Причины смерти и методы их анализа

1. Причины смерти и методы их анализа Н.С. Гаврилова

2. Causes of death and their classification • Established by the World Health Organization as International Classification of Diseases (ICD) • Has several revisions. The most recent revision is the 10th revision. Adopted by most countries in the mid 1990s

3. Classification of causes of death in Russia • Classification of causes of death used in the Soviet statistical forms was different from WHO classification. • Form #5 (later called form C51) had 185 causes of death. • Main differences between WHO and Soviet classification are found in the groups of CVD and injuries

5. New classification of causes of death in Russia • After dissolution of the Soviet Union most FSU countries continued to use the old classification of causes of death • In 1999 Russia adopted a new classification of causes of death corresponding to the 10th ICD revision • Still incompatible with the WHO classification

6. Selected Causes of Death

7. Major causes of death within the group of injuries. Men Иванова и др., Demoscope Weekly, N181-182, 2004

8. Major causes of death within the group of injuries. Women Иванова и др., Demoscope Weekly, N181-182, 2004

9. Degradation of mortality statistics in Russia

10. Pace of Growth of Age-Adjusted Mortality in 1989-2000 for Classes of Causes of Death

11. Proportion of deaths from ill-defined conditions is a measure of quality of mortality statisticsProportion higher than 5% indicates poor qualityIn developed countries most deaths from ill-defined conditions are diagnosed at older ages

12. Is this increase in mortality from ill-defined conditions related to more cases of deaths from senility?

13. Age Profile of Mortality from Ill-Defined Conditions in Russia Males Females

14. Top Five Causes of Death for Young Adult Males (20-24)

15. Top Five Causes of Death for Young Adult Females (20-24)

16. Which Causes of Death Are Hidden Behind the Ill-Defined Conditions?

17. We Used Individual Death Certificates With More Detailed Description of Circumstances of Death Collected by Kirov Department of HealthKirov is a Typical Russian Region with Lower than Average Mortality from Ill-Defined Conditions

18. Age-Adjusted Mortality from Injuries in 1996 for Russian Males Aged 0-64 yearsData from the WebAtlas Project (http://sci.aha.ru/ATL)

19. Deaths from Ill-Defined Conditions in Kirov Region of Russia in 2003 • Sudden infant death (R95) 3.3% • Decomposition in water (river, well, pond) (R99) 13.0% • Decomposition at home (R99) 53.5% • Decomposition in garden, summer house (R99) 1.7% • Decomposition in forest or field (R99) 6.0% • Decomposition in nonresidential building, on the street (R99) 12.3% • Decomposition in water pipe (R99) 0.7% • Decomposition on the cemetery (R99) 0.3% • Decomposition in bath, lavatory or barn (R99) 1.0% • Decomposition in other place (R99) 5.5% • unknown (R99) 2.3% • senility (R54) 0.3%

20. Ill-defined conditions and external deaths of undetermined intent are two sides of the same coinIt appears that both causes of death may be used for concealing criminal cases of violent death

21. Mortality in Moscow city

22. Top Five Causes of External Mortality in Russia and Moscow in 2001

23. Autopsies in Russia • Autopsies are used to verify cause of death • Autopsy is mandatory for violent death, death of woman during pregnancy, labor or postpartum period, death of infant below 1 year, death from cancer not supported morphologically, death from any infectious disease

24. Situation with medical examiner services • Only 34-48% of jobs are filled by physicians • 38-54% of jobs are filled by histologists • 35% of workers reached retirement age

25. Additional reading Gavrilova N.S., Semyonova V.G., Dubrovina E., Evdokushkina G.N., Ivanova A.E., Gavrilov L.A. Russian Mortality Crisis and the Quality of Vital Statistics. Population Research and Policy Review, 2008, 27: 551-574.

26. Measures of Mortality • Crude Death Rate • Age-Specific Death Rates (Age-Specific Mortality Rates) • Age-Adjusted Mortality Rates (Standardized Mortality Rates) • Life Expectancy (at birth or other age) • Measures of Infant Mortality

27. Crude Death Rate • Number of deaths in a population during a specified time period, divided by the population size "at risk" of dying during that study period. • For one-year period, Crude Death Rate, CDR  = Deaths in that year /mid-year population size x 1,000  to adjust for standard-sized population of 1,000 persons mid-year population = total population for July 1

28. Crude Death Rate Pros and Cons • Pros: - Easy to calculate, and require less detailed data than other mortality measures - Useful for calculation of the rate of natural increase (crude birth rate minus crude death rate) • Cons: - Depends on population age structure (proportions of younger and older people)

29. Trends in crude death rates (per 1,000) for Russia, USA and Estonia

30. Distribution of crude death rates (per 1,000) in Russia, 2003

31. Age-Specific Death Rates (ASDR) or Age-Specific Mortality Rates (ASMR) • Number of deaths in a specific age group during a specified time period, divided by the size of this specific age group during that study period. Example: For one-year study period, Age-Specific Death Rates, ASDR for males at age 45-49 years  = =  Deaths to males aged 45-49 in that year / Number of males aged 45-49 at mid-year x 1,000  to adjust for standard-sized population of 1,000 persons of that age.

