Online course on data analysis and report writing for civil registration based vital statistics 12 July to 10 September 2021 1 Introduction Mortality rate A measure of the frequency of occurrence of death in a defined population during a ID: 1041813
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1. Module 7Age specific mortality indicatorsOnline course on data analysis and report writing for civil registration based vital statistics 12 July to 10 September 20211
2. IntroductionMortality rate:A measure of the frequency of occurrence of death in a defined population during a specified interval.These rates provide a starting point for examining the health of a population.
3. Understanding the health of a populationWe have tabulated deaths by year and sex. There is not much that we can draw from the number of deaths.A large number of reported deaths may not necessarily indicate that there are more health issues in a population, but would be a result of a large population.Consider Niue and Fiji. Higher number of deaths in Fiji will not necessarily imply greater health issues/ that its more risky living in Fiji; A higher number of deaths is expected from the larger population.Dividing the deaths by the population gives a better understanding of mortality in a given population.
4. Reminder: Crude Death Rate Average number of deaths from 2013-2017 is 250, we will need to divide this by our midpoint population. Our midpoint is July 1, 2015. (Why?)Let’s assume the population was 15,645 on July 1, 2015. We then perform the calculation: = 3.2We can say there were an average 3.2 deaths per 1,000 population per year between 2013 and 2017. The CDR is also heavily influenced by the population structure and cannot be directly compared.
5. The CDR is larger in populations where older people comprise a larger proportion of the population. Population pyramids are a useful way of seeing the age and sex structure of our population.
6. Brainstorming – which rate to choose? What types of deaths do you commonly see in your country? Ages, cause, region? Who uses this information and what for?
7. Age specific mortality rates An age‐specific death rate (ASDR) is the number of deaths per 1,000 people of a given age group in a given time periodUse this when an age group is disproportionately affected (e.g. for maternal deaths use ages of child-bearing women) ASDR (25-29) in 2020= x 1000 ASDRs help us to know how old people are when they die Age group No. Deaths PopnASDR25-292502500=250/2500*1000
8. Graphing age-specific mortalityThe typical pattern for age‐specific mortality is J‐shapedMortality is relatively high among infants and young children, after which it declines rapidly, reaching its lowest usually around the 10‐14 year age group.It then gradually starts to edge up as young adult women are at risk for mortality due to childbirth and young adult men are at risk due to accidents and incidental causes such as suicide.Mortality continues to increase into the older adult age groups and generally starts to rise more rapidly among the oldest age groups in the population. As a general rule, mortality rates start to increase exponentially beyond age 35 or so.
9. Graphing age-specific mortality
10. Graphing age-specific mortalityGraphing age-specific rates on a normal numeric scale is problematic –note the loss of detail.
11. Graphing age-specific mortality
12. To graph using log scale The primary purpose of graphing the natural log of ASMRs is to examine the data for irregular or implausible changes from age to age. In countries with high maternal or injury mortality in young adults, death rates will rise steeply around age 15 years, peak at age 25, and decline to a new low at about age 35 years old.From about age 35 onwards, they rise linearly with age. A departure from this linear pattern in adult death rates suggests that deaths are being selectively (by age) underreported or that there is misreporting of the correct age of death.
13. Graphing your data Graphing ASMR:Plot your ASMR by age groups Click on the graph axis you want to changeFormat Axis, Logarithmic scaleSelect the "Logarithmic scale" tab under the Axis options tabWhat does the shape of your graph tell you about age‐specific mortality? Describe the patterns by age group.
14. Age standardised mortality rateThe age structure of the population can affect mortality indicators such as the crude death rate, making comparisons between populations unfeasible.To compare mortality between populations, or within the same population over time, we take our age‐specific mortality rates and apply them to a standardized population. The direct standardization process eliminates the effect of the age structure by using a single age structure as a standard for all populations being compared.
