Measures of Mortality 11/28/2018

- Mortality is a term which means “death” or describes death and related issues. 11/28/2018

Why look at mortality rates? 1- Expressing mortality in quantitative terms allow comparison of death: 1- between people in different geographic areas or different countries. 2- between subgroups in the a population or country. 11/28/2018

2- Mortality rates can serve as a disease Severity, and can help to determine of whether the treatment for a disease has become more effective over time. 11/28/2018

Refer to as crude because: Crude rates: How they calculated? Crude rates are calculated for the entire population. Refer to as crude because: They ignore factors which may affect death rate such as: gender, age, race, economic status …. 11/28/2018

Mid-year population for the same year and same locality Crude Death rate (CDR): Number of all deaths due to all causes in a certain year and within certain locality x 1000 Mid-year population for the same year and same locality Example: Suppose area X in 1432 H, we have: 1- 1200 deaths, all causes. 2- The area's mid year population was 150,000. 11/28/2018

3-Find crude death rate in 1432H? Numerator: number of deaths all causes = 1200 Denominator: Mid-year population =150,000 CDR = 1200 x 1000 = 8/1000; 150,000 that is, 8 deaths per 1000 population. 11/28/2018

CMR By Sex And Nationality In The KSA (2004 to 2010) السنة سعوديون غير سعوديين الجملة SAUDI NON-SAUDI TOTAL YEAR ذكور اناث جملة MALE FEMALE 2004 4.7 3.9 4.3 3.4 3 3.3 3.8 4 2005 2.9 4.2 3.7 2006 4.6 3.2 2007 2.8 3.6 2008 4.5 4.1 3.5 2009 2.7 2010 4.4 11/28/2018

Maternal mortality rate Country Crude death rate Crude birth rate Infant mortality rate Maternal mortality rate   Per 1000 Per 100,000 Saudi Arabia 3.8 22.1 18.5 16 Yemen 7.0 38.6 53.3 200 Palestine 3.6 35.9 22.2 32  Iraq 6.3 36.6 34.6 63 Bahrain 2.8 20.7 20 Emirates 1.4 14.0 10.9 12 Oman 11 Qatar 1.6 14.1 9.0 6 Jordon 26.4 4.1 21.0 11/28/2018

Why Mid-year population? For example, for the crude death rate the number of persons exposed to the risk of dying (denominator): includes: Persons alive in Muharram 1 of the year previous year. 11/28/2018

adjustments made for persons who moved in or out. plus all persons born during year minus all persons who die during year, adjustments made for persons who moved in or out. 11/28/2018

The population at risk will be the population on Rajab1. A common solution to this problem of determining the population at risk is to estimate the population at mid-year. In our example (1432H): The population at risk will be the population on Rajab1. 11/28/2018

Cause-specific Mortality Rate • Is Mortality from a specified cause for a population during a specified time period. • The numerator is the number of deaths from that cause. The denominator remains the size of the population at the mid-point of the time period. 11/28/2018

Calculate mortality rate due to TB. Example: In the previous example: suppose the tuberculosis death in 1432H was 5. Calculate mortality rate due to TB. Numerator: number of deaths due to TB = 5 Denominator: Mid-year population 150,000 Mortality rate due to TB = (5/150,000) x 100,000 = 3.3/100,000

The Age Specific Death Rate Where: ASDR= The Age Specific Death Rate. Dx= Deaths for population at age x during the year. Px= Mid year Population for the population at age x 11/28/2018

Deaths Mid year Population Age Group 4143 73795 19 – 15 4740 48764 Deaths during the year and the population at the mid year for the different age groups Deaths Mid year Population Age Group 4143 73795 19 – 15 4740 48764 24 – 20 4304 43635 29 – 25 3883 63337 34 – 30 4062 34423 39 – 35 4597 26983 44 – 40 5085 24548 49 - 45 11/28/2018

The age Specific Death Rates ASDR Death Mid year Population Age Group 56 4143 73795 19 – 15 97 4740 48764 24 – 20 99 4304 43635 29 – 25 61 3883 63337 34 – 30 118 4062 34423 39 – 35 170 4597 26983 44 – 40 207 5085 24548 49 - 45 11/28/2018

Why Age Specific Death Rates? Can compare mortality at different ages. Can compare mortality in the same age groups over time and/or between countries and areas 11/28/2018

