Association of follow-up neutrophil-to-lymphocyte ratio and systemic inflammation response index with stroke-associated pneumonia and functional outcomes in cerebral hemorrhage patients: a case controlled study

Background: Neutrophil-to-lymphocyte ratio (NLR) and systemic inflammation response index (SIRI) at admission are independent diagnostic biomarkers in stroke-associated pneumonia (SAP). Our study aimed to investigate the association between NLR, SIRI, specifically follow-up NLR and SIRI, and SAP, as well as their relationship with functional outcomes. Materials and Methods: We retrospectively included 451 consecutive ICH patients from May 2017 to May 2019. We conducted univariate and multivariable analyses to identify the factors independently associated with SAP and poor functional outcomes. Results: Compared to 127 (28.16%) patients diagnosed with SAP, those without SAP had both lower baseline and follow-up NLR and SIRI values ( P <0.001). After adjustments, we found that baseline NLR (OR, 1.039 [95% CI, 1.003-1.077]; P =0.036) and follow-up NLR (OR, 1.054 [95% CI, 1.011-1.098]; P =0.012) were independently associated with SAP. The follow-up NLR was also associated with a higher mRS (OR, 1.124 [95% CI, 1.025-1.233]; P =0.013) and lower ADL-MBI score (OR, 1.167 [95% CI, 1.057-1.289]; P =0.002) at discharge. Multivariable analysis indicated that advanced age and nasogastric tube feeding were independently associated with SAP ( P <0.05). We constructed a dynamic nomogram to identify SAP risk. Further subgroup analysis revealed that baseline NLR (OR, 1.062 [95% CI, 1.007-1.120]; P =0.026) is independently associated with SAP in the nasogastric feeding group, while follow-up NLR (OR, 1.080 [95% CI, 1.024-1.139]; P =0.005) was associated with the occurrence of SAP in non-nasogastric feeding patients. Conclusions: We found elevated baseline and follow-up NLR values were associated with SAP occurrence, and increasing follow-up NLR indicated poor functional outcomes. Inflammatory markers at different stages may offer individualized guidance for patients receiving various treatments.