Higher neutrophil-to-lymphocyte ratio, mean platelet volume, and platelet distribution width are associated with postoperative delirium in patients undergoing esophagectomy: a retrospective observational study

Platelet Dynamics in Neurodegenerative Disorders: Investigating the Role of Platelets in Neurological Pathology

Background: Neurological disorders, particularly those associated with aging, pose significant challenges in early diagnosis and treatment. The identification of specific biomarkers, such as platelets (PLTs), has emerged as a promising strategy for early detection and intervention in neurological health. This systematic review aims to explore the intricate relationship between PLT dynamics and neurological health, focusing on their potential role in cognitive functions and the pathogenesis of cognitive disorders. Methods: Adhering to PRISMA guidelines, a comprehensive search strategy was employed in the PubMed and Scholar databases to identify studies on the role of PLTs in neurological disorders published from 2013 to 2023. The search criteria included studies focusing on PLTs as biomarkers in neurological disorders, their dynamics, and their potential in monitoring disease progression and therapy effectiveness. Results: The systematic review included 104 studies, revealing PLTs as crucial biomarkers in neurocognitive disorders, acting as inflammatory mediators. The findings suggest that PLTs share common features with altered neurons, which could be utilised for monitoring disease progression and evaluating the effectiveness of treatments. PLTs are identified as significant biomarkers for detecting neurological disorders in their early stages and understanding the pathological events leading to neuronal death. Conclusions: The systematic review underscores the critical role of PLTs in neurological disorders, highlighting their potential as biomarkers for the early detection and monitoring of disease progression. However, it also emphasises the need for further research to solidify the use of PLTs in neurological disorders, aiming to enhance early diagnosis and intervention strategies.

Association between increased systemic immune-inflammation index and postoperative delirium in older intertrochanteric fracture patients

BACKGROUND AND PURPOSE

The systemic immune-inflammation index (SII), a novel inflammation index derived from the counts of circulating platelets, neutrophils and lymphocytes, has been studied in the treatment of acute cancer and ischemic stroke (AIS). However, the clinical value of the SII in postoperative delirium patients has not been further investigated. The purpose of our research was to study the incidence and preoperative risk factors for postoperative delirium (POD) and verify whether the SII could serve as a potential marker for POD in older intertrochanteric fracture patients. Finally, we created a novel nomogram for predicting POD in older patients with intertrochanteric fractures.

METHODS

We enrolled elderly patients with intertrochanteric fractures who underwent proximal femoral nail antirotation (PFNA) between February 2021 and April 2023. Univariate and multivariate logistic analyses were subsequently performed to confirm the risk factors and construct a nomogram model.Calibration curve and clinical decision curve analysis (DCA) were used to assess the model's fitting performance. The performance of the nomogram was evaluated for discrimination, calibration, and clinical utility.

RESULTS

A total of 293 patients were eligible for inclusion in the study, 25.6% (75/293) of whom had POD. The POD patients had higher SII values than the non-POD patients. The SII was strongly correlated with POD in older intertrochanteric fracture patients, and the optimal cutoff value was 752.6 × 109. Multivariate analysis revealed that age, diabetes, total albumin, SII > 752.6 × 109 and a CRP > 20.25 mg/L were independent risk factors for POD patients. By incorporating these 5 factors, the model achieved a concordance index of 0.745 (95% CI, 0.683-0.808) and had a well-fitted calibration curve and good clinical application value.

CONCLUSION

The SII is a simple and valuable biomarker for POD, and the new nomogram model can be used to accurately predict the occurrence of POD. They can be utilized in clinical practice to identify those at high risk of POD in older intertrochanteric fracture patients.

Effects of a False Window on the Change of Cognitive Function in Patients Admitted to a Neurological Ward

False windows can display a variety of outdoor scenery in rooms without real windows. We aimed to assess the effects of three different hospital beds on the change in the frontal assessment battery scores in patients aged ≥ 20-year-old admitted in our neurological ward. We included 24 patients on the window side, 12 patients on the aisle side with a false window, and 12 patients on the aisle side without a false window. There were no statistical differences in the change of cognitive function among the three hospital beds. Only the length of hospital stay was a significant associated factor.

Association of preoperative neutrophil-lymphocyte ratios with the emergence delirium in pediatric patients after tonsillectomy and adenoidectomy: an observational prospective study

PURPOSE

The study aimed to investigate potential risk factors for emergence delirium (ED) in pediatric patients after tonsillectomy and adenoidectomy (T&A).

