In my team we do a study on a group of patients undergoing abdominal surgery and we evaluate the correlation between frailty amongst patients and complications.
Background knowledge:
We use a frailty-score (Clinical Frailty Score, CFS) where 1 is non-frail and 9 is severe frail. Patients are categorized into three groups (CFS 1-3, 4-6 and 7-9)
We score complications based upon a complication score taking into account severity of the complication (Clavien Dindo Score, CD1-5, where 1 is a minor complication, and 5 is death).
We want to examine data regarding the distribution of the complications regarding severity in the 3 different groups of frail patients.
One important point: 1 patient can suffer from many complications.
As so - we have 3 groups that can suffer from (multiple) events of different severity.
as an example a dummy-table
Which would mean that 80 complications graded CD3 was observed within the group CFS1-3 and 60 complications graded CD2 was observed in the group 7-9.
Questions:
Q1) how would you report data in the table?
thoughts:
if we report percentage complications related to the number of patients in each group we get percentages >100 and it is weird.
If we report complications as a percentage of the total number of complications in the group we do not take into account the different sizes of the groups.
I argue that we should report event-rates (Incdence rates) but would love to hear som feedback.
Q2) If we would like to evaluate data statistically - what kind of analysis would you prefer, taking into account the multiple events for a single patient? We would like to statistically show that there are difference between the groups (which we intuitively can see, but are uncertain as to what kind of analysis one should use here).
feel free to ask if anything stands unclear. I've tried to be as thorough as i could think off.
Kindly.
Thomas, Copenhagen.
