PHRM 100 (2024/2025): Foundations of Pharmacy Lecture PDF

PHRM 100 (2024/2025) Foundations of Pharmacy Pharmacist, Patient, and Health Care Systems Lecture 7 Evidence Evaluation Epidemiology: How do we measure disease? October 22, 2024 UBC Faculty of Pharmaceutical Sciences...

PHRM 100 (2024/2025) Foundations of Pharmacy Pharmacist, Patient, and Health Care Systems Lecture 7 Evidence Evaluation Epidemiology: How do we measure disease? October 22, 2024 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 1 Module Lecture Material Prepared by Dr. Mary De Vera Land Acknowledgement UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 2 Module Lecture Material Prepared by Dr. Mary De Vera Learning Objectives To discuss what epidemiology is To know the assumptions of epidemiology To know the three types of epidemiology Descriptive, analytic, experimental To describe and calculate measures of disease occurrence Rank, count, ratio (proportion, rates) To define & differentiate between prevalence and incidence of disease Distinguish between incident cases versus prevalent cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 3 Module Lecture Material Prepared by Dr. Mary De Vera Learning Objectives To discuss what epidemiology is To know the assumptions of epidemiology To know the three types of epidemiology Descriptive, analytic, experimental To describe and calculate measures of disease occurrence Rank, count, ratio (proportion, rates) To define & differentiate between prevalence and incidence of disease Distinguish between incident cases versus prevalent cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 4 Module Lecture Material Prepared by Dr. Mary De Vera Resource (PDF in CANVAS) Bonita. Basic Epidemiology 2 nd Edition. World Health Organization. 2006. (Not required reading and not examinable; Provided as a resource for those interested in additional reading/learning on epidemiology as well as a reference for future use) UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 5 Module Lecture Material Prepared by Dr. Mary De Vera epidemiology upon demos - people logos – study of UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 6 Module Lecture Material Prepared by Dr. Mary De Vera What is epidemiology Science of distribution and frequency of disease Distribution of disease Person Place Time Frequency of disease Incidence Prevalence UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 7 Module Lecture Material Prepared by Dr. Mary De Vera person place time November 2020 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 8 Module Lecture Material Prepared by Dr. Mary De Vera What can epidemiology do? Describe health of a population Explain cause of disease Predict occurrence of disease Control distribution of disease UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 9 Module Lecture Material Prepared by Dr. Mary De Vera History of epidemiology Traced source of 1854 cholera outbreak in England to Broad Street pump UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 10 Module Lecture Material Prepared by Dr. Mary De Vera Assumptions of epidemiology 1. Disease does not occur randomly 2. Disease has causal and preventative factors that we can identify through systematic investigation of different people at different places or times UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 11 Module Lecture Material Prepared by Dr. Mary De Vera Three types of epidemiology and goals To examine patterns (of disease, Descriptive Goal health behaviors) Analytic Goal To evaluate relationships between risk/protective factors and disease To evaluate effect of Experimental Goal treatment/intervention on disease UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 12 Module Lecture Material Prepared by Dr. Mary De Vera Learning Objectives To discuss what epidemiology is To know the assumptions of epidemiology To know the three types of epidemiology Descriptive, analytic, experimental To describe and calculate measures of disease occurrence Rank, count, ratio (proportion, rates) To define & differentiate between prevalence and incidence of disease Distinguish between incident cases versus prevalent cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 13 Module Lecture Material Prepared by Dr. Mary De Vera Types of measures of disease occurrence Rank Count(s) Key consideration who, what is in numerator and/or Ratio denominator When you hear/see measure(s) in news/internet, Proportion ask yourself what type of measure is it? Rate UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 14 Module Lecture Material Prepared by Dr. Mary De Vera UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 15 Module Lecture Material Prepared by Dr. Mary De Vera Rank Example Measures the order of disease occurrence Other example(s) rank Arthritis and other rheumatic conditions are the leading cause of work disability among US adults Diabetes is the 7th leading cause of death in the US UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 16 Module Lecture Material Prepared by Dr. Mary De Vera Count(s) Example Measure(s) the number of persons who have a given disease No denominator Other example(s) Number of female(s) with disease X (red) count UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 17 Module Lecture Material Prepared by Dr. Mary De Vera Ratio Example The quotient of two numbers Family doctors in BC Numerator not necessarily included in denominator (no specific relationship between numerator and 2022: 270 family doctors denominator) 100,000 British Columbians Allows comparison of quantities of different nature Other example(s) Male to female ratio UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 18 Module Lecture Material Prepared by Dr. Mary De Vera Ratio (preview) Measures of association in epidemiologic studies are ratios Relative risk (RR) (or Rate ratio or Risk ratio) Odds ratio (OR) More in Lecs 8, 9, 13 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 19 Module Lecture Material Prepared by Dr. Mary De Vera  Example Proportion The quotient of two numbers Numerator is necessarily included in the denominator Expressed as a: fraction (1/5) or proportion decimal (e.g., 0.2) or percentage (20%) UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 20 Module Lecture Material Prepared by Dr. Mary De Vera Rate Example The quotient of two numbers observed in 2020 Numerator Number of ‘events’ (new cases of disease) observed for a given time Denominator 1 = 0.1 per year 10 Population in which events occur Includes time UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 21 Module Lecture Material Prepared by Dr. Mary De Vera Rate Example 5-year cancer survival rate Ratio of people who are alive for 5 years after cancer diagnosis to people in the general population who are alive over the same 5 year period UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 22 Module Lecture Material Prepared by Dr. Mary De Vera Learning Objectives To discuss what epidemiology is To know the assumptions of epidemiology To know the three types of epidemiology Descriptive, analytic, experimental To describe and calculate measures of disease occurrence Rank, count, ratio (proportion, rates) To define & differentiate between prevalence and incidence of disease Distinguish between incident cases versus prevalent cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 23 Module Lecture Material Prepared by Dr. Mary De Vera Prevalence versus incidence Prevalence All individuals affected by disease at a particular time Refer to individuals as “prevalent cases” or “active cases” Incidence New individuals with a disease during a particular period of time Refer to individuals as “incident cases” or “new cases” UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 24 Module Lecture Material Prepared by Dr. Mary De Vera  incident prevalent cases cases November 2020 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 25 Module Lecture Material Prepared by Dr. Mary De Vera Prevalence (a proportion) Definition: Proportion of a population affected by a disease at a specific time Prevalence = Number of individuals with disease at specific time Number of individuals in population *Usually expressed as a percentage UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 26 Module Lecture Material Prepared by Dr. Mary De Vera Prevalence (a proportion) Example: In city X which has a population of 350,000, there were 45,000 individuals with type 2 diabetes on December 31, 2020. What is the prevalence of type 2 diabetes? UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 27 Module Lecture Material Prepared by Dr. Mary De Vera Point and period prevalence Point prevalence: Proportion of a population affected by a disease at a point in time (e.g., prevalence of type 2 diabetes on December 31, 2020) Period prevalence: Proportion of a population affected by a disease during a certain period of time (e.g., prevalence of diabetes in 2020) UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC Module Lecture Material Prepared by Dr. Mary De Vera 28 (Please do not distribute outside of course) Incidence Definition: The number of new cases of a disease that develop over time UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 29 Module Lecture Material Prepared by Dr. Mary De Vera Incidence proportion (cumulative incidence) Incidence proportion= Number of new cases of disease over period of time Number of individuals at risk for disease at beginning of time period UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 30 Module Lecture Material Prepared by Dr. Mary De Vera Incidence proportion (cumulative incidence) Incidence proportion= Number of new cases of disease over period of time Number of individuals at risk for disease at beginning of time period 0 years 5 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 31 Module Lecture Material Prepared by Dr. Mary De Vera Incidence proportion (cumulative incidence) Incidence proportion= Number of new cases of disease over period of time Number of individuals at risk for disease at beginning of time period Incidence proportion = 4 / 10 = 0.40 At Home Review: = 40% (expressed as percentage) OR Work through to = 4 cases per 10 population during 5 year period show that these = 0.8 cases per 10 population per year are equivalent = 8 cases per 100 per