NR 503 Epidemiology Final Exam (Latest): Chamberlain College of Nursing

NR 503 Epidemiology Final Exam (Latest): Chamberlain College of Nursing (FOR 100% CORRECT ANSWER CHECK THE LAST PAGE) Question A randomized, double-blind clinical trial of a varicella vaccine observed an estimated incidence of 25% chickenpox episodes in persons receiving the vaccine, compared to 80% among persons receiving a placebo. The estimated efficacy of the vaccine is: Explanation The efficacy is calculated by subtracting the rate in those vaccinated from the placebo rate and dividing by the placebo rate. In this example, 80% minus 25% equals 55%. Dividing by 80% results in an efficacy of 68.8%. Question A study is conducted for a pharmaceutical agent that has shown promise for reducing heart disease among women. In order to more fully test the agent, an additional study is done restricting the participants to be randomized to those who have a history of hypertension. Which of the following advantages cannot be claimed by the researchers? Explanation Restricting the study to a high-risk group will only fail to increase the generalizability of the findings since the study results will apply only to a more specific group of women who share a history of hypertension. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the incidence of needing a blood transfusion in the group of persons who were randomized to the new drug treatment? Explanation Incidence is the development of the outcome under investigation among those at risk. In this instance, 43 participants “developed” the need for a blood transfusion among the 84 persons in the new drug treatment group. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the number of persons who died in hospital in the study? Explanation The death rate in the study for all participants is 0.167. Multiplying this number by 168, the total number of participants, results in 28 deaths in hospital following treatment. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the main advantage of the randomization of the 168 study participants to one of the two drug treatment groups? NR 503 Epidemiology Final Exam (Latest): Chamberlain College of Nursing (FOR 100% CORRECT ANSWER CHECK THE LAST PAGE) Question A randomized, double-blind clinical trial of a varicella vaccine observed an estimated incidence of 25% chickenpox episodes in persons receiving the vaccine, compared to 80% among persons receiving a placebo. The estimated efficacy of the vaccine is: Explanation The efficacy is calculated by subtracting the rate in those vaccinated from the placebo rate and dividing by the placebo rate. In this example, 80% minus 25% equals 55%. Dividing by 80% results in an efficacy of 68.8%. Question A study is conducted for a pharmaceutical agent that has shown promise for reducing heart disease among women. In order to more fully test the agent, an additional study is done restricting the participants to be randomized to those who have a history of hypertension. Which of the following advantages cannot be claimed by the researchers? Explanation Restricting the study to a high-risk group will only fail to increase the generalizability of the findings since the study results will apply only to a more specific group of women who share a history of hypertension. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the incidence of needing a blood transfusion in the group of persons who were randomized to the new drug treatment? Explanation Incidence is the development of the outcome under investigation among those at risk. In this instance, 43 participants “developed” the need for a blood transfusion among the 84 persons in the new drug treatment group. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the number of persons who died in hospital in the study? Explanation The death rate in the study for all participants is 0.167. Multiplying this number by 168, the total number of participants, results in 28 deaths in hospital following treatment. Question A new drug treatment for cardiac thrombus claims to have a higher success rate than the current drug. A strong sign of the potential success is the lack of internal hemorrhaging starting 2 days after treatment. 168 patients who require treatment for cardiac thrombi are randomized after agreeing to participate in a trial of the new drug. The researchers were interested in whether the new drug reduced the need for blood transfusions due to internal hemorrhage compared to the current treatment. The following table summarizes the results of her study: What is the main advantage of the randomization of the 168 study participants to one of the two drug treatment groups?