Annualised complication rate

#1
Hello,
I audited my clinical practice of ventriculo-peritoneal shunts. These can block any time after they have been inserted. I have audited my practice of 2 years and 7 months. So now I have blockage rate for this period. Is there a way to calculate the annualised results from the the cumulative results of 2 years and 7 months. Many thanks.
 

hlsmith

Less is more. Stay pure. Stay poor.
#2
I think what you want is to just divide your count of clotted procedures by number of months, 31, then times that number by 12.

I wonder, is this is the best rate or if you should report it by procedures, so number of clotted procedures / # procedures. This way the denominator comes into play. Otherwise you can say you have 56 clots per year, and a person doesn't know if you have 56 procedures per year or 10,000, the risk isn't known. Also, you need to make sure a person is only counted once, or this may need to be controlled for. So if a person can have more than one procedure and contribute more than one observation, then they are correlated with themselves (if I clotted once I may clot again or you all may intervene more to prevent the imminent second clot.