3- Infant mortality rates (IMR): Are the most common used rates for measuring the risk of dying during the first year of life. These rates are the most frequently used measures for comparing health services among nations. 11/28/2018

Infant Mortality Rate , Saudi Arabia (2000-2011) 11/28/2018

IMR = High infant mortality rates are: 1- Reflection of poor economic conditions 2- unmet health care needs and 3- other unfavorable environmental factors. IMR = number of infant deaths age 0-365 days X 1000 Number of live births during year 11/28/2018

Country Saudi Arabia Yemen Palestine Iraq Bahrain Emirates Oman Qatar Infant mortality rate   Per 1000 Saudi Arabia 18.5 Yemen 53.3 Palestine 22.2 Iraq 34.6 Bahrain 7.0 Emirates 10.9 Oman Qatar 9.0 11/28/2018

Suppose at KKU hospital, 20 infants died during 1432H Suppose at KKU hospital, 20 infants died during 1432H. The number of live births for the same year was 2600. Calculate IMR Numerator: number of infants died = 20 Denominator: Number of live births = 2600 IMR = 20 x 1000 = 7.7/1000 2600 11/28/2018

Neonatal mortality rate (NMR): That is; 7.7 infant deaths per 1,000 live births in 1432H. Neonatal mortality rate (NMR): Measures risk of dying among new born infants under the age 28 days. 11/28/2018

NMR = x 1,000 Example: In the previous example: number of deaths for infants under 28 days of age x 1,000 Number of live birth in the same year Example: In the previous example: suppose out of the 20 who died, 12 died in the first 28 days. Calculate NMR for 1432H. 11/28/2018

NMR = 12 x 1,000 = 4.6/1000 2600 4.6 deaths per 1,000 live births. Numerator: number died in ( 0- 28) days = 12 Denominator: Number of live births = 2600 NMR = 12 x 1,000 = 4.6/1000 2600 4.6 deaths per 1,000 live births. 11/28/2018

Postneonatal mortality rate (PNMR): Number who died after 28 days of age. For the previous example: The number of infants who died after 28 days of age is 8. (20 - 12 = 8). 11/28/2018

deaths for infants more than 28 days old through the age of 1 year PNMR = deaths for infants more than 28 days old through the age of 1 year x 1,000 Number of live birth in the same year 12 x 1,000 = 3.1/1000 PNMR = 2600 3.1/1000 deaths per 1,000 live births. 11/28/2018

Maternal Mortality Definition: ‘Maternal death’ is death of a woman while pregnant ,or within 42 days of termination of pregnancy. Irrespective of the duration or site of the pregnancy. 11/28/2018

Not from accidental causes From any cause related to, or aggravated by the pregnancy or its management Not from accidental causes 11/28/2018

Maternal Mortality Indicators Maternal mortality ratio (per 100,000 live births -or per 1000 live births) Maternal mortality rate (per 100,000 women of childbearing age) 11/28/2018

Maternal Mortality Ratio Number of women who die as a result of complications of pregnancy or childbearing in a given year per 100,000 live births in that year Represents the risk associated with each pregnancy, i.e., the obstetric risk 11/28/2018

The denominator is the number of live births during the same year. The numerator is the number of deaths in a year from puerperal causes. (complications of pregnancy, childbirth, puerperium). The denominator is the number of live births during the same year. 11/28/2018

Total maternal deaths for a period (year) Number of live birth in the MMRatio = Total maternal deaths for a period (year) x 100,000 Number of live birth in the same year Example: The year-end of 1432H report from the obstetrical ward: 11/28/2018

MMRatio= 1- was 3 deaths (2 abortions, 1 pregnancy complications). 2- The number of live born was as before (2600). Numerator: number of mothers died = 3 Denominator: Number of live births = 2600 3 x 1,000 = 1.15/1000 MMRatio= 2600 1.15/1000 maternal deaths per 1,000 live births 11/28/2018

Maternal Mortality Rate Number of women who die as a result of complications of pregnancy or childbearing in a given year per 100,000 women of childbearing age in the population Represents both the obstetric risk and the frequency with which women are exposed to this risk. 11/28/2018