15. Example: population distributions A key goal in Australia is to reduce the inequalities faced by Aboriginal and Torres Strait Islander people and provide life outcomes that are equal to all Australians. Mortality rates are a key indicator (reduced death rates, increased life expectancy, lower numbers of deaths from preventable causes including suicide) Crude death rate for Aboriginal and Torres Strait Islander people is 4.6. Crude death rate for non-Indigenous Australians is 6.7. Age structure of the population means these rates are not comparable.
16. Example: population distributions Age groupsAboriginal and Torres Strait Islander people Non-Indigenous people 0-411.36.05-911.16.210-1410.96.015-1910.15.820-249.16.725-298.37.330-346.77.335-395.67.040-445.06.345-495.46.750-544.76.155-594.06.360-643.15.665-692.25.070-741.44.375+1.37.2
17. Age-standardised mortality rate formula SR is the age-standardised rate for the population being studiedri is the age-group specific rate for age group i in the population being studiedPi is the population of age group i in the standard population
18. Age standardised mortality rateMethod: To standardize our population we would apply the age group percentage listed under the world average to our total population.For the purposes of this course, we will use the WHO World Standard Population Distribution.
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20. Principles for age-standardisation 1. Denominators should never be less than 30 (population size). 2. Numerators should try and be at least 20. Can go to 10 in some circumstances but never calculated for smaller numbers. Combine years/cohorts etc to form a more robust numerator. 3. Ideally age-specific rates should be calculated on 5 year age bands. E.g. 0-4, 5-9, 75+ etc. Can go to 10 year age bands if required. Never produce age-standardised rates on 20 year age bands, these are too broad. 4. Age-standardised rates should not be used in isolation. Use counts of death, rate ratios, age-specific rates to provide as much information as possible. 5. For conditions restricted to specific age groups (e.g. infants) use age of interest.
21. Infant and Child mortalityInfant mortality rate (IMR) and Under five mortality rate (U5MR) are important indicators for development IMR and U5MR are key indicators of Goal 3 of the sustainable development goals targeting good health and wellbeing Many of the causes of death in these age-groups are amenable to interventionsSDG 3: Ensure healthy lives and promote well-being of all at all ages Target 3.2: By 2030, reduce neonatal mortality to at least 12 per 1,000 live births and under 5 mortality to at least 25 per 1,000 live births.
22. Life expectancy and infant mortality
23. Measures of infant and child mortalityUnder 5 mortality
24. Neonatal mortality rateNeonatal mortality rate (NNMR):NNMRMay be subdivided into early neonatal deaths, occurring during the first seven days of life, and late neonatal deaths, occurring after the seventh day but before 28 completed days of life.Considered to be a useful indicator of maternal and newborn health and care. As IMR falls and fewer deaths are attributed to infectious diseases and environmental influences, a greater proportion of infant deaths would be expected to occur in the neonatal period. - The neonatal mortality rate should not increase as this occurs.
25. Major causes of infant mortalityNeonatal Period Birth complications Prematurity and other developmental conditions Congenital conditions (Malnutrition) (Infectious diseases) Conditions in mother are keyPost -neonatal Period Malnutrition Infectious Diseases (External causes- accidents and injuries)
26. Infant mortality rateInfant mortality rate (IMR):IMRMeasures such as IMR and NNMR should always be aggregated over several years and reported with confidence intervals due to the small population size and subsequent instability in these measures. Trends should be evaluated over the longer term rather than year to year.
27. Under five mortality rateUnder five mortality rate (U5MR):U5MRAn important summary measure of development as it looks at the overall impact of mortality on early childhood.
28. Assessing your data for plausibilityInfant and child deaths may be under-reportedWhy would this be?Is this possible in the local contextNeed to compare to other sourcesCensus/ DHS etcAre the proportions plausible?What proportion of the infant deaths are neonatal? Is this consistent with what you know of your health system?
29. Other rates of mortality frequency Sex specific rates: adjust numerators and denominators by male/female only Rates for specific geographical areas: adjust numerators and denominators by region of interest Groups in the community including country of birth, ethnicity: adjust numerators and denomators Cause specific mortality: Adjust numerator by cause of interest
30. Assignmentcreate a summary table