need to encourage condom use
- no room for complacency
HIV: first outbreak
Indiana, America
- HIV declared public health emergency
- 160 cases in 4 months
- usual is <5 cases/ year
- community with long history of unemployment, poverty and general addiction
- consistently lower health status in State: slow roll-out of Affordable Care AC
- country was without HIV testing centre since 2013
Response
- public education
- outbreak investigation
HIV: high risk groups
- homosexual men
- heterosexual relations ( dominant mode)
- sex workers
- injecting drug users
- those receiving injections with unsterilized needles (low resource settings)
- infants born to ot breast fed by untreated HIV+ mothers
- anyone receiving unscreened blood
HIV: feminisation of the epidemic
- proportion of HIV+ women has steadily increased (41% 1997 - 51% 2002)
- leading cause of death for women of reproductive age worldwide
- experience of violence is associated with a three-fold increased risk of HIV infection
- HIV is not only driven by gender inequity but also entrenches gender inequity leaving women more vulnerable to its impact
Women are more likely -to face barriers in accessing HIV prevention, treatment and care services -to face barriers to education -to experience poverty Due to societal factors
HIV: human rights and women
-women rights to safe sexuality and to autonomy in all decisions relating to sexuality is intimately related to economic independence
→this right is most violated in those places where woman exchange sex for survival as a way of life
-not about prostitution but a basic social and economic arrangement between the sexes which results from
→poverty affecting women
→male control over women’s lives in a context of poverty
-unless and until the scope of human rights is fully extended to economic security, women’s rights to safe sexuality is not going to be achieved
→the right to not live in abject poverty
HIV: prevention and control
Safer sex
- media campaings and wider policy strategies to reduce stigma and discrimination
- education approaches
- condoms: promote use, increase availability, reduce cost
Safer products (and related practices)
- screen blood products for HIV
- needle and syringe exchange programs
Increase access to healthcare
-voluntary testing and counseling to reduce risk of sexual transmission
Mother to child transmission
- without treatment about ⅓ children born to women HIV+ will become infected either in the womb, at birth or being breastfed
- the risk is greatly reduced by screening pregnant mothers and treating those who are HIV+ with antiretroviral drugs
HIV: determinants
- gender inequities (rules governend sexual relationships, negotiating condom use, sexual abuse/violence, problems with disclosure, partner notification and confidentiality)
- poverty and low social status (consequent limited access to education and reproductive health services)
- social norms, stigma and discrimination (that prevent access to prevention efforts and treatment → inequitable distribution in the risks of HIV infection → inequitable distribution of HIV infection among the low SES groups, women and young people)
HIV: lessons
- surveillance, investigation of risk factors and health promotion were crucial in establishing prevention efforts well before virus was discovered
- subsequent biomedical and pharmaceutical innovations provided rapid tests for HIV and treatment options that improve quantity (YLL) and quality (YLD) of life
- treatment does not replace importance of prevention
