# Correlation Analysis of Human Immunological Indicators and Nosocomial Infections, Along With Evaluation Value for Prognosis

## TL;DR

This study identifies immune markers linked to hospital-acquired infections in emergency patients and evaluates their role in predicting prognosis.

## Contribution

The study introduces a nomogram model using immunological indicators to predict nosocomial infection risk and prognosis in emergency patients.

## Key findings

- High NK cell count and high Charlton score are independent risk factors for nosocomial infection.
- Low CD3+CD4+ and CD3+CD8+ T lymphocyte counts are protective against nosocomial infection.
- The nomogram model achieved a high predictive accuracy (AUC of 0.920) for infection risk.

## Abstract

Objective: This study aimed to analyze the relevant risk factors for nosocomial infection (NI) in patients who were admitted to an emergency department, explore the correlation between each influencing factor and the risk of NI, and evaluate the application value of immunological indicators on the patient prognosis, all of which can provide reference for clinical guidance.

Methods: We prospectively enrolled 128 patients meeting the inclusion criteria who visited the emergency department of Dongzhimen Hospital, Beijing University of Chinese Medicine, from January 1 to December 31, 2019. Basic information and serum samples were collected from the patients, and flow cytometry was used. T lymphocyte subgroups, CD3+CD4+and CD3+CD8+, and natural killer (NK) cells were measured. Patients were divided into infection group and control group according to whether nosocomial infection occurred within 48 h of admission. Age, gender, type of disease, APACHE II score, Charlton score, T lymphocyte subtypes, and NK cell values were compared, and a logistic multivariate regression analysis was conducted. A multifactor regression analysis was performed on various risk factors. The nomogram website was used to draw a nomogram model of meaningful indicators, and the receiver-operating characteristic (ROC) curve was based on experimental results.

Results: Logistics multivariate regression analysis showed the Charlton score and NK cell count were independent risk factors for nosocomial infection. Cell counts for subsets CD3+CD4+ and CD3+CD8+ were protective factors, and the OR value and 95% CI were 5.199 (1.933–13.983), 1.248 (1.055–1.475), 0.851 (0.790–0.916), and 0.832 (0.711–0.973), p < 0.05. respectively. Statistical significance was set at p < 0.05.The nomogram model suggested that the area under the curve for predicting the risk of nosocomial infection was 0.920 (0.872–0.967), p < 0.001.

Conclusion: Patients with low CD3+CD4+ and CD3+CD8+ T lymphocyte or high NK cell count as well as high Charlton score are more likely to have nosocomial infection. Then, we speculate that the risk of nosocomial infection within 48 h is also high for patients with underlying diseases and immune function that is affected and suppressed on admission, regardless of whether infection occurs during hospitalization.