Measures of Mortality 5192021 1 Mortality is a

Measures of Mortality 5/19/2021 1

- Mortality is a term which means “death” or describes death and related issues. 5/19/2021 2

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. 5/19/2021 3

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. 5/19/2021 4

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 …. 5/19/2021 5

Crude Death rate (CDR): Number of all deaths due to all causes in a certain year and within certain locality Mid-year population for the same year and same locality x 1000 Example: Suppose area X in 1432 H, we have: 1 - 1200 deaths, all causes. 2 - The area's mid year population was 150, 000. 5/19/2021 6

3 -Find crude death rate in 1432 H? 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. 5/19/2021 7

CMR By Sex And Nationality In The KSA (2004 to 2010) ﺍﻟﺠﻤﻠﺔ ﻏﻴﺮ ﺳﻌﻮﺩﻳﻴﻦ NON-SAUDI TOTAL ﺟﻤﻠﺔ ﺍﻧﺎﺙ TOTAL FEMALE ﺫﻛﻮﺭ MALE ﺳﻌﻮﺩﻳﻮﻥ SAUDI ﺟﻤﻠﺔ ﺍﻧﺎﺙ TOTAL FEMALE ﺍﻟﺴﻨﺔ ﺫﻛﻮﺭ MALE YEAR 4 3. 8 4. 3 3 3. 4 4. 3 3. 9 4. 7 2004 4 3. 7 4. 2 3. 3 2. 9 3. 4 4. 3 3. 9 4. 7 2005 4 3. 7 4. 2 3. 2 2. 9 3. 4 4. 2 3. 8 4. 6 2006 3. 9 3. 6 4. 2 3. 2 2. 8 3. 4 4. 2 3. 8 4. 6 2007 3. 9 3. 6 4. 2 3. 3 2. 8 3. 5 4. 1 3. 7 4. 5 2008 3. 9 3. 5 4. 2 3. 3 2. 7 3. 5 4. 1 3. 7 4. 5 2009 3. 5 4. 2 3. 3 2. 7 3. 6 4. 1 3. 7 4. 4 2010 5/19/2021 8

Crude Infant Maternal Country death rate birth rate 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 7. 0 20 Emirates 1. 4 14. 0 10. 9 12 Oman 3. 8 22. 2 18. 5 11 Qatar 1. 6 14. 1 9. 0 6 Jordon 5/19/2021 26. 4 4. 1 21. 0 63 9

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. 5/19/2021 10

• plus all persons born during year minus all persons who die during year, • adjustments made for persons who moved in or out. 5/19/2021 11

• A common solution to this problem of determining the population at risk is to estimate the population at midyear. • In our example (1432 H): The population at risk will be the population on Rajab 1. 5/19/2021 12

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. 5/19/2021 13

Example: In the previous example: suppose the tuberculosis death in 1432 H 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 14

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 5/19/2021 15

Deaths during the year and the population at the mid year for the different age groups Age Group 15 – 19 Mid year Population Deaths 73795 4143 20 – 24 48764 4740 25 – 29 43635 4304 30 – 34 63337 3883 35 – 39 34423 4062 40 – 44 26983 4597 45 - 49 24548 5085 5/19/2021 16

The age Specific Death Rates Age Group 15 – 19 20 – 24 25 – 29 Mid year Population 73795 48764 43635 Death 4143 4740 ASDR 56 97 4304 99 30 – 34 63337 3883 61 35 – 39 34423 4062 118 40 – 44 26983 4597 170 45 - 49 24548 5085 207 5/19/2021 17

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 5/19/2021 18

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. 5/19/2021 19

Infant Mortality Rate , Saudi Arabia (2000 -2011) 5/19/2021 20

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 5/19/2021 21

Country Infant mortality rate Per 1000 5/19/2021 Saudi Arabia 18. 5 Yemen 53. 3 Palestine 22. 2 Iraq 34. 6 Bahrain 7. 0 Emirates 10. 9 Oman 18. 5 Qatar 9. 0 22

• Suppose at KKU hospital, 20 infants died during 1432 H. 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 5/19/2021 23

• That is; 7. 7 infant deaths per 1, 000 live births in 1432 H. Neonatal mortality rate (NMR): • Measures risk of dying among new born infants under the age 28 days. 5/19/2021 24

NMR = 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 1432 H. 5/19/2021 25

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. 5/19/2021 26

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). 5/19/2021 27

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 PNMR = 12 2600 x 1, 000 = 3. 1/1000 deaths per 1, 000 live births. 5/19/2021 28

