Biomarkers Capable to Early Predict Postoperative Complications: The Grail
We read the article by Rettig et al1 on correlation between systemic inflammation and adverse outcomes after major abdominal surgery with great interest. The authors tested the predictive performance of C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in a cohort of 137 patients. Focusing on IL-6 on POD1, the ROC curve identified an optimal cut-off of 432 pg/mL, which seems to be independently associated with complications in multivariate analysis. The authors concluded that a high level of IL-6 on POD1 was associated with complications and this may help to stratify patients. The identification of biomarkers capable to accurately predict complications during early postoperative phase remains a clear unmet need matter of debate. The study by Rettig et al collecting such a prospective cohort is therefore very important.
Unfortunately, the surgical approach laparoscopy or open was neither reported nor included in the analyses. As laparoscopy has been evidenced to reduce surgical stress response and postoperative complications,2,3 this would be an important element. Therefore, integrating the surgical approach in their multivariate analysis could possibly change the statistical significances, and the conclusion. Moreover, it would be interesting to know why the authors did focus on IL-6, which is not a marker used routinely in clinical practice. Some comments on the potential limitations regarding reproducibility of the test and its cost would be of additional interest.