Maternal mortality rate Country Maternal mortality rate Per 100,000 Saudi Arabia 16 Yemen 200 Palestine 32  Iraq 63 Bahrain 20 Emirates 12 Oman 11 Qatar 6 11/28/2018

Total maternal deaths for a period (year) MMRate = Total maternal deaths for a period (year) x 100,000 Number of women age 15 - 49 Example: The year-end of 1432H report from the obstetrical ward: 11/28/2018

1- was 10 deaths (2 abortions, 8 pregnancy complications). 2- The number of women aged 15-49 was: (250000). 10 MMRate = x 100,000 250000 = 4/100,000 11/28/2018

Number of individuals with the specified disease Case- fatality rate (CFR): (expressed usually as percent): CFR = Number of deaths during a specified period of time after disease diagnosed x 100 Number of individuals with the specified disease 11/28/2018

Example 1: At X city: 1) 110 cases of cancer in 1433H 2) 29 died in 1433H. Find CFR: Numerator: # died of cancer = 29 Denominator: Number with cancer = 110 CFR = 29 x 100 = 26.4% 110

Proportionate Mortality (PM): The proportionate of mortality from specified disease is defined as: PM = Number of deaths from a disease during a specified period of time x 100 Total deaths in the same time period 11/28/2018

1) 10 deaths from cardiovascular disease in 1427 Example 1: At X city: 1) 10 deaths from cardiovascular disease in 1427 2) 500 deaths from all diseases in 1427 Find PM: PM = 10 x 100 = 2% 500 11/28/2018

Years of potential life lost (YPLL) Is a measure of early deaths. Death occurring in the same person at a younger age involves a greater loss of future productive years than death occurring at an older age. Steps in calculation of YPLL: 1- subtract each person’s death from predetermined age (differs according to country). 11/28/2018

For example a person died at age 32, and suppose the predetermined age is 65, then this person has lost (65 – 32) = 33 years of life. The younger the age at which death occurs, the more years of potential life are lost. 2- ‘YPLL’ for each individual are then added together to yield the total YPLL. 11/28/2018

5 workers died because of exposure to toxic chemical. Example: 5 workers died because of exposure to toxic chemical. The ages of death were 20, 25, 30, 35, and 40 years. Use age 65 as the predetermined age. Calculate the YPLL for these 5 workers. And so find the mean YPLL. 11/28/2018

YPLL = (65 – 20) + (65 – 25) + (65 – 30) + (65 – 35) + ( 65 – 40) = 175. 2- The mean YPLL = 175/5 = 35 On average, the number of years of premature death among those workers who died is 35 years. 11/28/2018

Country Sex ratio Life expectancy Total fertility rate   Male Female Saudi Arabia 105 : 100 71 75 3.03 Yemen 61 60 5.48 Palestine 106 : 100 73 77 4.65 Iraq 70 4.86 Bahrain 103 : 100 76 81 2.63 Emirates 80 2.36 Oman 2.52 Qatar 102 : 100 74 1.92 Jordon 79 82 3.27 11/28/2018

Sex differentials: The average life expectancy of females is greater than that of males, partly due to biological factors and partly because of behavioral differences. Men smoke more tobacco, drink alcohol, have more motor vehicle accidents, engage in more 11/28/2018

dangerous occupation and are more prone to suicide. There is an Excess male mortality in many countries. Comparing the number of male deaths with the number of female deaths can be misleading due to sex ratio (more male babies being born and hence more deaths. 11/28/2018

Male excess mortality = x 100 Male death rate at age x To avoid the effect of sex ratio in mortality rate comparisons, the sex ratio of the age specific death rate, which is used to measure male excess mortality. This is obtained as: Male excess mortality = x 100 Male death rate at age x female death rate at age x 11/28/2018

For example, a male excess mortality of 150 would denote that the male death rate was 50% higher than the corresponding death rate for females. 11/28/2018

Male excess mortality Deaths Mid year Population females Males Females   females Males Females 2.85 12 36 8651 9103 3.09 15 48 9345 9676 2.83 21 60 10617 10696 2.69 27 72 10986 10877 2.59 33 84 10061 9902 1.98 45 90 8924 8692 1.80 57 99 7062 6811 11/28/2018

Sources of statistics on mortality 1- Death certificate: Specifies a number of demographic and social characteristics of the deceased and details about the cause of death. Death certificate can also include: birth place, marital status, education, residence, occupation. 11/28/2018

