Background: Depression is a leading cause of disability post-stroke. Nearly a third of stroke victims suffer from depression after event occurrence. Post-stroke depression hinders physical rehabilitation, decreases quality of life, and has a negative effect on long-term survivability. Inflammatory processes post-ischemic stroke are likely associated with the development of depression. The neutrophil-lymphocyte ratio (NLR) is a routinely available marker of systemic inflammation and could serve as a prognostic tool at hospital admission for post-stroke depression. The goal of this project was to determine the relationship between admission NLR and depression 30 and 90 days post-stroke.
Methods: 58 ischemic stroke patients were recruited from a regional primary stroke center and followed up to 90 days post stroke. NLR levels were drawn at Emergency Department admission and at 24 hours. The Quick Inventory for Depression Symptomology (QIDS) was used to measure depression symptoms at 24 hours, 30 days and 90 days post stroke. We scaled continuous variables by their standard deviation and used the Box-Cox or exponential transformation if the skew was greater than 0.5. An age-adjusted Pearson's correlation was utilized to assess bivariate relationships. Other methods used include Mann-Whitney-Wilcoxon test and Fisher's Exact test when appropriate to compare ischemic and non-stroke patients.
Results: Adjustments for age were included due to weak to strong correlations with various measures of NLR and QIDS. There is a statistically significant correlation between the baseline NLR and baseline QIDS (correlation = -0.54, p-value=0.013) and QIDS at 30 days (correlation=-0.67, p-value=0.028). NLR at 24 hours has a statistically moderate correlation with QID at 30 days (correlation=0.39, p-value=0.055) and QIDS at 90 days (correlation=0.36, p-value=0.134).
Conclusions: This preliminary study suggests that NLR at hospital admission could serve as a prognostic marker of post stroke depression at thirty days. Utilization of this marker in clinical practice for stroke care could identify high risk patients and result in earlier treatment of depression. Validation studies and preventative strategies will need to be explored in future studies.