Epidemiology October 21, 2014 II. Morbidity and Mortality

Measuring health and disease Definitions 2. Measures of disease frequency היארעות, הימצאות, שיעורי תמותה, תוחלת חיים 3. Routinely available information (e.g., mortality, morbidity), time trends 4. Health in Israel

Morbidity תחלואה

היארעות Incidence Incidence per 1,000 = no. of new cases of disease occurring in the population during a specified period of time x1000 no. of persons at risk of developing the disease during that period of time

Annual age-specific incidence rates of reported cases of breast cancer, by marital status

Cumulative incidence CI = number of people who develop disease during a certain period number of individuals in the population at the beginning of the period

Cumulative incidence

Incidence rate measures: The rate at which new events occur in a population. Incidence rate/density is calculated by: Number of persons who contract the disease in a specified period x 10 n Sum of the length of time each person in the population at risk of contracting the disease (person-time incidence)

Example of calculation of disease occurrence

Simple incidence: 3 cases in 7 individuals over 7 year Yearly incidence: 3/7/7=0.06 cases per year (6%/yr) Incidence density: 3/33 p.yr=0.09 cases per p.yr (9 per 100 p.y)

Cumulative incidence Is a simpler measure of the occurrence of a disease or new health status. Unlike incidence rate, it measures the denominator at only one point in time.

Prevalence הימצאות Prevalence rate is defined as: The proportion of the population at risk affected by a disease at a specific point in time Prevalence rate (P) is calculated by: P= number of people with disease or condition at a specific time x10 n number of people in the population at risk at the specified time

מחלות נבחרות - שיעור הימצאותן של מחלות ממושכות, ל- 100 מבוטחים על פי הרישום בתיקי הרופאים בקופת חולים הכללית, 1996

Random Sample of 1740 members of Clalit who visited their doctors at least three times in 2009 Dyslipidemia Any chronic disease Diabetes Hypertension Smoking IHD Osteoporosis Cancer Asthma Hypothyroid Peptic ulcer Depression Obesity

Israel – Results of social survey 2004 prevalence of:

Prevalence of asthma among 17 year olds in Israel Study population 159,243 consecutive 17-year-old military recruits Asthma was documented in 8.5% of the male recruits and in 6.7% of the female recruits Farfel et al.Ann Allergy,Asthma,Imm 2010;104:490-5 SES Family size

Prevalence of obesity, OECD, 2011

שיעור המעשנים בקרב המשתחררים מצה"ל, לפי מין, דוח שר הבריאות על העישון בישראל, ICDC 2005

Factors influencing observed prevalence rate

Relationship between incidence and prevalence: I

Relationship between incidence and prevalence: II

Relationship between incidence and prevalence: IV

AIDS-היארעות המחלה, הימצאותה והתמותה ממנה (שיעור ל- 100,000, )

Mortality תמותה

Routine information Mortality (death) data: (coded according to the ICD) Crude mortality rate (CMR) CMR= total # people dying total # people Age-specific rates Sex-specific rates Cause-specific rates Age-standardized rates (also called age- adjusted rates)

Routine information תמותת תינוקות Infant mortality rate: Death rate up to one year per 1000 live births Often used as an indicator of “quality” of the health care system

תמותת תינוקות, ישראל

Case fatality rate Case fatality rate (percent) = no. of individuals dying during a specified period of time after disease onset or diagnosis x 100 no. of individuals with the specified disease

Comparison of a mortality rate and case-fatality rate Assume a population of 100,000 people of whom 20 are sick with disease “X” and in 1 year, 18 die from disease “X” The mortality rate in that year from disease “X” = 18 = =.018% 100,000 The case fatality rate from disease “X” = 18 =.9 = 90% 20

Relationship between incidence and mortality CFR

Case Fatality Ebola Variation by time and place

Gap between incidence and mortality rates may reflect case fatality

Definition:Life expectancy at birth and ages 40, 60, 65 and 80 is the average number of years that a person at that age can be expected to live, assuming that age-specific mortality levels remain constant תוחלת החיים

Life expectancy

Israel Health Stats Obesity (adult prevalence 2008) 26.2% Maternal Mortality Rate: 7/100,000 live births Infant Mortality: 4.03/1000 Life expectancy at birth: Males y Females y Health Expenditures: 7.8% of GNP

Trends over time

Gender Gap Life Expectancy at birth

Quantifying Burden YLL = Years of Life Lost YLD = Years of Life lived with specified level of Disability (0,1) DALY: Disability Adjusted Life Year: = 1 year lost of healthy life DALY = YLL + YLD

Health statistics are used for other purposes

Sources of Israeli data Central Bureau of Statistics למ"ס המרכז הלאומי לבקרת מחלות Research institutions (Brookdale) Academia

One last point Age matters!

Prevalence of diabetes rate per 100,000 persons- International comparison

Importance & Relevance DIABETES Prevalence Worldwide (OECD INDICATORS, ADULTS YEARS, 2010)

Prevalence rate of non-insulin- dependent diabetes mellitus in selected populations