year 0 years 5 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 32 Module Lecture Material Prepared by Dr. Mary De Vera Incidence rate (incidence density) Incidence rate = Number of new cases of disease over period of time 𝚺 person-time UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 33 Module Lecture Material Prepared by Dr. Mary De Vera Incidence rate: “Person-time” Time each person was observed Consider: 1 person at risk of a disease observed for 1 year = 1 person-year 1 person at risk of a disease observed for 1 month = 1 person-month Can be presented in many different ways: 10 cases per 1000 person-years 1 case per 100 person-years 0.1 cases per 10 person-years 0.01 cases per 1 person-year UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 34 Module Lecture Material Prepared by Dr. Mary De Vera Incidence rate: “Person-time” Time each person was observed Consider: 1 person at risk of a disease observed for 1 year = 1 person-year 1 person at risk of a disease observed for 1 month = 1 person-month Can be presented in many different ways: 10 cases per 1000 person-years 1 case per 100 person-years These are all the same! 0.1 cases per 10 person-years 0.01 cases per 1 person-year At Home Review: Work through to prove this is true UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 35 Module Lecture Material Prepared by Dr. Mary De Vera Incidence rate Incidence rate = Number of new cases of disease over period of time 𝚺 person-time 0 years 5 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 36 Module Lecture Material Prepared by Dr. Mary De Vera Incidence rate Incidence rate = Number of new cases of disease over period of time 𝚺 person-time 5 person-years 5 person-years 2 person-years 5 person-years Incidence rate = 4 / 43 person-years 5 person-years = 0.093 person-years 4 person-years = 9.3 per 100 person-years 5 person-years 5 person-years 2 person-years 5 person-years 0 years 5 UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 37 Module Lecture Material Prepared by Dr. Mary De Vera Incidence proportion vs Incidence rate Numerator: New cases Numerator: New cases Denominator: Number of individuals Denominator: Person-time at beginning of period Incorporates time directly into Time period specified but not denominator included in calculation UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 38 Module Lecture Material Prepared by Dr. Mary De Vera Prevalent and incident cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 39 Module Lecture Material Prepared by Dr. Mary De Vera Figure 7.7 Births Recoveries Population reservoir Immigration Incident cases Emigrant cases, Prevalent cases unmeasured cases occurring abroad, and deaths Emigrant and non- Recoveries measured cases, deaths UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC Module Lecture Material Prepared by Dr. Mary De Vera Prevalence and Incidence Prevalence “Disease Burden” Incidence “Disease Risk” Measure population disease status Assess frequency of disease onset Help plan health care delivery Estimate risk of disease development Indicate groups who should be targeted Study risk factors for disease Evaluate preventive interventions UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 41 Module Lecture Material Prepared by Dr. Mary De Vera Learning Objectives To discuss what epidemiology is To know the assumptions of epidemiology To know the three types of epidemiology Descriptive, analytic, experimental To describe and calculate measures of disease occurrence Rank, count, ratio (proportion, rates) To define & differentiate between prevalence and incidence of disease Distinguish between incident cases versus prevalent cases UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 42 Module Lecture Material Prepared by Dr. Mary De Vera Sample question: Incidence or prevalence? Nearly 60% of people with arthritis in Canada are women Every year, the number of individuals in the United States and northern European who are newly diagnosed with rheumatoid arthritis is estimated to be approximately 40 per 100,000 persons By 2040, about 24% Canadians will be diagnosed with arthritis In Canada, nearly 1 in 2 seniors over 65 have arthritis UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC Module Lecture Material Prepared by Dr. Mary De Vera Sample question: Incidence or prevalence? Nearly 60% of people with arthritis in Canada are women Prevalence Every year, the number of individuals in the United States Incidence and northern European who are newly diagnosed with rheumatoid arthritis is estimated to be approximately 40 per 100,000 persons By 2040, about 24% Canadians will be diagnosed with Incidence arthritis In Canada, nearly 1 in 2 seniors over 65 have arthritis Prevalence UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC Module Lecture Material Prepared by Dr. Mary De Vera Sample question: According to The Arthritis Society, nearly 60% of people with arthritis in Canada are women. What type of measure of disease occurrence does this represent? A. Rank B. Rate C. Proportion D. Ratio UBC Faculty of Pharmaceutical Sciences PHRM 100 PPHC 45 Module Lecture Material Prepared by Dr. Mary De Vera