PHEALTH Flashcards
Name two measures to characterise the Burden of Disease. Briefly explain these measures and how they differ from each other (6)
- Years of Life Lost (YLL) is a measure of how many healthy years that would have been lived are lost because of premature death. Sometimes this is called Potential Years of Life Lost or PYLL.
- Disability-Adjusted Life Years (DALYs) is a measure of both the years that would have been lived that are lost because of premature death, as well as the years that are lived with disease and/or disability.
- Prevalence or Incidence are rates of illness or injury. They are calculated based on a population denominator.
- YLL takes only mortality into account while DALYs takes mortality and morbidity into account.
- Prevalence and incidence do not take account of the years lost to illness and disease or years lived with disability.
If you wish to examine the burden of disease in the province due to brain cancer, a number of different measures, such as Years of Life Lost (YLL)’ and Disability Adjusted LifeYears (DALYs) can be used to characterise the burden of disease. Define the terms Years of Life Lost (YLL) (1) and Disability Adjusted LifeYears (DALYs) (2)
Years of Life Lost, YLLs A measure of premature loss of life due to a particular disease (It takes into account death due to a particular disease. Some methods take into account age weighting and discounting).
DALYs combines both mortality and morbidity associated with a disease into one index/measure. It takes account of years lived with a disease by converting it using a disability index into a value that can be added to the complete disability caused by death. In this way, you can sum the effect of morbidity and mortality, and you can compare different diseases that have different impacts.
As a result of the stroke, Mr Sher has difficulty walking unaided. Is this an impairment, a disability or a handicap? Briefly motivate your answer (2)
Disability (½) Disability is the functional deficit that arises from an impairment. In Mr Sher’s case, his impairment was his unilateral weakness. The loss of function that resulted from the weakness is the inability to walk (1½)
- It is a disability. He cannot function or walk without his aid.
- Impairment: physical or mental defect at the level of a body system or organ.
- Disability: Consequence of the impairment in terms of functional performance and activity
- Handicap: A physical, mental or emotional condition that affects the patient’s performance.
Claire is a 18-month old baby who is admitted to Red Cross Hospital because of a viral bronchiolitis and for regular observation overnight. The nurses on duty regularly check up on her and monitor her temperature, pulse and respiratory rate.
In the early hours of the morning, while having her nappy changed by a nurse, another baby cries out sharply, and the nurse turns away from Claire’s cot without closing the side, just for a minute. Claire rolls over and falls out of the cot onto the floor, injuring the side of her head badly. The nurse calls for help as Claire begins screaming with pain and fright, and a paediatrician on duty, Dr Williams, is quickly called to help assess the situation and manage Claire appropriately.
As the night passes, the nurses realise that Claire continues to cry and has begun to vomit. They call the paediatrician again and Dr Williams re-examines the baby. He notes that she is showing anisocoria (unequal sizes of pupils) and that her level of consciousness appears decreased. He is also concerned about the way she is gasping for air. Dr Williams immediately sends Claire for a CT scan of her head.
In the long-term, Claire risks developing significant neurological impairment if not properly treated. For example, she could grow up with weakness in her upper and lower limbs on one side and with difficulty in speaking. This may affect her ability to walk unaided, go to school or socialise with friends. Briefly explain and contrast the concepts of impairment, handicap and disability using Claire’s situation as an example (6)
- Impairment is the loss of, or abnormality in, psychological, physiological or anatomical function or structure (e.g. left sided hemiparesis)
- Disability is the functional consequence of the impairment – inability to perform a ‘normal’ function (e.g. cannot walk unaided, cannot run)
- Handicap is the difficulties Claire will experience as a result of her disability (e.g. will be unable to school properly, or be able to socialise with her friends)
The percent of years of life lost (YLL) due to stroke in 2000 amongst men and women was lower than in 1996 (refer to table below)
Briefly explain four (4) possible reasons for the difference in these results (4)
The actual death rates due to stroke could have declined
The percent of YLL of stroke could appear lower because mortality rate of another health condition may have an increased since 1996 (e.g. HIV). This phenomenon is called “Competing cause of death”
The data collection procedure may have changed between 1996 and 2000.
