Exam 5: Epidemiology, Biostatistics, and Medical Informatics

A research is being done to evaluate the efficacy of beta-blocker medication in patients suffering from acute myocardial infarction (MI). The study discovered that 20 individuals out of 90 who used a beta-blocker in the week preceding a MI experienced a severe arrhythmia incident while hospitalized. The study also discovered that 30 of the 70 individuals who did not use a beta-blocker suffered a severe arrhythmia. What was the chances ratio of getting significant arrhythmia in individuals who used beta-blockers against those who did not?

A clinical trial is looking at the use of five distinct biomarkers for detecting Barrett esophagus (BE), the only known precursor lesion of esophageal cancer. Researchers assess each biomarker's performance and offer estimates of sensitivity, specificity, and area under the curve (AUC).   Which biomarker is the most reliable?

Angiotensin-converting enzyme (ACE) drugs were studied in the prevention of cardiac events in diabetic individuals. During a 5-year follow-up period, 120 of 400 diabetic individuals who had taken an ACE inhibitor suffered an acute coronary event. During the same time period, 100 of 300 diabetic individuals who did not use an ACE inhibitor suffered a cardiac incident. What was the risk of suffering a cardiac incident in diabetes individuals on ACE inhibitors versus diabetic patients not taking ACE inhibitors?

A research is being done to evaluate the prevalence of catheter-associated urinary tract infection (CAUTI) in an urban hospital's critical care unit (ICU). The graph below depicts the number of CAUTI cases among ICU patients in this hospital for the month of July. Which of the following is the number of common cases on July 31 based on the plot?

A novel biomarker for the early identification of invasive stomach cancer has been found. When compared to endoscopy with several biopsies, it offers a sensitivity of 89 percent and a specificity of 85 percent. The test is employed in two populations: one in the United States, where 5 out of 100,000 people have stomach cancer, and another in China, where 100 out of 100,000 people have the disease. Which of the following statements about this new test is the most accurate?

In 2016, the population of a state was expected to be 4,000,000 people. The state recorded 20,000 cases of a rare and deadly neurological illness at the start of the same year. The state recorded 7,000 new cases and 1,000 fatalities linked to this illness by the end of 2016. At the conclusion of the year, another 40,000 fatalities from all causes were documented. What was the disease's cumulative incidence in 2016?

A novel test for detecting the presence of a recently discovered biomarker for hepatocellular cancer has been developed by researchers (HCC). The preliminary results of the test reveal the following:  Which of the following is the most likely explanation for a negative test result?

A 73-year-old man visits the office for a check-up. He was diagnosed with CLL three years ago after normal laboratory tests indicated a significantly high leukocyte count. He is in good spirits. On examination, he was found to have stable lymphadenopathy. He has been researching treatment alternatives if his CLL progresses and is interested in an investigational medication that preferentially binds malignant cells. The medicine has been proven to considerably improve survival in people with stage 3 and 4 CLL while not curing the disease. If this new drug were widely used, what changes would be expected in the number of incident and prevalent cases of CLL?

A rheumatoid arthritis (R A) genome-wide association study (GWAS) is being conducted on a cohort of Portuguese patients, including 907 cases with RA and 1,524 controls without RA. To examine the relationship between RA and hundreds of thousands of loci, logistic regression is performed. These findings are then compared to data from a European GWAS cohort of 4,036 RA patients and 6,959 non-RA patients. Finally, the findings of the Portuguese and European studies are merged in a meta-analysis. Based on these findings, the researchers discover three additional loci related with RA using a significance level criterion of 5 - 10⁸:   Previous research has found 30 loci that accounted for 35% of RA disease heredity. Which of the following statements is correct regarding this study?

A pediatrician evaluates a group of 1,000 youngsters using a new asthma test. Asthma is common in this group, with a 10% frequency. The pediatrician's diagnostic test has a sensitivity of 95% and a specificity of 80%. Which of the following statements best describes the possibility that a kid in this demographic with a positive test result has asthma?

Researchers are working on an enzyme-linked immunosorbent assay test for rheumatoid arthritis diagnosis. The test is intended to identify serum antibodies against citrullinated proteins. Two test populations with varying rheumatoid arthritis prevalence are chosen. The researchers want to compare a variety of diagnostic test parameters to assess the test's performance in the two groups. Which of the following performance indicators is most likely to differ between the two test populations?