METHODS

This prospective, single-center observational study enrolled children aged 3-7 years who underwent T&A under general anesthesia. ED was assessed according to DSM-IV or V criteria. Receiver operating characteristic curve analysis was performed to evaluate the predicative and cut-off values of risk factors, including age, preoperative anxiety level, postoperative pain and neutrophil-lymphocyte ratio (NLR) for ED. Univariate and multivariate logistic regression analyses were performed to investigate risk factors for ED.

RESULTS

94 pediatric patients who underwent T&A were enrolled and 19 developed ED (an incidence of 25.3%). Receiver operating characteristic analysis indicated that preoperative NLR was a significant predictor of ED with a cut-off value of 0.8719 and an area under the curve (AUC) of 0.671 (95% confidence interval (CI) 0.546-0.796, P = 0.022). Preoperative NLR (< 0.8719) and postoperative pain were independent risk factors associated with ED (odds ratio: 0.168, 95% CI 0.033-0.858, P = 0.032; odds ratio: 7.298, 95% CI 1.563-34.083, P = 0.011) according to multivariate logistic regression analysis.

CONCLUSIONS

Preoperative NLR level and postoperative pain were independent risk factors for ED in pediatric patients undergoing T&A.

Association between preoperative neutrophil-lymphocyte ratio, uric acid, and postoperative delirium in elderly patients undergoing degenerative spine surgery

PURPOSE

There are few reports regarding the association between the neutrophil-lymphocyte ratio (NLR), uric acid, and the development of postoperative delirium (POD) in patients who are undergoing spine surgeries. We investigated the associations between the NLR, uric acid as a natural antioxidant, and POD in elderly patients undergoing degenerative spine surgery.

PATIENTS AND METHODS

This was a single-center, observational, and retrospective study conducted in Japan. We enrolled 410 patients who underwent degenerative spine surgery. POD was diagnosed after the surgeries by psychiatrists, based on the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). We performed a multivariable logistic regression analysis to clarify whether the NLR and uric acid values were associated with the development of POD in the patients.

RESULTS

129 of the 410 patients were excluded from the analysis. Of the 281 patients (137 females, 144 males), 32 patients (11.4%) were diagnosed with POD. The multivariable logistic regression analysis revealed that the preoperative uric acid level (adjusted odds ratio [aOR]: 0.67, 95% confidence interval [CI]: 0.49-0.90, p = 0.008) and age (aOR: 1.09, 95% CI: 1.02-1.16, p = 0.008) were significantly associated with POD. The preoperative NLR (aOR: 0.82, 95% CI: 0.60-1.13, p = 0.227) and antihyperuricemic medication (aOR: 0.97, 95% CI: 0.24-3.82, p = 0.959) were not significantly associated with POD.

CONCLUSION

Our results demonstrated that in elderly patients undergoing degenerative spine surgery, the preoperative NLR was not significantly associated with POD, but a lower preoperative uric acid value was an independent risk factor for developing POD. Uric acid could have a neuroprotective impact on POD in patients with degenerative spine diseases.

The Perioperative Frontal Relative Ratio of the Alpha Power of Electroencephalography for Predicting Postoperative Delirium After Highly Invasive Surgery: A Prospective Observational Study

BACKGROUND

We investigated the associations between postoperative delirium (POD) and both the relative ratio of the alpha (α)-power of electroencephalography (EEG) and inflammatory markers in a prospective, single-center observational study.

METHODS

We enrolled 84 patients who underwent radical cancer surgeries with reconstruction for esophageal cancer, oral floor cancer, or pharyngeal cancer under total intravenous anesthesia. We collected the perioperative EEG data and the perioperative data of the inflammatory markers, including neutrophil gelatinase-associated lipocalin, presepsin, procalcitonin, C-reactive protein, and the neutrophil-lymphocyte ratio (NLR). The existence of POD was evaluated based on the Intensive Care Delirium Screening Checklist. We compared the time-dependent changes in the relative ratio of the EEG α-power and inflammatory markers between the patients with and without POD.

