Morbidity and Mortality - Definition, Types, and Indicators

MORBIDITY AND MORTALITY  To review about health indicators  To understand meaning of mortality  To explain the limitations of mortality indicators  To list out the uses of mortality indicators  To define the mortality indicators  To explain the meaning of morbidity  To enumerate t...

MORBIDITY AND MORTALITY  To review about health indicators  To understand meaning of mortality  To explain the limitations of mortality indicators  To list out the uses of mortality indicators  To define the mortality indicators  To explain the meaning of morbidity  To enumerate the types of morbidity rates  To explain the meaning of prevalence and incidence rate  To compare the relationship between prevalence and incidence  To define compression of morbidity rate INDICATORS OF HEALTH :- The indicators of health may be classified as follows: Mortality indicators Morbidity indicators Disability rates Nutritional status indicators Health care delivery indicators Utilization rates Indicators of social and mental health Environmental indicators Socioeconomic indicators Health policy indicators Indicators of quality of life Other indicators MORTALITY :- Mortality is the condition of being mortal, or susceptible to death; the opposite of immortality Limitation in mortality data Incomplete reporting of death Lack of accuracy Lack of uniformity Choosing a single cause of death Changing coding system and changing fashion in diagnosis Diseases with low vitality  USES OF MORTALITY DATA  In explaining trends and differentials in overall mortality  Indicating priorities for health action and allocation of resources  In designing intervention programme and  Assessment and monitoring of public health problems and programmes  Gives clues for epidemiological research  MORTALITY INDICATORS and MORTALITY RATES AND RATIOS It is defined as the number of death per 1000 estimated midyear population per year in a given community. It indicates the rate at which people are dying.  Crude Death rate = no: of death occurred in an year х 1000 Estimated mid - year population The crude death rate summarizes the effect of two factors; Population composition Age – specific death rates Death rate of India : 6.23 deaths/1,000 population (July 2009 est.) Life expectancy at birth is “the average number of years that will be lived by those born alive into a population if the current age specific mortality rates persist”  It is estimated for both sex separately.  Life expectancy is a good indicator of socioeconomic development in general.  As an indicator of long term survival , it can be considered as a positive indicator.  Help to identify what is happening to overall standard of living of people in India.  One of the broadest standard of living measure is the life expectancy - the average expected lifespan of an Indian is ;  Total population: 69.89years male : 67.46years female : 72.61 years (2009 est.)  Infant mortality rate is defined as “ the ratio of infant deaths registered in a given year to the total number of live birth registered in the same year; usually expressed as a rate per 1000 live births” IMR= no: of death under 1yr age in 1х1000 No: of live birth during that year Infantmortalityrate:  total: 30.15deaths/1,000livebt male: 34.61deaths/1,000livebirt hs female: 25.17 deaths/1,000 live births (2009 est.)  NEONATAL MORTALITY RATE  Neonatal mortality rate:  = no of death ,under 28 days of age occurred during a yх1000. no of live birth during that year i  MATERNAL MORTALITY RATE; Maternal death is defined as the death of a woman while pregnant or within 42 days of termination of pregnancy irrespective of the duration ,and the site of pregnancy from any cause related to or aggravated to by the pregnancy or its management but not from accidental or incidental causes.  MMR = no of female death from pregnancy,child birth,or Puerperial causes in an year \ х1000 no of live birth in same area during that year Journal study Changing trends in maternal mortality over a decade  study the change in trend in maternal mortality over the last decade and to find out specific causes of death. Method: A retrospective study was carried out. The admission ledgers of patients admitted over two 3-year periods (1979–1981 and 1989– 1991) were studied to ascertain the total number of maternal deaths and the specific causes of death FETAL DEATH RATES  The WHO subdivided the fetal death based on gestation as follows :  Early : under 20 weeks  Intermediate : 20 to 27 weeks  Late : 28 weeks and over The still birth rate (late fetal death rate) correspond to Still birth rate = no of fetal death, 28wks of gestation or more occurred during a yх1000 no of live birth plus late fetal death during that year  Late foetal death rate = no of foetal death,28 week of gestation Or more occurred during a yr х1000 \ No of live births during that year It is defined as the number as the number of death at age 1- 4 yrs in a given year ,per 1000 children in that age group at the midpoint of the year concerned. It thus excludes infant mortality. CHILD SURVIVAL INDEX:- A child survival rate per 1000 birth can be simply calculated by subtracting the under 5 mortality rate from 1000 dividing this figure by ten shows the percentage of those who survive to the age of 5yrs Child survival rate = 1000 – under 5 mortality rate 10 Disease specific mortality Mortality rates can be computed for specific diseases. As countries begin to extricate themselves from burden of communicable disease, a number of other indicators emerged as measures of specific disease problem. PROPOTIONAL MORTALITY RATE  It is useful to know what proportion of total death are due to particular disease.(eg cancer) The simplest measure of estimating the burden of a disease in the community is proportional mortality rate.. ie, the proportion of all death currently attributed to it.Proportional mortality rate for a specific disease; is = No of deaths from the specific disease inyear x 100/ Total death from all causes in that year CASE FATALITY RATE:- = total no of death due to a particular diseasx100 total no of cases with same disease  It determines the killing power of a disease  It is simply the ratio of death to case  It is typically used in acute infectious diseases( eg: food poisoning, cholera etc) Specific mortality rate:-  This rate can be made specific with regard to any subgroup of the population such as  age specific death rate for group A  sex specific death rate for sex M or  cause specific death rate for cause C.  