Objective:

To investigate the association between neutrophil percentage-to-albumin ratio (NPAR) and chronic subdural hematoma (CSDH), and evaluate its discriminative efficacy.

Approach:

• Study Design: Retrospective analysis of clinical data from 87 CSDH patients and 130 healthy controls.
• Statistical Analysis: Logistic regression, ROC curves, bootstrap validation, VIF, and Hosmer-Lemeshow test were performed.
• Stratified Analysis: Assessing association robustness by age (<70 vs. ≥70 years) and sex.

Key Findings:

• NPAR was significantly higher in CSDH patients (15.31 ± 2.71 vs. 12.47 ± 1.97, P < 0.001).
• Multivariate analysis showed NPAR (OR = 1.88, 95% CI: 1.41–2.51, P < 0.001) was independently associated with CSDH.
• NPAR demonstrated optimal discriminative efficacy (AUC = 0.808, 95% CI: 0.747–0.868; sensitivity 71.3%, specificity 83.8%).
• Bootstrap-validated multivariate AUC was 0.914 (optimism-corrected 0.907).
• Progressive adjustment attenuated the NPAR OR by only 9.6%.

Interpretation:

Limitations:

• The association cannot be directly extrapolated as a clinically operational diagnostic threshold.
• Further validation is required in target screening populations.

Conclusion: