Neutrophil-to-Lymphocyte Ratio as a Marker of Diabetic Ketoacidosis Severity in Type 1 Diabetes Mellitus: A Retrospective Study

Background: Diabetic ketoacidosis (DKA) is a serious complication of type 1 diabetes mellitus (T1DM) characterized by hyperglycemia, metabolic acidosis, and ketonemia. Early assessment of disease severity is crucial for effective management and better patient outcomes. Recent research has suggested that hematological markers, especially the neutrophil-to-lymphocyte ratio (NLR), can serve as valuable indicators of systemic inflammation and disease severity. This study aimed to evaluate the association between the NLR and DKA severity and to identify clinically relevant cutoff thresholds. Methods: This retrospective study reviewed the records of 170 patients with T1DM and DKA admitted to King Fahad Specialist Hospital, Buraydah, Saudi Arabia, between 2023 and 2025. Demographic, clinical, and laboratory data, including complete blood counts for NLR calculations at admission, were collected. DKA severity was classified as mild, moderate, or severe based on pH and bicarbonate levels. Results: The mean patient age was 21.7 years (standard deviation (SD): 8.74), and 88 (51.8%) of the patients were female. Moderate DKA was present in 102 (60%) of the patients, while severe DKA was present in 20 (11.8%). DKA severity was correlated with higher NLR (p=0.035), random blood glucose (p=0.001), and white blood cell count (p=0.031) and inversely correlated with pH (p<0.001) and bicarbonate level (p<0.001). Conclusions: NLR was significantly associated with DKA severity in T1DM. Although the demographic and clinical variables lacked predictive value, an elevated NLR correlated with key metabolic abnormalities. Despite its modest diagnostic accuracy, NLR remains a practical early marker of disease severity in DKA.