3- Cross-national data: 2- Vital statistics: Include mortality data on the number and causes of deaths, together with the age and sex of the deceased. 3- Cross-national data: Comparative data on mortality are published in the United Nation Yearbook and WHO Health Statistics Annual. 11/28/2018

Standardization A principal role in demography is to compare the mortality between two or more populations. The comparison of crude mortality rates is misleading. 11/28/2018

If the populations being compared differ greatly with respect to , for example, age or sex, that will affect the overall rate of morbidity or mortality. 11/28/2018

For example, age is an important determinant of mortality. An older population will have a higher overall mortality rate than a younger population. As a result, variations in age will complicate any comparison between two or more populations that have different age structures. 11/28/2018

This is achieved by using methods of standardization. One way to overcome this problem is to combine category specific rates into a single summary rate that has been adjusted to take into account its age structure. This is achieved by using methods of standardization. 11/28/2018

Methods of Standardization There are two methods of standardization commonly used: 1- Direct method 2- Indirect method). 11/28/2018

Direct Adjusted Rates Requires a standard population, to which the estimated age-specific rates can be applied Choice of the standard population may affect the magnitude of the age-adjusted rates, but not the ranking of the population

How to calculate standardized crude death rate? 1- Select a standard population, whose age distribution will be the standard for comparison. 2- calculate age specific death rate for the two populations (A and B). 11/28/2018

3- Calculate the expected number of deaths that would occur in a year if the standard population experienced the age-specific death rates (ASDR) of populations A and B. 4- Multiply each age group in the standard population by the corresponding ASDR for populations A and B. 11/28/2018

6- To calculate the age-standardized crude rate for each population: 5- Add the columns of the expected deaths for the two populations (A & B) to obtain the total expected deaths in the standard population. 6- To calculate the age-standardized crude rate for each population: Divide the total expected deaths for each population by total standard population. 11/28/2018

Population, Deaths, and Death Rate by Community and by Age Community B Age (year) Population Deaths Death Rate (per 1000) Under 1 1,000 15 15.0 5,000 100 20.0 1 – 14 3,000 3 1.0 20,000 35 15 – 34 6,000 6 35,000 35 – 54 13,000 52 4.0 17,000 85 5.0 55 – 64 7,000 105 8,000 160 Over 64 1,600 80.0 15,000 1,350 90.0 All ages 50,000 1,781 35.6 100,000 1,740 17.4 Death Rate (per 1000) 11/28/2018

Age – adjusted death rate (per 1000) (years) Standard population Death rate in A (per 1,000) Expected deaths at A’s rate in B B’s rate Under 1 6,000 15.0 90 20.0 120.0 1 – 14 23,000 1.0 23 0.5 11.5 15 – 34 41,000 41 41.0 35 – 54 30,000 4.0 120 5.0 150.0 55 – 64 15,000 225 300.0 Over 64 35,000 80.0 2,800 90.0 3,150 Total 150,000 35,6 3,299 17.4 3,772.5 Age – adjusted death rate (per 1000) 22.0 25.0 11/28/2018

x 1000 Calculation of standardized death rate Total standard population = 150,000 Expected deaths for pop A = 3299 Standardized death rate for pop A = Expected deaths pop A x 1000 Total standard population 11/28/2018

standardized death rate for pop A: 3299 x 1000 = 21.99 per 1000 150,000 The result indicates that pop A crude death rate would be 21.99/1000 if it has the same age structure as the standard population which far less than the observed crude death rate 35.6/1000. 11/28/2018

standardized death rate for pop B: Total standard population = 150,000 Expected deaths for pop B = 3,772.5 11/28/2018

Standardized death rate for pop B = Expected deaths pop A x 1000 Total standard population 3,772.5 x 1000 = 25.15 per 1000 150,000 11/28/2018

The result indicates that pop B crude death rate would be 25 The result indicates that pop B crude death rate would be 25.15/1000 if it has the same age structure as the standard population which far more than the observed crude death rate 17.4/1000. 11/28/2018

The result indicates that pop A crude death rate would be 21 The result indicates that pop A crude death rate would be 21.99/1000 if it has the same age structure as the standard population which far less than the observed crude death rate 35.6/1000. 11/28/2018