RESULTS

Four of the 84 patients were excluded from the analysis. Of the remaining 80 patients, 25 developed POD and the other 55 did not. The relative ratio of the α-power at baseline was significantly lower in the POD group than the non-POD group (0.18 ± 0.08 vs 0.28 ± 0.11, P < .001). A time-dependent decline in the relative ratio of α-power in the EEG during surgery was observed in both groups. There were significant differences between the POD and non-POD groups in the baseline, 3-h, 6-h, and 9-h values of the relative ratio of α-power. The preoperative NLR of the POD group was significantly higher than that of the non-POD group (2.88 ± 1.04 vs 2.22 ± 1.00, P < .001), but other intraoperative inflammatory markers were comparable between the groups. Two multivariable logistic regression models demonstrated that the relative ratio of the α-power at baseline was significantly associated with POD.

CONCLUSIONS

Intraoperative frontal relative ratios of the α-power of EEG were associated with POD in patients who underwent radical cancer surgery. Intraoperative EEG monitoring could be a simple and more useful tool for predicting the development of postoperative delirium than measuring perioperative acute inflammatory markers. A lower relative ratio of α-power might be an effective marker for vulnerability of brain and ultimately for the development of POD.

Neutrophil to lymphocyte ratio and platelet to lymphocyte ratio as prognostic predictors for delirium in critically ill patients: a systematic review and meta-analysis

INTRODUCTION

In this systematic review and meta-analysis, we aim to analyze the current literature to evaluate neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) values among critically ill patients who develop delirium as compared to those who do not.

METHODS

PubMed, Web of Science, and Scopus were used to conduct a systematic search for relevant publications published before June 12, 2022. The Newcastle-Ottawa scale was used for quality assessment. Because a significant level of heterogeneity was found, we used the random-effects model to generate pooled effects.

RESULTS

Twenty-four studies including 11,579 critically ill patients, of whom 2439 were diagnosed with delirium, were included in our meta-analysis. Compared with the non-delirious group, the delirious group's NLR levels were significantly higher (WMD = 2.14; CI 95% = 1.48-2.80, p < 0.01). In the subgroup analysis according to the type of critical condition, the NLR levels in patients of delirious group were significantly more than those of non-delirious group in studies on POD, PSD and PCD (WMD = 1.14, CI 95% = 0.38-1.91, p < 0.01, WMD = 1.38, CI 95% = 1.04-1.72, p < 0.001, and WMD = 4.22, CI 95% = 3.47-4.98, p < 0.001, respectively). However, compared with the non-delirious group, the delirious group's PLR levels were not significantly different (WMD = 1.74; CI 95% = -12.39-15.86, p = 0.80).

CONCLUSION

Our findings support NLR to be a promising biomarker that can be readily integrated into clinical settings to aid in the prediction and prevention of delirium.

Risk factors and consequences of post-esophagectomy delirium: a systematic review and meta-analysis

Post-operative delirium (POD) is a state of mental and neurocognitive impairment characterized by disorientation and fluctuating levels of consciousness. POD in the context of esophageal surgery may herald serious and potentially life-threatening post-operative complications, or conversely be a symptom of severe underlying pathophysiologic disturbances. The aim of the present systematic review and meta-analysis is to explore risk factors associated with the development of POD and assess its impact on post-operative outcomes. A systematic literature search of the MedLine, Web of Science, Embase and Cochrane CENTRAL databases and the clinicaltrials.gov registry was undertaken. A random-effects model was used for data synthesis with pooled outcomes expressed as Odds Ratios (OR), or standardized mean differences (WMD) with corresponding 95% Confidence Intervals. Seven studies incorporating 2449 patients (556 with POD and 1893 without POD) were identified. Patients experiencing POD were older (WMD 0.29 ± 0.13 years, P < 0.001), with higher Charlson's Comorbidity Index (CCI; WMD 0.31 ± 0.23, P = 0.007) and were significantly more likely to be smokers (OR 1.38, 95% CI 1.07-1.77, P = 0.01). Additionally, POD was associated with blood transfusions (OR 2.08, 95% CI 1.56-2.77, P < 0.001), and a significantly increased likelihood to develop anastomotic leak (OR 2.03, 95% CI 1.25-3.29, P = 0.004). Finally, POD was associated with increased mortality (OR 2.71, 95% CI 1.24-5.93, P = 0.01) and longer hospital stay (WMD 0.4 ± 0.24, P = 0.001). These findings highlight the clinical relevance and possible economic impact of POD after esophagectomy for malignant disease and emphasize the need of developing effective preventive strategies.

Systemic immune-inflammation index predicts postoperative delirium in elderly patients after surgery: a retrospective cohort study

Background

Postoperative delirium (POD) is a common complication among elderly patients after surgery. It is unclear whether the systemic immune-inflammation index (SII) can be a predictor of POD. We explored the prognostic value of the SII in predicting POD in elderly patients undergoing non-neurosurgery and non-cardiac surgery in a large retrospective cohort.