The graph below depicts the yearly incidence of viral hepatitis per 100,000 people in the United States from 1982 to 2012. (US). The overall population of the United States increased throughout this time period, as seen in the table below: 11ec160b 371f 9291 9249 659e3ae21c65 MD0001 00 The number of people at risk of hepatitis infection is considered to be equal to the whole US population at any given moment. Which of the following is more likely based on this information?

A sample of children age 2-5 years is chosen at random from an outpatient clinic.  The number of urinary tract infections (UTIs) over a 1-year period is given in the figure below. What was the average number of UTI episodes over 1 year for a child in this sample?

Treatments A and B are two new investigational drugs being evaluated for the treatment of an unique respiratory virus infection in children that causes abrupt respiratory collapse and mortality. The 2-week survival following treatment is analyzed as part of the testing procedure to establish the clinical effectiveness of the investigational medications. A total of 60 children who have just been diagnosed with the condition are randomly randomized to take Drug A, Drug B, or placebo in a 1:1:1 ratio.   which of the following statements comparing the effectiveness of Drugs A and B in treating children infected with the novel virus is most appropriate?

A study was undertaken by a research group to examine creatine kinase-MB (CK-MB) levels in type 2 diabetic mellitus (T2DM) patients receiving statin medication. Participants were placed into four treatment groups. T2DM patients in Groups I, II, and III had received statin treatment (atorvastatin, simvastatin, and rosuvastatin, respectively) for at least 6 months. Group IV included T2DM individuals who had not received statin medication. Which of the following statistical tests is most appropriate for comparing CK-MB levels in this study's Groups I, II, III, and IV?

A total of 1,040 women with SLE and 1,260 women without SLE are recruited for a case-control research to look at a possible link between endometriosis and SLE. In both groups of women, the investigators question about a history of endometriosis. 240 women with SLE had a history of endometriosis, while 210 women without SLE had a history of endometriosis. What is the estimated chances ratio of endometriosis in women with SLE vs women without SLE?

A hospital wants to know how common diabetic nephropathy is in the general population of persons with type 2 diabetes. Kidney biopsy samples are collected from 500 adult diabetic patients receiving medical treatment. The samples are then analyzed by ten different pathologists, five of whom work at the hospital and five at surrounding institutes. According to early findings, pathologists who work for the hospital are three times more likely than those who do not work for the hospital to interpret biopsy samples as diabetic nephropathy. Which of the following is the most plausible explanation for this discrepancy in interpretation?

A randomized, double-blind, placebo-controlled clinical study of a novel medication for the treatment of peripheral neuropathy in adults with multiple myeloma is being conducted by an investigator (MM). The trial includes 150 individuals with MM who are randomly assigned to receive either the new medicine (n = 75) or a placebo (n = 75). According to the trial design, participants in both groups must take one medication every day and keep a pain diary. After three months of therapy, each patient is interviewed and their pain diaries are examined; nine patients on the new medicine and three patients on the placebo did not take the tablets as directed. The investigator decides to analyze the trial data using the intention-to-treat principle.  Which of the following best describes how the data pertaining to all patients who did not adhere to protocol should be treated?

A group of researchers conducted a case-control study to determine the link between pesticide exposure and head and neck squamous cell carcinomas. Cases and controls were age and gender matched. The individuals' exposure status was assessed through interviews. The odds ratio in matched-pair analysis is 7.5. (95 percent confidence interval: 2.3-14.8). Based on this information, which of the following is most likely to have an impact on the study's validity?

A doctor is undertaking a double-blind randomized controlled experiment to see if a new cream might lower the likelihood of recurrence in chronic recurrent atopic dermatitis. A total of 30 patients with moderate to severe atopic dermatitis who were undergoing a flare were randomly divided into two groups: 15 received the new cream, and 15 received just emollient. After two weeks of therapy, the new cream group had a 25% recurrence rate, whereas the emollient alone group had a 50% relapse rate. The difference, however, is not statistically significant (p = 0.14). According to the doctor, using the new cream does not lessen the likelihood of recurrence in chronic recurrent atopic dermatitis. Which of the following is most likely to explain the results of the study?