This ratio is called the Comparative Mortality Ratio (CMR). We can calculate: The ratio of the directly standardized rates to provide a single summary measure of the difference in mortality between the two populations. This ratio is called the Comparative Mortality Ratio (CMR). 11/28/2018

Comparative Mortality Ratio (CMR) calculated by dividing the overall age adjusted rate in country B by that of B. In our example: Comparative Mortality Ratio (CMR) = 25.15/21.99 = 1.14 11/28/2018

This CMR is interpreted as: after controlling for the affects of age, the mortality in Country B is 14% higher than in country A. 11/28/2018

Example 2: Table 2 presents crude mortality data for two populations (countries A and B). The overall crude mortality rate is higher for country A (10.5 deaths per 1,000 person years) 11/28/2018

compared with country B (7 deaths per 1,000 person years). Notice the ASDRs rates being higher among all age-groups in country B. For example, 18% of the population in country A are aged over 60 years compared with 6% in country B. 11/28/2018

Table 2. Crude mortality rates stratified by age for two populations (country a, B). Country B Age group # deaths/ 1000 Pop (M) Death rate # deaths Pop Death rate/ 0 - 29 7,000 6 1.2 6,300 1,500,000 4.2 30 - 59 20,000 5.5 3.6 3,000 550,000 60+ 120,000 2.5 48 6,000 50 Total 147,000 14 10.5 15,300 2,170,000 7

Country A has a much older population than country B. The reason for the difference between the crude mortality rates between country A and country B is that these two populations have markedly different age-structures. Country A has a much older population than country B. 11/28/2018

Table 3. Standard population Age group Pop 0 - 29 100,000 30 - 59 65,000 60+ 20,000 Total 185,000 11/28/2018

Age (years) Standard population Death rate in A (per 1,000) Expected deaths at A’s rate in B B’s rate 0 - 29 100,000 1.2 120 4.2 420 30 - 59 65,000 3.6 234 5.5 357.5 60+ 20,000 48 960 50 1,000 Total 185,000 10.5 1,314 7 1,777.5 11/28/2018

x 1000 Calculation of standardized death rate Total standard population = 185,000 Expected deaths for pop A = 1314 Standardized death rate for pop A = Expected deaths pop A x 1000 Total standard population 11/28/2018

1314 x 1000 = 7.1 per 1000 185,000 standardized death rate for pop A: The result indicates that pop A crude death rate would be 7.1/1000 if it has the same age structure as the standard population which is less than the observed crude death rate 10.5/1000. 11/28/2018

x 1000 Calculation of standardized death rate Total standard population = 185,000 Expected deaths for pop A = 1777.5 Standardized death rate for pop B = Expected deaths pop A x 1000 Total standard population 11/28/2018

standardized death rate for pop B: 1777.5 x 1000 = 9.6 per 1000 185,000 The result indicates that pop A crude death rate would be 9.6/1000 if it has the same age structure as the standard population which is more than the observed crude death rate 7/1000. 11/28/2018

We can calculate the Comparative Mortality Ratio (CMR) as: = 9.6/7.1 = 1.35 11/28/2018

CMR is interpreted as: After controlling for the affects of age, the mortality in Country B is 35% higher than in country A. 11/28/2018

Indirect Adjustment of Rates Used if age-specific rates cannot be estimated.

Indirect Adjustment of Rates Based on applying the age-specific rates of the standard population to the population of interest to determine the number of “expected” deaths. Steps in calculation: 1- Choose standard population and list its age-specific death rate. 11/28/2018

Suppose we selected population B as the standard population. List ASDR for population B. List the age distribution of the pop A in the next column. Calculate expected deaths for pop A by multiplying each age group by the corresponding ASDR for the standard population. 11/28/2018

Sum the column of the expected deaths. This total shows the number of deaths that would occur if population A experienced the ASDR of pop B. Calculate the standardized mortality ratio as: 11/28/2018

____________________ Standardized Mortality Ratio(SMR)= Total observed deaths In population (A) ____________________ Total expected deaths in a population (A) 11/28/2018

