We thank Miles et al. for their interest in our recent article examining the association of perioperative concentrations of neurofilament light and cognition after cardiac surgery. 1 In their letter, the authors raise the important question of whether kidney disease could confound the association of neurofilament light and cognitive dysfunction. As the authors discuss, the concentrations of blood biomarkers may be altered in patients with chronic kidney disease, 2 although the clinical relevance with respect to prediction of cognitive outcomes has not been established. 3 To address the question of potential confounding as suggested by the authors, we considered postoperative day 1 creatinine concentration (or the next available hospital creatinine if there was not a postoperative day 1 creatinine) as a potentially confounding variable. In the adjusted models (with or without multiple imputation) examining the association of change in neurofilament light with cognitive change from baseline at 1-year after surgery, we found no change in the inferences when postoperative creatinine was added to the model. These results suggest that altered clearance of neurofilament light due to kidney dysfunction does not confound the association of change in neurofilament light with cognitive change from baseline at 1-year after surgery.
Funding
This work was supported by grants from the National Institute on Aging (CB: K-76 AG057020, RF-1 AG072387), the National Heart Lung and Blood Institute (CH R-01 HL092259). Philanthropic support was also provided from the Lantry Family Foundation (AM).
Footnotes
Declaration of Interests
CB has consulted for and received grant funding from Medtronic.
CH is a consultant and provides lectures for Medtronic/Covidien, Inc (Boulder, CO).
CH is a consultant to Merck, Inc (Kenilworth, NJ)
CH has received funding from Edwards Lifesciences (Irvine CA)
Dr. Moghekar has contractual research support from Fujirebio Diagnostics Ltd in unrelated areas.
Dr. Moghekar has received funding from Silver Golub Tietell LLP (Stamford CT)
Prior Presentations: None
Contributor Information
Charles H. Brown, IV, Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
Charles W. Hogue, Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago IL, 60611.
Abhay Moghekar, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
References
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