Methods

We enrolled elderly patients undergoing non-neurosurgery and non-cardiac surgery between January 2014 and August 2019. Univariate and multivariate logistic regression analyses were performed to explore the correlation between POD and the SII value as both a continuous and categorical variable. Then, propensity score matching (PSM) analysis was applied to eliminate the confounding effect of covariates and prove our results. Subgroup analyses were then performed to discover the association between the SII and POD in different subgroups.

Results

A total of 29,608 patients with a median age of 70 years (IQR: 67–74) were enrolled in the retrospective cohort. The cut-off value of the SII was 650, which was determined by the receiver operating characteristic (ROC) curve. The ORs of an SII value > 650 was 2.709 (95% CI:2.373–3.092, P < 0.001), 1.615 (95% CI:1.384–1.882, P < 0.001), 1.855 (95% CI:1.602–2.146, P < 0.001), and 1.302 (95% CI:1.106–1.531, P = 0.001) for prediction of POD in univariate model and three multivariate regression models. After PSM, the OR of an SII value > 650 was 1.301 (95% CI: 1.062–1.598, P = 0.011). The subgroup analysis indicated that the SII indicates a significantly increased risk of POD in patients with Hb < 130 g/L, 4*10⁹/L < WBC ≤ 10*10⁹/L, albumin < 39 g/L, or duration of MAP < 60 mmHg ≥ 5 min. The SII was found to be a useful prognostic predictor of POD for patients of different ages, sexes, and ASA classifications.

Conclusions

The SII had a predictive value for POD in patients undergoing non-neurosurgery and non-cardiac surgery. As an index generated from routine blood tests, the SII has advantages regarding cost and time. After further validation, the SII may provide a new option for POD prediction.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-03418-4.

Challenges in the Detection of Clinically Useful Biomarkers for the Diagnosis of Delirium in Older People in the Emergency Department-A Case-Control Study

Background: The identification of biomarkers associated with delirium in the emergency department could contribute to the understanding, prediction and diagnosis of this disorder. The present study was carried out to identify biomarkers included in easily and quickly obtained standard blood examinations in older patients with delirium in the emergency department. Methods: A case–control study was carried out in the emergency department of Francesc de Borja Hospital (Gandía, Valencia, Spain). Older adults (≥65 years of age) diagnosed with delirium (n = 128) were included. Cases due to alcohol or substance abuse were excluded. Controls were selected on a randomized basis from the remaining patients (n = 128). All laboratory test parameters included in the routine blood and urine tests of the emergency department were collected. Results: The mean age of the patients was 81.24 ± 7.51 years, and 56.2% were males, while the mean age of the controls was 78.97 ± 7.99 years, and 45.3% were males. Significant differences were found between the cases and controls in relation to the following parameters: urea 43 (32–58) mg/dL versus 50 (37–66) mg/dL, respectively; neutrophils 69.6 (62.05–78.75)% versus 75.5 (65.1–83.2)%; monocytes 8.7 (7–10.4)% versus 7.6 (5.5–9.2)%; platelets 213 (159–266) × 10⁹/L versus 224 (182–289) × 10⁹/L; neutrophil–lymphocyte ratio 3.88 (2.45–7.07) versus 5 (2.75–8.83); platelet–lymphocyte ratio 281.4 (210–360) versus 357.1 (257.8–457.1); and mean platelet volume 10.6 (10–11.5) fl versus 10.4 (9.67–10.9) fl. Although the mean values were above desirable levels in both groups, they were higher for most parameters in the control group. No significant differences were observed in C-reactive protein concentration (9.99 (1.69–51) mg/L versus 12.3 (3.09–65.97) mg/L). Conclusions: The identification of delirium biomarkers poses difficulties due to the urgent nature of the disorders found in older people admitted to the emergency department. Research in this field is needed, since it would allow early identification and treatment of delirium.

