A retrospective study was conducted using data collected at a hospital in Spain during the COVID-19 pandemic. The goal was to analyze the incidence of acute kidney injury (AKI) in patients with SARS-CoV-2 infection. Patients were considered to have COVID-19 if they had a positive test result or if they had symptoms and other factors that suggested infection. To be included in the study, patients had to have been hospitalized due to related problems like hypoxemic respiratory failure, sepsis, or viral pneumonia. Patients with AKI were identified as those who had an increase in creatinine levels during their hospitalization. The cause of the AKI was determined by a team of experts based on the patients' medical records and other health information. The control group consisted of patients who were admitted to the hospital during the study period and did not have AKI. The control group was selected to be the same size as the AKI group.The study concluded that COVID-19 was associated with a high incidence of AKI, and that early recognition and proper management of the condition is important for patient outcomes. 1) Based on the study description, which control sampling approach did the researchers use? a) Incidence density sampling b) Row 2 sampling c) Row 3 sampling 2) For this item, assume that the disease was considered rare. Based on your answer to the previous question, which measure(s) does the exposure odds ratio (EOR) from the study approximate? a) Rate ratio b) Risk odds ratio c) Risk ratio.

1. A retrospective study was conducted using data collected at a hospital in Spain during the
COVID-19 pandemic. The goal was to analyze the incidence of acute kidney injury (AKI) in
patients with SARS-CoV-2 infection. Patients were considered to have COVID-19 if they had a
positive test result or if they had symptoms and other factors that suggested infection. To be
included in the study, patients had to have been hospitalized due to related problems like
hypoxemic respiratory failure, sepsis, or viral pneumonia.
Patients with AKI were identified as those who had an increase in creatinine levels during their
hospitalization. The cause of the AKI was determined by a team of experts based on the patients'
medical records and other health information. The control group consisted of patients who were
admitted to the hospital during the study period and did not have AKI. The control group was
selected to be the same size as the AKI group.The study concluded that COVID-19 was
associated with a high incidence of AKI, and that early recognition and proper management of
the condition is important for patient outcomes.
1) Based on the study description, which control sampling approach did the researchers use?
a) Incidence density sampling
b) Row 2 sampling
c) Row 3 sampling
2) For this item, assume that the disease was considered rare. Based on your answer to the
previous question, which measure(s) does the exposure odds ratio (EOR) from the study
approximate?
a) Rate ratio
b) Risk odds ratio
c) Risk ratio