A study examining wound infections after incidental appendectomy recorded the ri
ID: 167015 • Letter: A
Question
A study examining wound infections after incidental appendectomy recorded the risk of wound infection in each exposure group and estimated the cumulative incidence. The relative risk (or risk ratio) is an intuitive way to compare the risks for the two groups. The table below shows the number of patients who had wound infections when an incidental appendectomy was done during a staging laparotomy for Hodgkins disease. Calculate the Cumulative incidence rates for each group and place your answers in the table. Next, calculate the RR for the problem and then interpret your findings for the infection control officer at your hospital.Explanation / Answer
Answer:
in this case, Cumulative incidence would provide an estimate of risk in Incidental Appendectomy. It can be calculated by dividing the number of patients that developed wound infection with total number of patients for respective cases (where patient underwent incidental Appendectomy and opted not to)
In this study the risk of wound infection in both the groups (had and not had incidental Appendectomy) can be estimated from the cumulative incidence.
Risk ratio can be calculated as:
Risk Ratio = CIe / CIu, where CIe = Cumulative Incidence for exposed group (that had incidental Appendectomy)
and CIu = Cumulative Incidence for the unexposed group (did not undergo incidental Appendectomy)
Therefore Risk Ratio = 9.84/2.22 = 4.43
Interpretation of findings for infection control officer: The risk ratio of 4.43 suggests that patients who underwent incidental Appendectomy had 4.43 times higher risk of getting a wound infection after surgery compared to the patients who did not undergo incidental Appendectomy.
Had Incidental Appendectomy Wound Infection No Wound Infection Total Cumulative Incidence Yes 19 174 193 =19/193 = 9.84% No 2 88 90 =2/90 = 2.22%Related Questions
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