《社会医学》PPT课件.ppt

健康状况评价指标,TOPIC,死亡率 潜在寿命损失年-PYLL 伤残调整生命年-DALY 质量调整生命年-QALY 预期寿命-LE 健康预期寿命-HLE,1.Mortality Outcomes,Crude rate: The number of events in a population over a given period of time, usually a calendar year Crude rates reflect the probability of an event As the probability of death increases with age, the crude death rate reflects the age structure of the population,Mortality Outcomes (cont.),Example: 1980,The larger crude death rate in Florida reflects the larger population of elderly in that state.,Calculation Practice,Calculate cause-specific and age-specific lung cancer death rates,What information will you need?,Lung Cancer Deaths by Age Group, United States, 1995,15,420,188,500,741,Total,12,356,31,078,760,45-54,2,709,42,467,719,35-44,303,40,873,139,25-34,41,35,946,635,15-24,11,38,134,488,5-14,Lung Cancer Deaths,Population,Age (years),How would you calculate the cause-specific lung cancer death rate?,How would you calculate age-specific lung cancer death rates?,Lung Cancer Deaths by Age Group, United States, 1995,15,420,xxx,188,500,741,Total,12,356,2,709,303,41,11,Lung Cancer Deaths,12,356 / 31,078,760 = 39.76,2,709 / 42,467,719 = 6.38,303 / 40,873,139 = 0.74,41 / 35,946,635 = 0.11,11 / 38,134,488 = 0.03,Age-Specific Lung Cancer Death Rate,31,078,760,45-54,42,467,719,35-44,40,873,139,25-34,35,946,635,15-24,38,134,488,5-14,Population,Age (years),What inferences can you make from these age-specific rates?,Cause Specific Rate = (15,420/188,500,741) x 100,000 = 8.18 / 100,000,Creating a cause-specific, age-adjusted death rate using direct standardization,(3) x (4) = (5),(4),(1) / (2) = (3),(2),(1),226,500,000,xxx,45,000,115,Total,25,700,000,15,000,100,65+,140,300,000,25,000,10,19-64,60,500,000,5,000,5,0-18,Expected,1980 U.S. Standard Population,Age Specific Rate (per 1000),Population at risk,Cancer Deaths,Age,Creating a cause-specific, age-adjusted death rate using direct standardization,(3) x (4) = (5),(4),(1) / (2) = (3),(2),(1),288,039,000,226,500,000,xxx,45,000,115,Total,171,419,000,25,700,000,6.67,15,000,100,65+,56,120,000,140,300,000,0.40,25,000,10,19-64,60,500,000,60,500,000,1.00,5,000,5,0-18,Expected,1980 U.S. Standard Population,ASR / 1000,Population at risk,Cancer Deaths,Age,Age-Adjusted Rate (288,039,000 / 226,500,000) x 1000 1.27 per 1,000,Crude Rate (115 / 45,000) x 1000 2.56 per 1,000,Comparing crude and age-adjusted rates,If crude rate decreases after adjustment, the study population is older than the standard population (Crude rate age-adjusted rate study population is older) If crude rate increases after adjustment, the study population is younger than the standard population (Crude rate age-adjusted rate study population is younger),2.Potential years of life lost，PYLL,Reference age=75 Age at death=60, PYLL(75)=15 Age at death=0.5, PYLL(75)=74.5 Age at death=80, PYLL(75)=0,1974年加拿大主要疾病死因构成与PYLL构成比较 死亡原因 PYLL(170岁) 死亡(170岁) PYLL(年数) % 死亡例数 % 全部死因 1312675.0 100.0 77440 100.0 交通事故 239238.5 18.2 5864 8.0 缺血性心脏病 198327.5 15.1 19205 26.2 其他事故 165264.5 12.6 4795 6.5 自杀 84195.0 6.4 2716 3.7 消化系统肿瘤 56667.0 4.3 5186 7.1 呼吸系疾病 50264.0 3.8 3425 4.7 呼吸系肿瘤 48079.5 3.7 4444 6.1 脑血管病 45418.0 3.5 4068 5.5 肝硬化 37954.0 2.7 2204 3.0 乳腺癌 30919.0 2.4 2108 2.9 神经系统疾病 29634.0 2.3 1119 1.5 (Frerichs,1986),1974年加拿大主要疾病死因构成与PYLL构成比较 死亡原因 PYLL(170岁) 死亡(170岁) PYLL(年数) % 死亡例数 % 全部死因 1312675.0 100.0 77440 100.0 交通事故 239238.5 18.2 5864 8.0 缺血性心脏病 198327.5 15.1 19205 26.2 其他事故 165264.5 12.6 4795 6.5 自杀 84195.0 6.4 2716 3.7 消化系统肿瘤 56667.0 4.3 5186 7.1 呼吸系疾病 50264.0 3.8 3425 4.7 呼吸系肿瘤 48079.5 3.7 4444 6.1 脑血管病 45418.0 3.5 4068 5.5 肝硬化 37954.0 2.7 2204 3.0 乳腺癌 30919.0 2.4 2108 2.9 神经系统疾病 29634.0 2.3 1119 1.5 (Frerichs,1986),指从发病到死亡所损失的全部健康寿命年，包括因早死所致的寿命损失年 (YLL) 和疾病所致伤残引起的健康寿命损失年 (YLD) 两部分。 DALY=YLL+YLD YLL = N L YLD=IDWL DALY是一个定量计算因各种疾病造成的早死与残疾对健康寿命年损失的综合指标，是测算疾病负担的主要指标之一。据此可确定危害健康严重的疾病和主要卫生问题。,第一节 疾病频率测量,3.