Standard death rate pop B Expected deaths in A at standard rates Age (years) Standard death rate pop B (per 1,000) Total population A Expected deaths in A at standard rates Observed Deaths A Under 1 20.0 1,000 15 1 – 14 0.5 3,000 1.5 3 15 – 34 1.0 6,000 6.0 6 35 – 54 5.0 13,000 65.0 52 55 – 64 7,000 140.0 105 Over 64 90.0 20,000 1,800.0 1,600 Total 17.4 50,000 2,032.5 1,781 11/28/2018

SMRA = 1781 / 2032.5 = 0.876 SMRB = 1.0 The result shows that the observed deaths in A were 12% lower than they would have been if A ASDR were the same as those of pop B. 11/28/2018

Standardized Mortality Ratio The ratio is exactly 1 if the observed and expected deaths are the same. If the SMR is greater than 1, more deaths have occurred than anticipated. If SMR is less than 1, fewer deaths have occurred than anticipated. 11/28/2018

We could also obtain an indirect standardized death rate (ISDR). This could be obtained by multiplying CDR of the standard population by SMR. CDR of B = 17.4 SMR = 0.876 ISDR = 17.4 x 0.876 = 15.24 11/28/2018

Example 2: Table 2 presents crude mortality data for two populations (countries A and B). The overall crude mortality rate is higher for country A (10.5 deaths per 1,000 person years) 11/28/2018

compared with country B (7 deaths per 1,000 person years). Notice the ASDRs rates being higher among all age-groups in country B. For example, 18% of the population in country A are aged over 60 years compared with 6% in country B. 11/28/2018

Table 2. Crude mortality rates stratified by age for two populations (country a, B). Country B Age group # deaths/ 1000 Pop (M) Death rate # deaths Pop Death rate/ 0 - 29 7,000 6 1.2 6,300 1,500,000 4.2 30 - 59 20,000 5.5 3.6 3,000 550,000 60+ 120,000 2.5 48 6,000 50 Total 147,000 14 10.5 15,300 2,170,000 7

Country A has a much older population than country B. The reason for the difference between the crude mortality rates between country A and country B is that these two populations have markedly different age-structures. Country A has a much older population than country B. 11/28/2018

Table 3. Standard population Age group Pop 0 - 29 100,000 30 - 59 65,000 60+ 20,000 Total 185,000 11/28/2018

Age standard rate ratio (B : A) = 9.6/ 7.1 = 1.35 Table 3. - calculation of the number of expected deaths for countries A and B applied to a standard population. Country A Country B Expected deaths 0 - 29 0.0012 x 100,000 = 120 0.0042 x 100,000 = 420 30 - 59 0.0036 x 65,000 = 234 0.0055 x 65,000 = 357.5 60+ 0.048 x 20,000 = 960 0.05 x 20,000 = 1000 Total expected deaths 1,314 1,777.5 Age adjusted rate 1,134/185,000 = 7.1/1,000 1,777.5/185,000 =9.6/1000 Age standard rate ratio (B : A) = 9.6/ 7.1 = 1.35 11/28/2018

Comparative Mortality Ratio (CMR) For our example: Comparative Mortality Ratio (CMR) = 9.6/7.1 = 1.35 This CMR is interpreted as: after controlling for the affects of age, the mortality in Country B is 35% higher than in country A. 11/28/2018

Total expected deaths (E) 9,540 Table 4. Number of expected deaths if the population B had the same age-specific mortality rates as Country A. Country B Expected deaths 0 - 29 0.0012 x 1,500,000 = 1,800 30 - 59 0.0036 x 550,000 = 1,980 60+ 0.048 x 120,000 = 5,760 Total expected deaths (E) 9,540 Total observed deaths (O) 15,300 Standardized Mortality Ratio (O/E) x 100 160 11/28/2018

The expected deaths in Country A are calculated by multiplying the age specific rate for Country A by the population of Country B in the corresponding age group. 11/28/2018

The sum of the age categories gives the total number of deaths that would be experienced in country A if it had the same mortality experience as country B. 11/28/2018

An overall summary measure can then be calculated, that is, the standardized mortality ratio (SMR), which is the ratio of the observed number of deaths to the expected number of deaths. 11/28/2018

SMR = Observed number of deaths (O) X 100% Expected number of deaths (E) SMR = 160 = 1.6 X 100 = 160 100 This means: The number of observed deaths in Country B is 60% higher than the number we would expect if Country B had the same mortality experience as Country A. 11/28/2018