In Reply Dr Powers asks whether surgery actually increased the risk of recurrent stroke or whether recurrent stroke would have occurred at comparable rates among patients not undergoing surgery. As highlighted by Powers, the natural course of stroke includes a time-dependent decline in risk of recurrent stroke also among patients not undergoing surgery.
To further investigate this question, we performed an analysis including all individuals aged 25 years or older drawn from the entire Danish background population between 2005 and 2011 and randomly assigned a fictive “surgery date.” We followed up individuals who were alive at that date and who had had a stroke within the previous 5 years but who did not have a surgical procedure performed within the proceeding 30-day period to determine their 30-day risk of recurrent stroke (n = 72 007; mean age, 72 [SD, 13] years; 53% men) and compared their risk with that of the population in our study.
Jørgensen ME, Gislason GH, Andersson C. Time Since Stroke and Risk of Adverse Outcomes After Surgery—Reply. JAMA. 2014;312(18):1930-1931. doi:10.1001/jama.2014.13428