Mortality measurements | Anatomy2Medicine

Mortality measurements

  • Survival rate can be used as a yardstick for the assessment of standards of therapy –
  • Survival rate: Is the proportion of survivors in a group (e.g. of patients), studied and followed over a period of time (e.g. over a period of 5 years)
  • Is used to ‘describe prognosis’ in certain disease conditions
  • Can be used as a ‘yardstick for the assessment ofstandards oftherapy’
  • Survival period is usually reckoned from the date of diagnosis or start of the treatment
  • Quite useful in cancer studies
    studies

    studies

  • Specific death rate:
      • May be cause/ disease-specific or group specific (age-specific, sex-specific, age-sex specific)
      • Help identify particular ‘at risk’ group(s) for preventive action

    Permit comparison between different causes within same population

  • different causes

    different causes

  • Case fatality rate:
      • CFR represents ‘killing power of a disease’
      • It is ‘closely related to virulence of organism’
      • CFR is a Proportion: Always expressed in percentage
      • Limitation of CFR: Time interval is not specified
      • Usefulness of CFR is limited for chronic diseases
    Mortality statistics

    Mortality statistics

  • Is calculated as Observed deaths/ Expected deaths xl 00
  • Permits adjustment for age
  • Standardization may be direct or indirect
  • Indirect standardization: Standardized mortality ratio (SMR):
  • Is simplest and most useful form
  • Feasibility: Permits adjustment where age-specific rates are not available or are unstable because of small numbers
  • Types of population used in standardization:
    • In direct standardization: Mortality rates of population of interest are used (MCQ)
    • Indirect standardization: Mortality rates of standard population are used (MCQ)
  • Direct standardization has greater susceptibility to error with small numbers
  • ASDR : Age specific death rates
  • The rate adjusted to allow for the age distribution of the population is  Age- standardized mortality rate (MCQ)
    • Childhood mortality rates in India
    • Almost 2/3rd of infant mortality rate (IMR) occurs in neonatal period      
    • Almost 2/3r” of the under —five mortality occurs in the first year of life
    • About one in ten children die before they reach the age of five years
    • Infant mortality rate (IMR):
      • Is the ratio of infant deaths registered in a given year to the total number of live births registered in the same year

  • IMR is usually expressed as a rate per 1000 live births (LB).
      • IMR is a rate
      • Is the single best indicator of socio-economic development of a country
      • Is most important indicator o/health status of a community, level of living and effectiveness of MCH services in general.

  • IMR is among ‘the best predictors of state failure’
      • Infant mortality accounts for 18.7 % of total deaths in India
      • MCC of IMR in India: Low birth rate and prematurity (57%)
      • MCC of IMR in World: Pneumonia
      • The latest IMR for the country as per SRS 2011 is 44 per 1000 live births (MP –highest , Kerala –Lowest )

  • Goal in National Population Policy 2000: 10 per 1000 LB by 2010
    • Goal in National Health Policy 2002: 10 per 1000 LB by 2010
    • Neonatal mortality rate (NNMR):
    • Is the number of neonatal deaths (deaths within completed 28 days after birth) per 1000 live births in that year
    • Early neonatal mortality (ENNM): Neonatal mortality in first week (1-7 days) of life
    • Late neonatal mortality (LNNM): Neonatal mortality in first to fourth week (8 – 28 days) of life
    • Early neonatal mortality rate (ENMR),
      • 30/1000 live births.

  • ENMR is an indicator of quality of perinatal care.
    • Neonatal mortality is the ‘most difficult’ part of IMR to alter
      • 98% of neonatal mortality occurs in developing countries
      • NNMR is considered a good indicator of both maternal and newborn health and care

  • The Mortality rate; neonatal (per 1;000 live births) in India was last reported at 32 in 2010, according to a World Bank report published in 2012.
  • MCC of NNMR in India is preterm birth
      • NNMR is directly related with birth weight and gestational age

  • MCC of ENNMR: Prematurity and congenital anomalies
    • MCC of LNNMR: Infections (diarrhea and tetanus)
    • NNMR boys > NNMR girls
    • When no survey or registration data point is available, the NNMR is estimated from the under-5 mortality using a regression adjusted for AIDS

  • Under 5 mortality rate (U5MR):
      • U5MR = No. of deaths of children < 5 years age/ No. of live births in a year X 1000
      • 2015 Millennium Development Goal for under-5 mortality (of less than 38 deaths per one thousand live births),
      • U5MR (India): 56 per 1000 LB [2012]
      • Single MCC of U5MR or CMR is Pneumonia (19%) [diarrhoea – 17%; malaria – 8%].
      • Neonatal conditions lead to 37% of total U5MR or CMR:

