Incidence & prevalence - sunroyal

[ArchivalUser]

can anyone explain me the difference on denominator basis for incidence & prevalance i m getting confused.

[ArchivalUser]

incidence=new cases in a given period of time/population at risk during the same period...
that is to get the denominator we have to substract the diseased from the total population as they are not at risk for developing the disease
for example...if there are 100 new cases of a disease in a one year and the toatl population is 100000 then incidence=100/(100000-100)



Prevalence=total no of cases in the given population/entire population
example...if there are 500 cases of a disease in a given population of 100000 then
prevalence=500/100000


hope this helps

[ArchivalUser]

Thx stranger

[ArchivalUser]

actually ehy i got confusion is at denominator in first aid they gave population at risk for both incidence & prevalence.my question is why diseased person is himself risk in prevalence.i need explanation for that

[ArchivalUser]

incidence is new cases so once a patient is diseased he cannot become new case again hence we substract the news case with the total population

but in prevalence u are calculating the total people who are diseased irrespective of new or old hence u take total population in the denominator

[ArchivalUser]

thq

[ArchivalUser]

ur welcome :-)

[ArchivalUser]

in other words

incidence = number of new cases / number of people at risk of becoming a new case
if somebody has disease, he definitely is not at risk of becoming a new case

prevalence = number of cases / number of people at risk of being a case
denominator here is total pop like stranger said

[ArchivalUser]

Perfectly explained!