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. 5/19/2021 29

From any cause related to, or aggravated by the pregnancy or its management § Not from accidental causes 5/19/2021 30

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) 5/19/2021 31

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 5/19/2021 32

• 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. 5/19/2021 33

MMRatio = Total maternal deaths for a period (year) Number of live birth in the same year x 100, 000 Example: The year-end of 1432 H report from the obstetrical ward: 5/19/2021 34

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 MMRatio= 3 2600 x 1, 000 = 1. 15/1000 maternal deaths per 1, 000 live births 5/19/2021 35

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. 5/19/2021 36

Country Maternal mortality rate Per 100, 000 Saudi Arabia 16 Yemen 200 Palestine 32 Iraq 63 Bahrain 20 Emirates 12 Oman 11 Qatar 6 5/19/2021 37

MMRate = Total maternal deaths for a period (year) x 100, 000 Number of women age 15 - 49 Example: The year-end of 1432 H report from the obstetrical ward: 5/19/2021 38

1 - was 10 deaths (2 abortions, 8 pregnancy complications). 2 - The number of women aged 15 -49 was: (250000). MMRate = 10 x 100, 000 250000 = 4/100, 000 5/19/2021 39

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 5/19/2021 40

Example 1: At X city: 1) 110 cases of cancer in 1433 H 2) 29 died in 1433 H. Find CFR: Numerator: # died of cancer = 29 Denominator: Number with cancer = 110 CFR = 29 x 100 110 = 26. 4% 41

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 Total deaths in the same time period 5/19/2021 x 100 42

Example 1: At X city: 1) 10 deaths from cardiovascular disease in 1427 2) 500 deaths from all diseases in 1427 Find PM: PM = 5/19/2021 10 x 100 500 = 2% 43

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). 5/19/2021 44

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. 5/19/2021 45

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. 5/19/2021 46

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. 5/19/2021 47

Country Sex ratio Life expectancy Male Total fertility rate Female Saudi Arabia 105 : 100 71 75 3. 03 Yemen 105 : 100 61 60 5. 48 Palestine 106 : 100 73 77 4. 65 Iraq 105 : 100 70 73 4. 86 Bahrain 103 : 100 76 81 2. 63 Emirates 105 : 100 75 80 2. 36 Oman 105 : 100 75 77 2. 52 Qatar 102 : 100 74 77 1. 92 Jordon 106 : 100 79 82 3. 27 5/19/2021 48

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 5/19/2021 49

• 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. 5/19/2021 50

• 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 = Male death rate at age x x 100 female death rate at age x 5/19/2021 51

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. 5/19/2021 52

Mid year Population Male excess mortality Deaths Males Females Males females 9103 8651 36 12 2. 85 9676 9345 48 15 3. 09 10696 10617 60 21 2. 83 10877 10986 72 27 2. 69 9902 10061 84 33 2. 59 8692 8924 90 45 1. 98 6811 7062 99 57 1. 80 5/19/2021 53

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. 5/19/2021 54

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. 5/19/2021 55

Standardization § A principal role in demography is to compare the mortality between two or more populations. § The comparison of crude mortality rates is misleading. 5/19/2021 56

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. 5/19/2021 57

§ 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. 5/19/2021 58

§ 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. 5/19/2021 59

Methods of Standardization • There are two methods of standardization commonly used: 1 - Direct method 2 - Indirect method). 5/19/2021 60

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). 5/19/2021 62

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. 5/19/2021 63

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. 5/19/2021 64

Population, Deaths, and Death Rate by Community and by Age Community A Age (year) Population Deaths Under 1 1, 000 15 1 – 14 3, 000 15 – 34 Community B Population Deaths 15. 0 5, 000 100 20. 0 3 1. 0 20, 000 35 1. 0 6, 000 6 1. 0 35, 000 35 1. 0 35 – 54 13, 000 52 4. 0 17, 000 85 5. 0 55 – 64 7, 000 105 15. 0 8, 000 160 20. 0 Over 64 20, 000 1, 600 80. 0 15, 000 1, 350 90. 0 All ages 50, 000 1, 781 35. 6 100, 000 1, 740 17. 4 5/19/2021 Death Rate (per 1000) 65

Age (years) Standard population Death rate in A (per 1, 000) Expected deaths at A’s rate Death rate in B (per 1, 000) Expected deaths at B’s rate Under 1 6, 000 15. 0 90 20. 0 1 – 14 23, 000 1. 0 23 0. 5 11. 5 15 – 34 41, 000 1. 0 41. 0 35 – 54 30, 000 4. 0 120 5. 0 150. 0 55 – 64 15, 000 15. 0 225 20. 0 300. 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) 5/19/2021 22. 0 25. 0 66