  • Infections (MC neonatal condition leading to U5MR)
  • Preterm births
  • Asphyxia
  • UNICEF considers U5MR or CMR as ‘single best indicator of socio-economic development and well being’
  • Child Survival Rate (CSR) (Child Survival Index):
      • Almost 2/3rd of IMR occurs in neonatal period
      • Almost 2/3rd of the U5MR occurs in the first year of life
      • About one in ten children die before they reach the age of five years
    • Post-neonatal mortality rate (PNNMR): Is the number of neonatal deaths (deaths within completed 28 days after birth) per 1000 live births in that year
      • IMR = NNMR + PNNMR = ENNMR + LNNMR + PNNMR

  • Standardized mortality rate is best in order to make a comparison between 2 populations
        • Is a special type of risk ratio: Comparison of observed mortality with expected mortality
        • Is commonly used in occupational studies: Comparison of mortality in an industry and general population
        • Can be used for occurrence of disease (rather than death)

  • Specific death rate:
      • May be cause/ disease-specific or group specific (age-specific, sex-specific, age-sex specific) *
      • Help identify particular ‘at risk’ group(s) for preventive action
      • Permit comparison between different causes within same population
      • At what point in time is the population assessed for calculation of the crude death rate – 1 st July
      • Crude birth rate (CBR): Annual number of live births per 1000 mid-year population

  • Crude death rate (CDR): Annual number of deaths per 1000 mid-year population
    • Crude Birth Rate (CBR): 20.22 per 1000 mid-year population (2013 Statastic)
    • Crude Death Rate (CDR): 7.4 per 1000 mid-year population (2013 Statastic)
    • Growth rate (GR):
      • Is the change in population over time, and can be quantified as the ‘change in the number of individuals in a population per unit time’
      • Annual growth rate (AGR): Crude birth rate (CBR) minus crude death rate (CDR)
      • Decadal growth rate (DGR): Change in population over a decade
      • Growth rate (India):
        • Annual growth rate (AGR): 1.51% (2009 Statastic )
        • Decadal growth rate (DGR): 17.64%
        • Highest DGR (2001-2011):  Meghalaya (27.80%)
        • Lowest DGR (1991-2001): Nagaland (-0.5% ) , Kerala (4.9%)

    Demographic Cycle:

    There are 5 stages (phases) of demographic cycle through which a nation passes

  • Demographic cycle is based on: Demographic gap
    • DG = Crude Birth Rate (CBR) – Crude Death Rate
    • DG starts increasing: Early Stage II (early expanding phase)
    • DG is Maximum: Late Stage II (early expanding phase)
    • DG starts declining: Early Stage III (late expanding phase)
    • DG is Negative: Stage V (Declining phase)
    • DG is Narrow: Stage I (high stationary); Stage IV (low stationary)
  • Important dates in public health:
  • Important days in public health:
  • Indicators of health:
  • Mortality indicators:
  • Crude death rate (CDR)
  • Life expectancy (LE)
  • Infant mortality rate (IMR)
  • Child mortality rate (CMR)
  • Under 5 proportional mortality rate (U5MR)
          • Maternal mortality rate (MMR)

  • Disease specific mortality
  • Proportional mortality rate
  • Morbidity indicators:
        • Incidence and prevalence
        • Notification rates
        • Attendance rates at OPD, health centres
        • Admission, re-admission and discharge rates
        • Duration of stay in hospital
        • Spells of sickness or absence from work/ school

    Disability rates:

  • Nutritional status indicators:
        • Anthropometric measurements of preschool children
        • Heights of children at school entry
        • Prevalence of Low birth weight

  • Health care delivery indicators:
  • Doctor – population ratio
  • Doctor – nurse ratio
  • Population – bed ratio
  • Population per health centre
  • Population per traditional birth attendant
  • Utilization rates:
        • Proportion of infants fully immunized against 6 EPI diseases
        • Proportion of pregnant women who receive antenatal care
        • Percentage of population using various methods of family planning