Preoperative Inflammatory Markers and the Risk of Postoperative Delirium in Patients Undergoing Lumbar Spinal Fusion Surgery

We investigated the possible associations between postoperative delirium (POD) and routinely available preoperative inflammatory markers in patients undergoing lumbar spinal fusion surgery (LSFS) to explore the role of neuroinflammation and oxidative stress as risk factors for POD. We analyzed 11 years’ worth of data from the Smart Clinical Data Warehouse. We evaluated whether preoperative inflammatory markers, such as the neutrophil-to-lymphocyte ratio (NLR), the monocyte-to-lymphocyte ratio (MLR), and the CRP-to-albumin ratio (CAR), affected the development of POD in patients undergoing LSFS. Of the 3081 subjects included, 187 (7.4%) developed POD. A significant increase in NLR, MLR, and CAR levels was observed in POD patients (p < 0.001). A multivariate analysis showed that the second, third, and highest quartiles of the NLR were significantly associated with the development of POD (adjusted OR (95% CI): 2.28 (1.25−4.16], 2.48 (1.3−4.73], and 2.88 (1.39−5.96], respectively). A receiver operating characteristic curve analysis showed that the discriminative ability of the NLR, MLR, and CAR for predicting POD was low, but almost acceptable (AUC (95% CI): 0.60 (0.56−0.64], 0.61 (0.57−0.65], and 0.63 (0.59−0.67], respectively, p < 0.001). Increases in preoperative inflammatory markers, particularly the NLR, were associated with the development of POD, suggesting that a proinflammatory state is a potential pathophysiological mechanism of POD.

Higher neutrophil-lymphocyte ratio is associated with depressive symptoms in Japanese general male population

Relationships between the neutrophil–lymphocyte ratio (NLR) and/or the platelet-lymphocyte ratio (PLR) and neuroinflammatory diseases have been reported. Depression is also associated with neuroinflammation. Here, we determined the association between the NLR, PLR, and depressive symptoms. This cross-sectional study is a secondary analysis of the data of the Iwaki Health Promotion Project 2017. We analyzed the characteristics and laboratory data of 1,015 Japanese subjects (597 females, 408 males) including their NLR and PLR values. We assigned the subjects with a Center for Epidemiologic Studies Depression Scale (CES-D) score ≥ 16 to the depressive symptoms group. We performed a multivariate logistic regression analysis to determine whether the NLR and/or PLR were associated with depressive symptoms (CES-D ≥ 16). Two hundred subjects (19.7%; 122 [20.4%] females, 78 [19.1%] males) were assigned to the depressive symptoms group. There were significant differences between the non-depressive symptoms and depressive symptoms groups in the NLR [median (25th to 75th percentile): 1.54 (1.24, 1.97) vs. 1.76 (1.32, 2.37), P = 0.005] and the PLR [median (25th to 75th percentile): 123.7 (102.0, 153.9) vs. 136.8 (107.0, 166.5), P = 0.047] in males, but not in females. The multivariate logistic regression analysis demonstrated that the NLR was significantly associated with depressive symptoms in males (adjusted odds ratio: per 1 increase, 1.570; 95% confidence interval: 1.120–2.220; P = 0.009). In conclusion, our findings indicate that higher NLR may be associated with depressive symptoms in males.

White-Cell Derived Inflammatory Biomarkers in Prediction of Postoperative Delirium in Elderly Patients Undergoing Surgery for Lower Limb Fracture Under Non-General Anaesthesia

Purpose

The aim of this study was to investigate whether white-cell derived biomarkers could serve as potential markers in prediction of postoperative delirium (POD) after lower limb fracture.

Patients and Methods

Elderly patients with surgery for lower limb fracture under non-general anaesthesia were included. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and platelet-to-white cell ratio (PWR), which were most recently measured preceding surgery and measured within 24h after surgery, were calculated. Delirium was measured with Confusion Assessment Method (CAM) once daily from preoperative day 1 to postoperative day 3 or hospital discharge.

Results

The incidence of POD was 32.6% (60/184). Between patients with and those without POD, there were significant differences in preoperative hematological biomarkers (neutrophil count, lymphocyte count, NLR and PWR) and postoperative hematological biomarkers (white cell count, neutrophil count, lymphocyte count, NLR, PLR and PWR). More obvious changes before and after operation for NLR, PLR and C-reactive protein (CRP) were found in patients with POD. Multivariate logistic regression showed that benzodiazepines (OR, 7.912; 95% CI, 1.884–33.230; p = 0.005), change of CRP (OR, 1.017; 95% CI, 1.007–1.027; p = 0.001) and postoperative NLR (OR, 1.358; 95% CI, 1.012–1.823; p = 0.041) were associated with POD. When the changes of NLR, PLR and PWR entered multivariate logistic regression, older age (OR, 1.073; 95% CI, 1.001–1.149; p = 0.046), benzodiazepines (OR, 6.811; 95% CI, 1.652–28.081; p = 0.008), greater change of CRP (OR, 1.015; 95% CI, 1.006–1.023; p = 0.001) and greater change of NLR (OR, 1.266; 95% CI, 1.035–1.549; p = 0.022) were associated with increased risk of POD. Postoperative NLR had high accuracy to predict POD with area under curve (AUC) of 0.790 (95% CI 0.708 to 0.872).

