Exam 18: Epidemiologic Approach to Evaluating Screening Programs

Epidemiologists decided to investigate the validity of new diagnostic tool for breast cancer.They used this new diagnostic tool for breast cancer in 150 women with biopsy-proven breast cancer in 300 age- and race-matched control women.The results of the new tool were positive in 136 cases and in 35 control women,all of whom showed no evidence of cancer at biopsy.Now,the epidemiologists want to use the new diagnostic tool for screening program in Cities A and B.Based on previous cross-sectional studies,the prevalence of breast cancer is 5% in City A and 1% in City B.What is the expected positive predictive value of new diagnosis tool for breast cancer in City A?

Which of the following statements is the most accurate example of tertiary prevention?

Which of the following statements is the most accurate example of secondary prevention?

Which of the following statements is not an accurate description of epidemiologic studies using large group data such as National Hospital Discharge Survey or National Health Interview Survey?

In the model of the Natural History of Disease,the period of time between the onset of signs and symptoms of disease and its ultimate outcome (cure,control,or death) is known as

Which of the following statements is the most accurate example of primary prevention?

The usual time to death after diagnosis of disease X is 2 years.A screening program allows for the early detection of disease X,on average 1 year earlier than the usual diagnosis; however,there is no available treatment even in early stages of disease X.With the screening program it seems like the time to death has increased to 3 years; however,this is only due to the early diagnosis thanks to the screening program.What is the name of the issue previously described?

The following is a reason for an apparent lack of benefit from a screening program:

In the model of the Natural History of Disease,when is the ideal time to do screening for a disease?

Epidemiologists decided to investigate the validity of new diagnostic tool for breast cancer.They used this new diagnostic tool for breast cancer in 150 women with biopsy-proven breast cancer in 300 age- and race-matched control women.The results of the new tool were positive in 136 cases and in 35 control women,all of whom showed no evidence of cancer at biopsy.What is the sensitivity of new diagnosis tool for breast cancer?

Epidemiologists decided to investigate the validity of new diagnostic tool for breast cancer.They used this new diagnostic tool for breast cancer in 150 women with biopsy-proven breast cancer in 300 age- and race-matched control women.The results of the new tool were positive in 136 cases and in 35 control women,all of whom showed no evidence of cancer at biopsy.Now,the epidemiologists want to use the new diagnostic tool for screening program in Cities A and B.Based on previous cross-sectional studies,the prevalence of breast cancer is 5% in City A and 1% in City B.What is the most reasonable conclusion to be drawn from these data?

A recent study found that screening for disease X led to increased survival.In the study,those who were screened were generally younger,healthier,and more aware of their health than those who were not screened.This makes it hard to evaluate whether the improvement in survivorship was due to the screening program or due to the characteristics of those who are screened.What is the name of this issue when evaluating the effect of a screening program?