伤残调整寿命年 (disability adjusted life year, DALY),WHO model of health transition (1984),What are DALYs?,DALYs = Disability Adjusted Life Years A common measurement unit for morbidity and mortality Facilitates comparisons of all types of health outcomes,CLICK TO ENLARGE,How are DALYs constructed?,A DALY is a health outcome measure with two main components Quality of life reduced due to a disability Lifetime lost due to premature mortality.,DALYs due to living with disability (Red area measures DALYs. Red + white is a “normal” life),82,5 YEARS,NO DISABILITY,DALYs due to early death (Red area measures DALYs. Red + white is a standard life),NO DISABILITY,82,5 YEARS,DALYs due to disability and premature death combined.,NO DISABILITY,82,5 YEARS,Calculation of DALYs (age-weighting and discounting are omitted for didactic reasons),The calculation of DALYs of a woman who has been deaf since she was 5 and dies when she is 50: ( Disability weight of deafness is set at 0.33) : Number of healthy life years the disability weight of full health (0) + life years with disability (50) disabilty weight for deafness (0,33) + life years lost (30) the weighting of death (1) 5 0+ 45 0,33 + 32.5 1 = 47.35 DALYs,4.What is a QALY?,A quality-adjusted life-year (QALY) takes into account both the quantity and quality of life generated by healthcare interventions. It is the arithmetic product of life expectancy and a measure of the quality of the remaining life-years. Q (preferences score) L (life years) = Quality-Adjusted Life Years,Quality-Adjusted Life Years,A,B,0,0.6,0.7,1.0,生命质量,6,9,年,生命数量,A 6年 QoL为0.7 = 4.2QALYs B 9年 QoL为0.6 = 5.4QALYs B - A = 1.2 QALYs,Quality-Adjusted Life Years,Gold, MR et al (Eds.) Cost-effectiveness in Health and Medicine (1996),Q,L,Quality-Adjusted Life Years,A,B,死亡 0,新药干预,无干预,获得的生命 质量年 （QALY）,完全 健康 1.0,生存期,DALYs and QALYs,DALY is a modification of QALY (Quality Adjusted Life Years). Both concepts combine information about length of life and quality of life. A DALY is a negative QALY.,Relation between QALYs and DALYs DALYs = healthy years lost QALYs = healthy years gained,NO DISABILITY,82,5 YEARS,DALYs and QALYs,In the DALY approach, the years are disability weighted on a scale from zero, which indicates perfect health (no disability), to one, which indicates death. In the QALY approach, the scale goes the opposite way: A quality weighting (sometimes called “utility”) of 1 indicates perfect health, whereas 0 indicates no quality of life, and is synonymous to death.,Discounting and Age weighting,Discounting the value of a life year now is set higher than the value of future life years Age weighting life years of children and old people are counted less,Age-weights,Global Burden of Disease age-weighting function,The effect of age-weighs and discounting,Calculating DALY score, with age weighting and discounting.,Girl, 5 years old, with below-knee amputation who lives until she is 82,5: DALYs= life years lived with disease (77,5) disability weight (0,3) age- weight (a1) discounting factor (d2) 77.5 0.3 a1 d2 = 10.5 DALYs,The young,The 5-year-old girl in the example above yielded 10,5 DALYs. However, the DALY score without age-weight and discounting would be 77.5 0.3 = 23,3 DALYs This result is twice as high, and would give her a higher priority.,5.Life Expectancy (LE),The expected number of years to be lived from age x (typically from birth) Measure of population health LE is increasing over time in Asia and around the world,Life expectancy at birth: Selected Asian countries, 1990-2002,World Bank Indicators, 2003,Percent of total population aged 65 years and older, 1990-2002,World Bank Indicators, 2003,6.Healthy life expectancy (HLE),The expected number of years to be spent in good health from age x “Health” usually refers to functional abilities or self-rated health Advantage of HLE: ease in interpretation LE 65 = 20.9 yrs*; HLE 65 = 18.3 yrs* % of LE in good health: HLE/LE = .88 *Females in Japan, 1995,Estimating healthy life expectancy using the Sullivan (1971) method and life tables:,DPR = Disability prevalence rate for age x from survey data Lx(hs) = (1 - DPR) * Lx person years spent in health Tx(hs) = x=t L x(hs) + t total person years lived in health ex(hs) = Tx(hs) / lx healthy life expectancy Note: hs=healthy state,LE at birth and age 65 (UK), 2.6 years men 1.7 years women, 2.0 years men 1.2 years women,LE at birth (Europe),Life Expectancy at birth,World Health Report 2006,Life Expectancy (LE) and Healthy Life Expectancy (HLE), China, 1987,Females are advantaged with more years of life and more years of healthy life.,Grab et al., 1991,Similar trends in other Asian countries:,Life Expectancy 65,Healthy Life Expect