A refers to a specific age; C refers to specific cause of death; M and F refers to their gender. Age specific death rate for A  = no of death of age A in an year х1000 Estimated population of age A midyear sex specific death rate for group M =no of death of sex M in an year х1000 estimated population of sex M midyear  Cause specific rate= no of death due to cause C occurred in a yearх1000 estimated midyear population Adjusted or standardized rates:  If we want to compare the death rates of two populations with different age- composition, we can use ‘age adjustment “or “age Standardization’”.  There are two ways of computing standardized death rates – direct and indirect standardization.  Direct Standardization (SDR1) calculates a weighted average of the region’s age-specific mortality rates  Indirect Standardization (SDR2) uses age-specific mortality rates from the standard population to derive expected deaths in the region’s population Direct Standardization:  SDR1 = [∑ age groups (Mar Pas)]/Ps x 1000  Mar is the age-specific mortality rate for the region. Pas is the number of people in the age group in the standard population. Ps is the total standard population. INDIRECT STANDARDISATION  SDR2 = Dr/[∑ age groups (Mas Par)] x CDRs  Mas is the age-specific mortality rate for the standard population. Par is the number of people in the age group in the region’s population. Dr is the number of deaths in the region. CDRs is the crude death rate for the standard population. MORBIDITY Morbidity has been defined as “any departure, subjective or objective, from a state of physiological well being”. The problem is equivalent to such terms as sickness , illness, disability etc.  The WHO Expert committee on Health Statistics noted in its 6th report that morbidity could be measured in terms of 3 units-  a. person who ill ;  b. the illness that these persons experienced and  c. the duration of these illness.  The value of morbidity data is summarized as;  They describe the nature and extend of the disease load in the community and thus assist in the establishment of priorities  They usually provide more comprehensive and more accurate and clinically relevant information on patient characteristic.  They act as starting points for aetiological studies, and thus play a crucial role in disease prevention  They are needed for monitoring and evaluation of disease control activities  Morbidity indicators:-  To describe health in terms of mortality is misleading. This is because the mortality indicators do not reveal the burden of ill health in a community , as for example mental illness and rheumatoid arthritis. Therefore morbidity indicators are used to supplement mortality data to describe the health status of a population. Morbidity statistics have also their own drawback; they tend to overlook a large number of condition which are subclinical or inapparent , that is , the hidden part of the iceburg of disease The following morbidity rates are used for assessing the ill health in the community.  Incidence and prevalence  Notification rates  Attendance rate at outpatient department, health centres ,etc  Admission readmission and discharge rates  Duration in hospital and Spells of sickness or absence from work or school Incidence  Incidence rate is defined as : “the number of NEW cases occurring in a defined population during a specified period of time”. It is given by the formula.  Incidence = no of new case of specific disease during given time period/ х1000 Population at risk during that period incidence rate refers  Only to new cases  During a given period(usually one year)  In a specified population or “population at risk” ,unless other denominators are chosen  It can also refer new spells or episodes of disease arising in a given period of time , per 1000 population. For example , a person may suffer from common cold more than once a year. If he had suffered twice , he would contribute two spell of sickness in the year. The formula in this case would be  Incidence rate(spell) = no of spells of illness starting in a defined period х1000 mean no of person exposed to risk in that period PREVALENCE  The term disease prevalence refers specifically to all current cases( old and new) existing at a given point of time , or over a period of time in a given population  DEFINITION  “thetotal number of all individuals who have an attribute or disease at a particular time ( or during a particular period) divided by the population at risk of having the attribute or disease at this point in time or midway through the period”. Prevalence is of two type; Point prevalence Period prevalence Point prevalence:-  Point prevalence of a disease is defined as the number of all current cases ( old and new) existing at a given point of time in relation to a defined population.  The “point” in point prevalence, may for all practical purpose consist of a day ,several days or even few weeks depending upon the time it takes to examine the population sample. It is given by the formula;  = No of all current cases (old & new)of a specified disease at a given point in time / х100 Estimated population at the same point in time  Period prevalence:- A less commonly used measure of prevalence is period prevalence. It measures the frequency of all current cases (old and new) existing during a defined period of time ( eg:- annual prevalence) expressed in relation to a defined population.  It includes cases arising before but extending into or through to the year as well as those cases arising during the year. period prevalence is given by the formula : = no of existing cases(new& old) of a specific disease during a given period of time interval / х100 estimated mid interval population at risk Relationship between prevalence and incidence:-  Prevalence depends upon 2 factors , the incidence and duration of illness. given the assumption that the population is stable , and incidence and duration are unchanging , the relationship between incidence and prevalence can be expressed as:  P= I х D=incidence х mean duration Uses of prevalence:_-  Helps to estimate the magnitude of health/ disease problems in the community and identify potential high risk population  Prevalence rates are especially useful for administrative and planning purpose , eg: hospital beds , manpower needs , rehabilitation facilities ,etc. THANK YOU