False about case fatality rate: March 2011
Ans. B: Denominator is mid-year population Case fatality rate= Total number of deaths due to a disease X 100/ Total number of cases due to that disease Case fatality/Fatality rate: It is the ratio of deaths within a designated population of people with a paicular condition, over a ceain period of time. An example of a fatality rate would be 9 deaths per 10,000 people at risk per year. This means that within a given year, out of 10,000 people formally diagnosed with a disease, 9 died. Rabies, if contracted by an unvaccinated individual who does not seek prophylactic treatment, is also an extremely deadly virus, with a case fatality rate approaching 100%. Moality rate: It is a measure of the number of deaths (in general, or due to a specific cause) in a population, scaled to the size of that population, per unit time. Moality rate is typically expressed in units of deaths per 1000 individuals per year; thus, a moality rate of 9.5 in a population of 100,000 would mean 950 deaths per year in that entire population, or 0.95% out of the total. It is distinct from morbidity rate, which refers to the number of individuals in poor health during a given time period (the prevalence rate) or the number of newly appearing cases of the disease per unit of time (incidence rate). The term "moality" is also sometimes inappropriately used to refer to the number of deaths among a set of diagnosed hospital cases for a disease or injury, rather than for the general population of a country or ethnic group. This disease moality statistic is more precisely referred to as "case fatality". One Distinguishes: The crude death rate, the total number of deaths per year per 1000 people. The perinatal moality rate, the sum of neonatal deaths and fetal deaths (stillbihs) per 1000 bihs. The maternal moality ratio, the number of maternal deaths per 100,000 live bihs in same time period. The maternal moality rate, the number of maternal deaths per 1,000 women of reproductive age in the population (generally defined as 15-44 years of age). The infant moality rate, the number of deaths of children less than 1 year old per 1000 live bihs. The child moality rate, the number of deaths of children less than 5 years old per 1000 live bihs. The standardized moality rate (SMR)- This represents a propoional comparison to the numbers of deaths that would have been expected if the population had been of a standard composition in terms of age, gender, etc. The age specific moality rate (ASMR) - This refers to the total number of deaths per year per 1000 people of a given age.
Represents the killing power of disease
Denominator is mid-year population
Indicates virulence power of causative agent
Not much useful for chronic diseases