540 likes | 911 Views
Epidemiology. October 21, 2014 II. Morbidity and Mortality. Morbidity תחלואה. הי ארע ות 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
E N D
Epidemiology October 21, 2014 II. Morbidity and Mortality
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
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 10n 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 הימצאותPrevalence 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 x10n 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 Any chronic disease Dyslipidemia Smoking Hypertension Obesity IHD Peptic ulcer Hypothyroid Diabetes Asthma Osteoporosis Cancer Depression
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 SES Family size Farfel et al.Ann Allergy ,Asthma,Imm 2010;104:490-5
שיעור המעשנים בקרב המשתחררים מצה"ל, לפי מין, 2004-1992דוח שר הבריאות על העישון בישראל, ICDC 2005
AIDS-היארעות המחלה, הימצאותה והתמותה ממנה (שיעור ל- 100,000, 1985- 1996)
Routine informationMortality (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 informationתמותת תינוקותInfant mortality rate: Death rate up to one year per 1000 live births Often used as an indicator of “quality” of the health care system
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 = .00018 = .018% 100,000 The case fatality rate from disease “X” = 18 = .9 = 90% 20
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
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-78.96 y Females 83.49 y Health Expenditures: 7.8% of GNP
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
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 20-79 YEARS, 2010)
Prevalence rate of non-insulin-dependent diabetes mellitus in selected populations