The type of data analysis may have changed between 1996 and 2000.
Stroke is a major cause of ill-health in South Africa.
Briefly explain the differences between the various measures used to characterise the Burden of Disease in South Africa (6)
Mortality rates are the simplest measure to estimate. However, they take no account of premature loss of life.
Years of Life Lost, YLLs, (also called Potential Years of Life Lost, PYLLs) takes account of premature loss of life. The WHO method (Global Burden of Disease Study, Murray and Lopez, 1996) further takes account of other factors such as age weighting (to value years lost in productive adult life) and discounting (to take account of the human tendency to value the saving of a year of life now higher than a year of life saved later). Both YLLs and simple mortality rates only take account of death due to a particular disease.
Disability Adjusted Life Years (DALYs) combine both mortality and morbidity in one index. It takes account of years lived with a disease by converting it using a disability index into a value that can be added to the complete disability caused by death. In this way, you can sum the effect of morbidity and mortality, and you can compare different diseases that have different impacts. For example, stroke might cause lots more disability than mortality when compared to an infectious disease such as cholera. A DALY estimate will take this into account so that you can compare the Burden of Disease due to stroke with that due to cholera. Note that there are many criticisms of the DALY methods (see page 269 of your textbook) principally because it values young productive adults over others in society and does not take socio-cultural factors adequately into account.
In 1996, stroke was the 5th leading cause of death in men and the 4th leading cause in women. In 2000, stroke was the 9th leading cause of death in men and the 6th leading cause of death in women.
Briefly explain four (4) possible reasons why there was a decrease in the number of deaths due to stroke as recorded from 1996 to 2000 in South Africa (4)
- The actual death rates due to stroke could have declined
- The percent could look lower because another cause has increased (e.g. HIV). This phenomenon is called “Competing cause of death”
- The way the data were collected may have changed between 1996 and 2000.
- The way the data were analysed may have changed between 1996 and 2000.
Given that the death rate from stroke is still very high, outline three (3) specific examples of preventative measures that could be implemented (3)
From a public health point of view, you might want to devote resources (money, human resources, capital) and other preventive and policy initiatives to tackling this problem as it is a common cause of death and disability. Therefore health promotion campaigns that target lifestyle factors such as eating healthily (reduced fat, sugar and salt intake), regular exercise, moderate alcohol consumption and tobacco control policies
Define primary, secondary and tertiary prevention of disease and apply these concepts to the prevention of stroke (9½)
Primary Prevention Prevention of disease occurrence (1) Address NB modifiable risk factors: (½) o Dietary: reduce salt & sugar intake, increase fruit & veg intake (½) o Increase physical activity (½) o Detection & Mx of HT (½)
Secondary Prevention
Aims to reduce the impact of a disease or injury that has already occurred (1)
Daily, low-dose aspirin/ antiplatelet agents (½)
Carotid endarterectomy for carotid stenosis, TIA, non-disabling strokes (½)
Diet and exercise programs to prevent further strokes (½)
National Dietary guidelines & food policies to reduce sugar and salt consumption (½)
E.g. Taxing sugar sweetened beverages (½)
Rural villages: teach community workers to recognize stroke (FAST approach) (1)
Tertiary Prevention
Aims to soften the impact of an ongoing illness or injury that has lasting effects (1)
Stroke rehabilitation programs (1)
• The percent of years of life lost (YLL) due to stroke in 2000 amongst men and women, decreased after this information was measured in 1996 (refer to table …..)
Explain briefly the possible reason/s for the difference in these results (4)
The actual death rates due to stroke could have declined
The percent of YLL of stroke could appear lower because mortality rate of another health condition may have an increased since 1996 (e.g. HIV). This phenomenon is called “Competing cause of death”
The data collection procedure may have changed between 1996 and 2000.
The type of data analysis may have changed between 1996 and 2000.
