Question

If the incidence rate of a very serious disease is 25/100,000 person-years and the prevalence of this disease in the population is 75/100,000, what is the average survival time of individuals who contract this disease? [Assume the population is in steady state.

Answer 1

Answer:

Explanation:

Mathematiclly;

Prevalence of a diseases = product of disease incidence  and the average survival time.

Prevelence =   (incidence) X (average survival time.)

( 75/100,000 )=  (25/100,000) X       ????.

but 75/100,000 =0.00075. (Prevalence)

and 25/100,000= 0,0025.  ( Incidence)

Therefore ;

AVERAGE SURVIVAL TIME = (PREVALENCE / INCIDENCE    

                                                      = 0,00075/0,00025.

    AVERAGE SURVIVAL TIME        = 3 years.

Thus it took them a period of 3 years to survive from diagnosis till death.