Conclusion

Age, benzodiazepines, postoperative NLR, change of NLR and change of CRP were independent predictable markers for POD in elderly patients undergoing surgery for lower limb fracture under non-general anaesthesia. Early postoperative NLR may help to recognize POD as soon as possible.

Higher Neutrophil to Lymphocyte Ratio at Admission is Association with Post-PCI Depressive Symptoms in Patients with ACS

BACKGROUND

Depression and elevated blood biomarkers of inflammation are common in patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI). Neutrophil to lymphocyte ratio (NLR) is an indicator of peripheral inflammation and has been proved to be associated with both ACS and depression.

PURPOSE

Our aim was to evaluate the possible association between NLR at admission and post-PCI depressive symptoms at 1 month.

PATIENTS AND METHODS

A total of 224 patients with ACS who underwent PCI for the first time were recruited and completed 1-month follow-up. The 24-item Hamilton Depression Scale (HAMD-24) was used to measure depressive symptoms at 1 month after PCI. Logistic regression was used to analyze the relationship between different NLR levels and post-PCI depressive symptoms. A receiver operating characteristic (ROC) curve analysis was performed to assess the value of NLR for predicting post-PCI depressive symptoms and to determine its critical value.

RESULTS

Of the 224 enrolled patients, 52 (23.2%) patients were diagnosed with depressive symptoms at 1 month after PCI. Patients with depressive symptoms showed significantly higher level of NLR at admission than patients without depressive symptoms (4.33 (3.26, 7.01) vs 2.57 (1.72, 3.91), P < 0.001). The proportion of depressive symptoms in post-PCI patients increases progressively along with NLR quartile. In the results of multivariate-adjusted logistic regression analysis, the odds ratio (OR) of post-PCI depressive symptoms was 12.028 (95% CI, 2.642-54.752) for the lowest quartile of NLR compared with the highest quartile. According to the receiver operating characteristic curve (ROC), the area under the curve (AUC) for predicting post-PCI depressive symptoms was 0.716 (95% CI, 0.641-0.791; P < 0.001), and the optimal cutoff of NLR levels was 3.235 (sensitivity: 76.9%, specificity: 66.9%).

CONCLUSION

Higher NLR levels at admission were associated with post-PCI depressive symptoms at 1 month, suggesting that NLR might be useful inflammatory markers to predict post-PCI depressive symptoms at 1 month.

Prospective Analysis Between Neutrophil-to-Lymphocyte Ratio on Admission and Development of Delirium Among Older Hospitalized Patients With COVID-19

Objective: To examine any prospective association between neutrophil-to-lymphocyte ratio (NLR) at hospital admission and subsequent delirium in older COVID-19 hospitalized patients comparing by sex and age groups. Methods: The sample consisted of 1,785 COVID-19 adult inpatients (minimum sample size required of 635 participants) admitted to a public general hospital in Madrid (Spain) between March 16th and April 15th, 2020. Variables were obtained from electronic health records. Binary logistic regression models were performed between baseline NLR and delirium adjusting for age, sex, medical comorbidity, current illness severity, serious mental illness history and use of chloroquine and dexamethasone. An NLR cut-off was identified, and stratified analyses were performed by age and sex. Also, another biomarker was tested as an exposure (the systemic immune-inflammation index -SII). Results: 55.3% of the patients were men, with a mean age of 66.8 years. Roughly 13% of the patients had delirium during hospitalization. NLR on admission predicted subsequent delirium development (adjusted OR = 1.02, 95 percent CI: 1.00-1.04, p = 0.024). Patients between 69 and 80 years with NLR values > 6.3 presented a twofold increased risk for delirium (p = 0.004). There were no sex differences in the association between baseline NLR and delirium (p > 0.05) nor SII predicted delirium development (p = 0.341). Conclusion: NLR is a good predictor of delirium during hospitalization, especially among older adults, independently of medical comorbidity, illness severity, and other covariates. Routine blood tests on admission might provide valuable information to guide the decision-making process to be followed with these especially vulnerable patients.