Neurological Severity and Systemic Biochemical Markers in Relation to Transition to Oral Feeding in Chronic...

Background: Post-stroke dysphagia is associated with aspiration pneumonia, malnutrition, and poor functional outcomes. Although systemic biochemical abnormalities are common after stroke, their contribution to swallowing recovery and transition to oral feeding remains unclear. This study investigated the association of systemic biochemical markers with oral feeding transition and swallowing-related functional improvement in patients with chronic post-stroke dysphagia. Methods: This retrospective single-center study included 89 patients with chronic post-stroke dysphagia who received enteral nutrition between February 2023 and December 2025. Biochemical parameters and swallowing outcomes, assessed using the Functional Oral Intake Scale (FOIS) and Penetration-Aspiration Scale (PAS), were retrospectively analyzed. Changes between baseline (T0) and follow-up (T1) were calculated (Δ = T1 - T0). Multivariable logistic and linear regression analyses were performed to identify independent predictors of transition to oral feeding and improvement in aspiration severity. Results: Of the 89 patients, 52 (58.4%) achieved oral feeding. Significant improvements in swallowing function were observed following rehabilitation, as reflected by increased FOIS scores and decreased PAS-soft and PAS-liquid scores (all p < 0.001), together with reductions in CRP (C-reactive protein), D-dimer, white blood cell count, and neutrophil count (all p < 0.05). Patients who achieved oral feeding demonstrated greater improvements in PAS scores (both p < 0.001) and a divergent change in vitamin B12 levels (a decrease among those who transitioned versus an increase among those who remained enterally fed) (p = 0.049). In exploratory multivariable analyses, higher NIHSS (National Institutes of Health Stroke Scale) scores and lower baseline 25-hydroxyvitamin D levels were associated with a lower likelihood of transition to oral feeding (NIHSS OR = 0.78, p = 0.031; vitamin D OR (Odds ratio) = 1.12, p = 0.001), whereas baseline PAS-liquid score was not an independent predictor of transition. In the linear regression analysis of aspiration severity, baseline PAS-liquid score was the strongest predictor of ΔPAS-liquid (B = -0.527, p = 0.001), while lower baseline 25-hydroxyvitamin D was associated with less improvement (B = -0.021, p = 0.047). Given the limited sample size and the absence of correction for multiple comparisons, the biochemical associations should be interpreted as exploratory. Conclusions: In patients with chronic post-stroke dysphagia, transition to oral feeding was primarily associated with neurological severity, whereas improvement in aspiration severity was most strongly related to baseline aspiration burden. Lower baseline 25-hydroxyvitamin D showed exploratory associations with both outcomes. Because 25-hydroxyvitamin D did not change significantly during follow-up and the models were underpowered, this association should be regarded as hypothesis-generating rather than clinically established. These biochemical findings require confirmation in larger prospective studies.