Complete blood count (CBC)-derived indices at admission and short-term outcomes in ICU patients: a retrospective study

Abstract

Introduction: CBC parameters relay comprehensive information about the cellular components of the blood (erythrocytes, leucocytes, and platelets) and get affected by acute and chronic physiological and pathological stresses, as evidenced by the derangements in their parameters. Clinicians have advocated for indices derived by combining the parameters of the CBC and suggested that these parameters can predict outcomes in various inflammatory situations. We aimed to investigate the possible correlation of these indices with short-term outcomes (mortality, duration of ICU, and hospital stay) in ICU-admitted cases in our study. Patients and methods: We conducted a retrospective analytical study among patients admitted to the general ICU of Nepal Medical College, Kathmandu. Data collection was performed using records in the ICU register and electronic database. Records of at-admission CBC reports and other information pertaining to the eligible participants were retrieved. Various indices were calculated from the CBC parameters and analyzed for their associations with short-term outcomes. Results: Among 486 ICU patients, 56% were male, and the mean age was 52.95 ± 18.85 years. The average length of the ICU stay was 2 days (1–4), and the total hospital stay was 6 days (3–10), with a 19.7% ICU death rate. Older age (≥68 years), low hemoglobin level (<8 g/dl), and the presence of sepsis with septic shock at admission were the strongest predictors of in-ICU mortality. NLR had some predictive power for in-ICU mortality with an AUC value of 0.55. While TLC alone did not differ significantly between survivors and non-survivors. Conclusion: Among CBC-derived parameters, the neutrophil-to-lymphocyte ratio had some predictive value for all-cause in-ICU mortality. Further research among etiology or diagnosis-specific cohorts of ICU patients that demonstrate dynamic changes in CBC-derived parameters may be needed to elucidate their role in patient outcomes.