  • Bed-occupancy rate
        • Average length of stay in a hospital
        • Bed turn over ratio
      • Indicators of social and mental health: Suicide/ homicide/ acts of violence/ road traffic accidents/ alcohol or tobacco use rates
      • Environmental indicators: Air or water pollution indicators, Proportion of population having access to safe water supply and sanitation
      • Socio-economic indicators: Per capita GNP, Level of unemployment, Dependency ratio, Literacy rates
      • Health policy indicators: Proportion of GNP spent on health services, Proportion of GNP spent on health related activities
      • Indicators for quality of life: Physical quality of life index (PQLI)
      • Best indicators of socio-economic development of a country:
        • U5MR (best indicator)
        • IMR (2nd best indicator)
      • Denominator in CDR and CBR: Mid-year population Life expectancy (LE):
      • Life Expetancy  is a POSITIVE mortality indicator
        • LE is used for derivation of:

  • PQLI
  • Human development index (HDI)
  • Maternal mortality rate (MMR):
        • MMR is a ratio

  • Is calculated and expressed ‘per 1 lac live births’
        • RHIME (Representative, re-sampled, routine household interview of mortality, with medical evaluation):
          • Is a new     method for MMR estimation introduced in India from 2003
        • MCC of MMR in World: Obstetric hemorrhage (25%).

  • MCC of MMR in India: Obstetric hemorrhage (38%).
      • Maternal mortality is ‘a sentinel event to assess the quality of a health care system’

    • In an outbreak of cholera in a village of 2000 population 20 cases have occurred and 5 have died. Case fatality rate is –       25% (MCQ)
      • Case fatality rate (CFR) = Total no. of deaths due to a disease/ Total no. of deaths due to a disease X 100
      • CFR=5/20*100=25%
            • And, Survival rate = 1 – CFR = 1 – 0.25 = 0.75 (75%)

      • Standardization (MCQ)
      • Standardization allows comparison to be made between two different populations
            • Standard population: Is a population where numbers in each age and sex group are known

      • For direct Standardization, age specific rates of the study population are applied to that of the standard population
      • For Indirect Standardization age specific rates of the standard population are applied to the study population
            • Standard population: Is a population where numbers in each age and sex group are known
          • Examples of indirect Standardization:
            • Standardized Mortality Ratio (SMR)

      • Life Table Analysis
      • Survival Analysis
      • Regression Analysis
      • Multivariatc Analysis
        • Direct standardization is used to compare the mortality rates between two countries. This is done because of the differences in – Age distributions (MCQ)
        • SMR is commonly used in occupational studies = (observed deaths /Expeced deaths) x 100
        • Case fatality rate
          • best indicator of the severity of an acute disease
          • CFR represents ‘killing power of a disease’.

      • It is ‘closely related to virulence of organism’
      • CFR is a Proportion: Always expressed in percentage
          • Time interval is not specified in CFR;
          • CFR may vary in different epidemics
          • Usefulness of CFR is limited for chronic diseases
          • CFR is the ‘complement of Survival Rate’
          • CFR = 1 – Survival Rate
          • Maximum power of destruction of a disease is measured by : Case fatality rate

      • Estimating the burden of particular disease in a community is measured  : Proportional mortality rate
        • Sullivian Index: Measures like expectancy adjusted without disability or free of disability
        • Specific death rates:
          • Specific for age and sex

    • Identify particular group or group “at risk for preventive action”
        • Find out cause or disease specific
      • Proportional mortality rate estimates the burden of a disease in the community is
      • Severity of the disease best assessed by: Case fatality rate

    • International Death Certificate
        • In WHO recommended Death Certificate, Underlying Cause of Death is recorded on – Line Ic (MCQ)
        • WHO RECOMMENDED DEATH CERTIFICATE (for International use):
          • Consist of four lines:
            • Line la: Disease or condition directly leading to death
            • Line Ib: Antecedent/ underlying cause
            • Line Ic: Main antecedent/ underlying cause
            • Line II: Other significant conditions contributing to death BUT not related to disease/ condition causing it

    • Example of a death certificate:
            • Line la: Renal failure
            • Line Ib: Diabetic nephropathy
            • Line Ic: Diabetes mellitus
            • Line II: Hypertension
        • Concept of underlying cause, Line Ic is the MOST IMPORTANT line in death certificate, thus also known as ‘Essence of Death Certificate’
        • Goal for registration of vital events in India: 100%  of 4 vital events by 2010 (under National Population Policy 2000)

    • Birth
    • Death
    • Marriage
    • Pregnancy
      • Legislations governing registration of vital events in India:
        • Birth: Central Births and Deaths Registration Act’ 1969
        • Death: Central Births and Deaths Registration Act’ 1969
        • Marriage: The Hindu Marriage Act, 1955
        • Pregnancy: No legislation yet in India

      Current norms for registration of vital events in India: