Lecture Note 6 BME 421 on measurement_of_morbidity_and_mortality.pptx

Health Management information system

1. EPIDEMIOLOGY Measurement of morbidity and Mortality Lecture Note 6 BME 421 Health Management and Information System Engr . Ocheri C. 24/09/1446 1

2. Learning objectives State three mathematical terms used in epidemiology Differentiate between incidence and prevalence State one epidemiologic measure of morbidly and mortality Define the term specific rate Epidemiologic Measurements Used to Describe Disease Occurrence 3/23/2025 2

3. Epidemiologic Measurements Used to Describe Disease Occurrence Measures of disease frequency in mathematical quantity Count Proportion (percentage) Rate Ratio Measures of disease frequency in epidemiology Prevalence Incidence

4. Epidemiologic Measurements Used to Describe Disease Occurrence Importance of Denominator a Numerator b Denominator Example • 500 cases of dengue fever in Jeddah • 120 cases of dengue fever in Abha Which one is more infected? • Jeddah: 500/2,000,000 = 0.25/1,000 • Abha: 120/300,000 = 0.4/1,000

5. Epidemiologic Measurements Used to Describe Disease Occurrence Counts : Simplest & most basic measure – absolute number of persons who have disease or characteristic of interest. Useful for health planners & administrators: for allocation of resources (e.g. quantity of beds needed by a community) Count of No. cases of a disease, is used for surveillance of infectious disease for early detection of outbreaks .

6. FREQUINCY MEASURES RATES , RATIOS , AND PROPORTINS In epidemiology, the most important tool for measuring disease is the rate , but we also use ratios and proportions . A ratio expresses the relationship between two numbers in the form x : y or x/y MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 6

7. FREQUINCY MEASURES In a ratio the value of a variable, such as sex ( x = female, y = male), may be expressed so that x and y are completely independent of each other, or x may be included in y   Female/male or x/y   MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 7

8. FREQUINCY MEASURES A proportion is a specific type of ratio, in which x is a portion of the whole, x + y , in a proportion the numerator is always included in the denominator.   Female /(male + female) or x/ ( x + y ) MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 8 X X + Y

9. FREQUINCY MEASURES RATES , RATIOS , AND PROPORTINS In epidemiology, the occurrence of a disease or condition can be measured using rates and proportions. We use these measures to express the extent of these outcomes in a community or other population. Rates tell us how fast the disease is occurring in a population . Proportions tell us what fraction of the population is affected . MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 9

10. FREQUINCY MEASURES A rate is a special form of proportion that includes specification of time. In health care rates are often used to measure an event over time. MEASUREMENT OF MORBIDITY AND MORTALITY Number of cases or events in a specified period x k Number of cases or population at risk during the same period 3/23/2025 10

11. POPUALTION BASED MORTALITY MEASURES Crude Death Rate The crude death rate is a measure of the actual observed mortality in a given population . Summary rate of the actual number of observed events in a population over a given time period (e.g. all cancer deaths in 2000) MEASUREMENT OF MORBIDITY AND MORTALITY Crude Death Rate = Number of deaths* X 1000 Estimated midinterval population** 3/23/2025 11

12. POPUALTION BASED MORTALITY MEASURES Specific Rate Rates for specific segments/groups of the population (e.g. sex, age, race, cause of death, cancer site ) . MEASUREMENT OF MORBIDITY AND MORTALITY Age-specific death rate =   Number of deaths of a specified age group* X 1000 Estimated midinterval population of that age group** 3/23/2025 12

13. POPUALTION BASED MORTALITY MEASURES Specific Rate Rates for specific segments/groups of the population (e.g. sex, age, race, cause of death, cancer site ) . MEASUREMENT OF MORBIDITY AND MORTALITY Cause Specific Death Rate = Total number of deaths due to a specific cause during a given time interval* X 1000 Estimated midinterval population** 3/23/2025 13

14. POPUALTION BASED MORTALITY MEASURES Specific Rate Rates for specific segments/groups of the population (e.g. sex, age, race, cause of death, cancer site ) . Adjusted rate: Used to compare rates for entire populations, taking into account differences in variables we consider as influencing outcomes (age, gender, race ) MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 14

15. POPUALTION BASED MORTALITY MEASURES Two methods to adjust rates: Direct Method: AAR (age-adjusted rate ) Indirect Method: SMR (standardized mortality ratio) MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 15

16. POPUALTION BASED MORTALITY MEASURES MEASUREMENT OF MORBIDITY AND MORTALITY Proportionate Mortality Ratio = Total number of deaths due to a specific cause during a given time interval* X 1000   Total number of deaths from all causes during the same time interval 3/23/2025 16

17. POPUALTION BASED MORTALITY MEASURES Birth rate is the number of live births in a geographic area in a defined period,  usually one year, relative to some specific population. For the crude birth rate, it is the average total population or the midyear population in the area during the period. MEASUREMENT OF MORBIDITY AND MORTALITY Crude Birth Rate = Number of live births* X 1000   Estimated midinterval population** 3/23/2025 17

18. POPUALTION BASED MORTALITY MEASURES Fertility rate  is the number of children a woman would give birth to in her lifetime based on the current age-specific live birth rate MEASUREMENT OF MORBIDITY AND MORTALITY Fertility Rate = Number of live births* X 1000 Estimated number of females aged 15-44 (WHO uses 10-49) at midinterval ** 3/23/2025 18

19. POPUALTION BASED MORTALITY MEASURES Fertility rate  is the number of children a woman would give birth to in her lifetime based on the current age-specific live birth rate MEASUREMENT OF MORBIDITY AND MORTALITY Fertility Rate = Number of live births* X 1000 Estimated number of females aged 15-44 (WHO uses 10-49) at midinterval ** 3/23/2025 19

20. POPUALTION BASED MORTALITY MEASURES Cause Fatality Rate MEASUREMENT OF MORBIDITY AND MORTALITY Cause Fatality Rate =   Total number of deaths assigned to a specific disease during a given time interval* X 100 Total number of cases of the disease during the same time interval 3/23/2025 20

21. POPUALTION BASED MORTALITY MEASURES Neonatal Mortality Rate MEASUREMENT OF MORBIDITY AND MORTALITY Neonatal Mortality Rate = Number of deaths under 28 days during a given time interval* X 100 Number of live births during the same time interval 3/23/2025 21

22. POPUALTION BASED MORTALITY MEASURES Post neonatal Mortality Rate MEASUREMENT OF MORBIDITY AND MORTALITY Post neonatal Mortality Rate = Number of deaths from 28 days up to and not including one year of age during a given time interval X 100 Number of live births during the same time interval less neonatal deaths 3/23/2025 22

23. POPUALTION BASED MORTALITY MEASURES Infant Mortality Rate MEASUREMENT OF MORBIDITY AND MORTALITY Infant Mortality Rate = Number of deaths under one year of age during a given time interval X 1000 Number of live births during the same time interval 3/23/2025 23

24. POPUALTION BASED MORTALITY MEASURES Maternal Mortality Rate MEASUREMENT OF MORBIDITY AND MORTALITY Maternal Mortality Rate = Number of deaths assigned to pregnancy related causes during a given time interval* X 100 Number of live births during the same time interval 3/23/2025 24

25. FREQUENTLY USED MEASURES OF MORBIDITY   Incidence Rate The incidence rate is the commonly used measure for comparing frequency of a disease in populations. MEASUREMENT OF MORBIDITY AND MORTALITY Incidence Rate = Total number of new cases of a specific disease during a given time interval* X 100 Total population at risk during the same time interval 3/23/2025 25

26. FREQUENTLY USED MEASURES OF MORBIDITY   Prevalence Rate The prevalence rate is the proportion of persons in a population that have a particular disease at a specific point in time or over a specific period of time . MEASUREMENT OF MORBIDITY AND MORTALITY Prevalence Rate = All new and preexisting cases of a specific disease during a given time interval* X 100 Total population at risk during the same time interval 3/23/2025 26

27. MEASUREMENT SCALE TYPES Nominal scales are the lowest level of measurement where the measurement of a variable involves the naming or categorization of a possible value of the variable, example sex male and female, nationality Saudi, non-Saudi . MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 27

28. MEASUREMENT SCALE TYPES Ordinal scales the next level involves rank ordering values of variables. The number assigned to an ordinal scale signify order or rank, examples of ordinal scales are Likert scale or severity of condition, or degrees of burns . MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 28

29. MEASUREMENT SCALE TYPES Interval scales these scales enables the identification of equal intervals between any two values of measurements, however, there is no absolute zero point, rather an arbitrary zero point is assigned, example heat (Celsius or Fahrenheit) intelligence (IQ) . MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 29

30. MEASUREMENT SCALE TYPES Ratio scales is the highest scale of measurement, in that it involves all of the characteristics of the other scales as well as having an absolute zero, example of ratio scales weight or height of a person, blood pressure or heart beats . A measurement on a higher scale can be converted or transformed to into one on lower level, but not vice versa. MEASUREMENT OF MORBIDITY AND MORTALITY 3/23/2025 30

31. http://www.who.int/gho/publications/world_health_statistics/en / World Health Statistics WHO's annual World Health Statistics reports present the most recent health statistics for the WHO Member States. 3/23/2025 31