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 Total standard population 5/19/2021 x 1000

standardized death rate for pop A: 3299 150, 000 x 1000 = 21. 99 per 1000 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. 5/19/2021 68

standardized death rate for pop B: Total standard population = 150, 000 Expected deaths for pop B = 3, 772. 5 5/19/2021 69

Standardized death rate for pop B = Expected deaths pop A Total standard population x 1000 3, 772. 5 x 1000 = 25. 15 per 1000 150, 000 5/19/2021 70

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. 5/19/2021 71

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. 5/19/2021 72

§ 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). 5/19/2021 73

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 5/19/2021 74

This CMR is interpreted as: after controlling for the affects of age, the mortality in Country B is 14% higher than in country A. 5/19/2021 75

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) 5/19/2021 76

• 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. 5/19/2021 77

Table 2. Crude mortality rates stratified by age for two populations (country a, B). Country A Age group 0 - 29 # deaths/ Pop 1000 (M) Country B Death rate # deaths Pop Death rate/ 1000 7, 000 6 1. 2 6, 300 1, 500, 000 4. 2 20, 000 5. 5 3. 6 3, 000 550, 000 5. 5 60+ 120, 000 2. 5 48 6, 000 120, 000 50 Total 147, 000 14 10. 5 15, 300 2, 170, 000 7 30 - 59 78

• 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. 5/19/2021 79

Table 3. Standard population Age group Pop 5/19/2021 0 - 29 100, 000 30 - 59 65, 000 60+ 20, 000 Total 185, 000 80

Age (years) Standard population Death rate in A (per 1, 000) Expected deaths at A’s rate Death rate in B (per 1, 000) Expected deaths at 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 5/19/2021 81

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 Total standard population 5/19/2021 x 1000

standardized death rate for pop A: 1314 185, 000 x 1000 = 7. 1 per 1000 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. 5/19/2021 83

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 Total standard population 5/19/2021 x 1000

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. 5/19/2021 85

We can calculate the Comparative Mortality Ratio (CMR) as: Comparative Mortality Ratio (CMR) = 9. 6/7. 1 = 1. 35 5/19/2021 86

CMR is interpreted as: After controlling for the affects of age, the mortality in Country B is 35% higher than in country A. 5/19/2021 87

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. 5/19/2021 89

• 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. 5/19/2021 90

§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: 5/19/2021 91

Standardized Mortality Ratio(SMR)= Total observed deaths In population (A) __________ Total expected deaths in a population (A) 5/19/2021 92

Age (years) Under 1 1 – 14 15 – 34 35 – 54 55 – 64 Over 64 Total 5/19/2021 Standard death rate pop B (per 1, 000) Total population A Expected deaths in A at standard rates Observed Deaths A 20. 0 1, 000 20. 0 15 0. 5 3, 000 1. 5 3 1. 0 6, 000 6. 0 6 5. 0 13, 000 65. 0 52 20. 0 7, 000 140. 0 105 90. 0 20, 000 1, 800. 0 1, 600 17. 4 50, 000 2, 032. 5 1, 781 93

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. 5/19/2021 94

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. 5/19/2021 95

§ 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 5/19/2021 96

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) 5/19/2021 97

• 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. 5/19/2021 98

Table 2. Crude mortality rates stratified by age for two populations (country a, B). Country A Age group 0 - 29 # deaths/ Pop 1000 (M) Country B Death rate # deaths Pop Death rate/ 1000 7, 000 6 1. 2 6, 300 1, 500, 000 4. 2 20, 000 5. 5 3. 6 3, 000 550, 000 5. 5 60+ 120, 000 2. 5 48 6, 000 120, 000 50 Total 147, 000 14 10. 5 15, 300 2, 170, 000 7 30 - 59 99

• 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. 5/19/2021 100

Table 3. Standard population Age group Pop 5/19/2021 0 - 29 100, 000 30 - 59 65, 000 60+ 20, 000 Total 185, 000 101

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 1, 314 expected deaths Age 1, 134/185, 000 = adjusted 7. 1/1, 000 rate Age standard rate ratio (B : A) = 9. 6/ 5/19/2021 1, 777. 5/185, 000 =9. 6/1000 7. 1 = 1. 35 102

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. 5/19/2021 103

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 30 - 59 60+ 0. 0012 x 1, 500, 000 = 1, 800 0. 0036 x 550, 000 = 1, 980 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 5/19/2021 160 104

• 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. 5/19/2021 105

• 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. 5/19/2021 106

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. 5/19/2021 107

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. 5/19/2021 108