LAUSR

We read with interest the article by Walker et al. on the role of several biomarkers, including the neutrophil-to-lymphocyte ratio (NLR), in predicting anastomotic dehiscence (AD). We recently evaluated the role of NLR in this setting with a case-match approach, and we obtained similar results. In our study, the archives of the surgical units involved were searched, and 44 patients who had a postoperative clinically manifested AD from 2012 through 2017 were enrolled. Subsequently, a control group with a rigorous matching in terms of sex, age, disease location, American Society of Anesthesiologists score, body mass index and surgical approach was retrieved. In cancer cases, we matched also the stage of the disease, and in those with rectal cancer, the distance from the anal verge. The NLR before the operation, and in the first and fourth post-operative days was calculated. No significant differences were found in the median values of NLR between the groups before surgery and in the first post-operative day. At the fourth post-operative day, the median NLR value was significantly higher in patients with AD, in comparison to those without (8.8, interquartile range (IQR): 5.37–11.87 versus 5.50, IQR: 3.40–7.00). The area under the curve (AUC) was lower than that obtained by Walker et al.: 0.697 (95% confidence interval (CI): 0.581–0.797). The best cutoff value in our study was 8.7, with sensitivity and specificity 52% (95% CI: 33.5–69.2) and 88% (95% CI: 74.9–96.1), respectively, while in the study of Walker et al. the best cutoff value was 6.18, with a sensitivity of 100% and a specificity of 61.8%. Our study, performed with a different approach, confirms the potential usefulness of NLR measured at the fourth post-operative day in predicting AD, but its diagnostic accuracy needs to be further investigated.