Neutrophil to Lymphocyte Ratio as a Predictor of Complicated Acute Diverticulitis: A Retrospective Cohort Study

Introduction Acute diverticulitis (AD) is present in 10-25% of patients with diverticular disease, being most common in sigmoid colon, with around 200.000 hospitalizations yearly . As much as one fifth of patients are younger than 50 at the moment of diagnosis and around 5% under the age of 40 .

Confirming the diagnosis requires the utilization of imaging studies, therefore, American Society of Colon and Rectal Surgeons (ASCRS) established that computed tomography (CT) is the standard method for the diagnosis of AD, with a sensitivity of 98% and a specificity of 99%. The tomographic findings vary according the severity of diverticular disease, which is categorized through a modified Hinchey classification system. Approximately 10-15% of AD patients may develop complications that imply the onset of abscesses, fistulas, stenosis, obstruction and/or perforation.

Recently, interest has been raised in the role of biomarkers in diverticular disease as non-invasive, reliable, inexpensive tools that may help in the early diagnosis of complicated AD, such as C-reactive protein (CRP), useful marker in the prediction of the level of inflammation and severity of AD.

In 2001 identified the neutrophil-lymphocyte ratio (NLR) as an inflammation marker in critical patients, defining as the absolute neutrophil count divided by the absolute lymphocyte count. Over the last decade, NLR effectiveness has been recognized in various pathologies, both benign and malignant; finding that the levels of neutrophils rise as a part of the inflammatory cascade, whereas lymphocytes diminish during sepsis, making a novel subclinical biomarker with a prognostic value in oncological, cardiovascular and infectious diseases, among others. The NLR may be obtained from the blood count data, which represents a lower cost regarding other known biomarkers. It was also demonstrated that high values of NLR are associated with severe abdominal infections and worse outcomes, reason why it started to be applied as a predictor to evaluate results in surgical patients.

Currently, the debate on usefulness of NLR as a predictor of complications in AD remains open, specially, the relation to the severity of the disease, the clinical impact and the necessity of minimally invasive or emergency surgical procedures.