32. Age-Specific Death Rates Pros and Cons • Pros: - Allows to study mortality by age (and sex) • Cons: - Requires detailed data on deaths by age (not always available for developing countries, war and crisis periods, historical studies)

33. Infant Mortality Rate, IMR • Proportion of infants who die in their first year Number of deaths under age one during a specified time period, divided by the number of live births For one-year period, Infant Mortality Rate x 1,000  to standardize per 1,000 live births

34. Infant Mortality Rate Pros and Cons • Pros: - Sensitive indicator of overall health conditions in a country, particularly child health - Useful for indirect estimates of mortality in other age groups through imputation, using the so-called "model life tables" • Cons: - Requires accurate data on births and infant deaths (not always available for developing countries, war and crisis periods, historical studies)

35. Changes in infant mortality in Russia, USA and Estonia

36. Definition of live birth in the USSR was not consistent with WHO definition • WHO definition of live birth: "the complete expulsion or extraction from its mother of a product of conception, irrespective of the duration of pregnancy which, after such separation, breathes or shows any other evidence of life, such as beating of the heart, pulsation of the umbilical cord or definitive movement of voluntary muscles, whether or not the umbilical cord has been cut or the placenta is attached.“ • The Soviet Union adopted a less inclusive definition, excluding infants born before 28 weeks and those weighing less than 1000 grams, regardless of signs of life. • Soviet definition resulted in underestimation of infant mortality • After getting independence, many FSU countries adopted WHO definition of live birth

37. Distribution of infant mortality in Russian regions, 2003

38. Стандартизованные показатели • Стандартизованный коэффициент (прямой метод) • Стандартизованное отношение смертности • Потенциальные годы потерянной жизни

39. Age-adjusted death rate (ADR), standardized death rate (SDR) or age-standardized death rate (ASDR) • Death rate expected if the studied population had the age distribution of another "standard" population (arbitrary chosen for the purpose of comparison). Calculated as weighted average  (with weights being proportions of the "standard" population at each age)

40. Age-Adjusted Death Rate or Age-Standardized Death Rate • Direct method of age standardization: • Mui is mortality rate in the studied population at age i • Psi – number of persons at age i in the standard population. Ps – total standard population.

41. Age-Adjusted Death Rate or Age-Standardized Death Rate • Pros: - Allows comparison of death rates of populations despite differences in their age distribution • Cons: - Requires data on death rates by age (not always available for developing countries, war and crisis periods, historical studies) - Results of comparison may depend on the arbitrary choice of standard.

42. Стандартизованное отношение смертности или Standardized mortality ratio где Du - суммарное число умерших в изучаемой популяции, Msi - коэффициент смертности в стандартной популяции в возрастной группе i, Pui - численность населения в возрастной группе i для изучаемой популяции

43. Стандартизованное отношение смертности • Полезно использовать для маленьких регионов и редких причин смерти • За стандартное распределение обычно выбирается распределение смертей по всей стране

44. Потенциальные годы потерянной жизни Potential Years of Life Lost (PYLL) где T - верхний предельный возраст, до которого рассчитывается недожитие (обычно 70 или 65 лет), x - середина соответствующего возрастного интервала. Потерянные годы потенциальной жизни рассчитываются как сумма произведений числа умерших на недожитые годы в каждой возрастной группе Коэффициент потерянных лет потенциальной жизни рассчитывается соответственно: RatePYLL = PYLL/Pu где Pu - численность изучаемого населения в возрасте от 1 до T.

45. The Concept of Life Table • Life table is a classic demographic format of describing a population's mortality experience with age. Life Table is built of a number of standard numerical columns representing various indicators of mortality and survival. The concept of life table was first suggested in 1662 by John Graunt. Before the 17th century, death was believed to be a magical or sacred phenomenon that could not and should not be quantified.  The invention of life table was a scientific breakthrough in mortality studies.

46. Life Table • Cohort life table as a simple example • Consider survival in the cohort of fruit flies born in the same time

47. Number of dying, d(x)

48. Number of survivors, l(x)

49. Number of survivors at the beginning of the next age interval: l(x+1) = l(x) – d(x) Probability of death in the age interval: q(x) = d(x)/l(x)

50. Probability of death, q(x)