A drug, which does not cure a disease but decreases its symptoms and increases survival, leads to?

Ans. a. Increased prevalence (Ref: Park 23/e p61, 22/e p59)A drug, which does not cure a disease but decreases its symptoms and increases survival, means its leads to increased duration of disease and increased prevalence.Prevalence = No. of total (old + new) cases of a disease in a year/Total population x 100 Prevalence = Incidence x Mean duration of diseasePrevalence is the proportion of a population that has a condition at a specific time, but the prevalence will be influenced by both the rate at which new cases are occurring and the average duration of the disease. Incidence reflects the rate at which new cases of disease are being added to the population (and becoming prevalent cases). Average duration of disease is also important, because the only way you can stop being a prevalent case is to be cured or to move out of the population or die. "PrevalencePrevalence is the total current (Old+ new) cases in a given population over a point or period of timeQ.Types: Point prevalence (at a point of time) & Period prevalence (over a period of time)QPrevalence = No. of total (old + new) cases of a disease in a year/Total population x 100QPrevalence is a proportion, not a ratio: Numerator is a part of denominator, and is always expressed in percentage.Prevalence can be determined from cross-sectional studyQ.Relation between Incidence & PrevalenceGiven the assumption that population is stable & incidence and duration are not changing.Prevalence = Incidence x Mean duration of diseaseQPrevalence describes balance between incidence, mortality and recoveryQ.Incidence reflects causal factorsQ.Duration reflects prognostic factorsQ