Question

The CUCG MPH Epidemiology students’ research team is planning to conduct a case-control study of the association between lack of adequate PPEs and covid19 infection among staff of Komfo Anokye Teaching Hospital in Kumasi. The students plan to study exposed nurses from the wards of the hospital as cases and unexposed nurses on retirement who live within the hospital flats as controls. As a reviewer of the research proposal;

a. Explain the type of bias which could arise from this study?

b. During the subject recruitment, most nurses on the ward for fear of covid19 stigmatization declined to enroll so the researchers recruited nursing administrators and other administrative staff who also work in the wards of the hospital. Explain the type of bias this particular decision could lead to.

c. Following your review, the students decided to change their research title to “Lack of adequate PPEs and covid19 infection within the Kumasi metropolis” and decided to use the nurses in Komfo Anokye Teaching Hospital as controls whilst recruiting the general Kumasi community for their subjects, discuss the type of bias they would be faced with.

Answer 1

a)

Answer: Bias is defined as false or mistake result obtained from a research study due to error in design or conduct of the study. The types of bias that could be arise from this study are

- Selection bias : This bias occurs during the identification of the study population. In this study the controlled group is the retired nurse. The control group should be people who are working in hospital with adequate PPE. That time only the association between the lack of PPE and ocurance of COVID 19 can be identify.

- Non- responsive bias- The individual may not response to participate in the study.

- Withdrawal bias: This bias is occurs due to drop down of the participants during the study.

b)

It is non responsive bias. Non responsive bias is comes under the selection bias. The people are not responding or rejected to enrolled due to their fear of getting the COVID 19.

c)

Answer: As the sample are the people of community and controlled group is the staff nurse which is not reliable because the objective of the study is to check the association of lack of PPE and occurrences of COVID 19 among health workers who are working in the hospital. The sample does not represent the desired population. It is participation bias which means that the participants are often different from the people who do not want to join. Participation bias is one of the types of selection bias.