Globally, acute ischemic stroke (AIS) persists as a significant driver of both mortality and prolonged disability. Reliable biomarkers for predicting stroke outcomes must be identified to improve clinical decision-making. Residual cholesterol (RC) and RC inflammatory index (RCII) have been proposed as potential biomarkers, although their precise prognostic significance in stroke remains unclear. This research sought to examine the predictive value of RCII and RC in estimating extent of neurological impairment, assessed using the National Institutes of Health Stroke Scale (NIHSS), and functional recovery, evaluated using the three-month modified Rankin Scale (mRS), among individuals diagnosed with AIS. The study enrolled 775 individuals diagnosed with AIS. RC and RCII were derived and subsequently grouped into quartiles for analysis. The associations between RCII, RC, NIHSS, and the three-month mRS were investigated using multivariable logistic regression analysis. Subpopulation analysis, inflection point analysis, generalized additive models (GAM), and receiver operating curve (ROC) analyses were utilized to evaluate the ability of these biomarkers to predict outcomes and to identify their optimal cutoff points. RCII demonstrated a significant relationship with unfavorable functional prognosis, with participants belonging to the top quartile of RCII levels having almost double the risk of poor outcomes compared to those in the lowest quartile. (odds ratio [OR] = 1.98, 95% confidence interval [CI]; 1.20–3.26, P = 0.0071). RC showed no significant association with the NIHSS or three-month mRS (P > 0.05). ROC analysis demonstrated that the RCII exhibited moderate discriminatory power in predicting poor three-month outcomes (AUC = 0.641, 95% CI; 0.595–0.688), whereas RC demonstrated modest predictive performance (AUC = 0.519, 95% CI; 0.475–0.564, P = 0.0018). GAM analysis revealed a J-shaped relationship for RCII, with optimal thresholds of 2.47 for NIHSS and 0.45 for three-month mRS, indicating significant associations above these cutoffs. The subgroup analysis showed stronger associations for RCII in men, smokers, and individuals with hypertension, but no significant associations were found for RC in any subgroup. The RCII serves as an independent predictor of unfavorable three-month prognoses among individuals diagnosed with AIS. As a composite biomarker combining lipid and inflammatory factors, the RCII can enhance early risk stratification and guide personalized prognostic prediction in Acute stroke management.

Stroke-associated pneumonia (SAP) is a frequent complication of acute ischemic stroke (AIS) that contributes to poor clinical outcomes. The systemic immune-inflammation index (SII), derived from neutrophil, lymphocyte, and platelet counts, may reflect post-stroke immune imbalance, but its role in predicting SAP remains unclear. In this retrospective study, we analyzed 1,767 AIS patients and evaluated the association between log₂-transformed SII and the occurrence of SAP using multivariable logistic regression, generalized additive models, and two-piecewise regression. SAP developed in 21.3% of patients during hospitalization. Higher SII levels were independently associated with increased SAP risk after adjustment for age, sex, vascular risk factors, comorbidities, baseline National Institutes of Health Stroke Scale (NIHSS) score, and dysphagia assessed by Kubota Water Drinking Test (KWDT). Patients in the highest SII quartile had a significantly greater likelihood of developing SAP compared to those in the lowest quartile (adjusted odds ratio = 2.03, 95% confidence interval: 1.21–3.38, p = 0.0069). A non-linear, threshold-dependent relationship was identified, with SAP risk increasing substantially beyond log₂-SII ≈ 8.5. Receiver operating characteristic (ROC) analysis demonstrated moderate predictive performance of SII for SAP (area under the curve (AUC) = 0.726), while C-reactive protein (CRP) showed superior discrimination (AUC = 0.826 p < 0.0001). Supplementary sensitivity analyses, including a fully adjusted model without NIHSS and KWDT and an alternative model replacing these with the A2DS2 score (Age, Atrial fibrillation, Dysphagia, Sex, Stroke Severity), showed consistent results, supporting the robustness of our findings. These findings suggest that SII may serve as a cost-effective and accessible biomarker to aid early identification of high-risk AIS patients.

Acute ischemic stroke (AIS) prognosis is significantly influenced by early neurological deterioration (END). Emerging evidence suggests that thyroid function, particularly free triiodothyronine (FT3) levels and the FT3/FT4 ratio, may play a crucial role in END occurrence. This study aimed to investigate the association between thyroid function parameters and END. This study included a total of 1767 AIS patients. Multivariable regression analysis was conducted to assess the associations between FT3, the FT3/FT4 ratio, and other thyroid function parameters with END. Subgroup analyses were performed to explore the potential moderating effects of age, smoking status, and sex on these relationships. The predictive performance of the models was evaluated using receiver operating characteristic (ROC) curves. The FT3 levels (3.66 vs. 4.03 pmol/L, P < 0.001) and the FT3/FT4 ratio (0.28 vs. 0.30, P < 0.001) were significantly lower in the END group compared to the non-END group. Multivariable regression analysis identified a higher FT3/FT4 ratio as an independent protective factor against END (OR = 1.20, 95 % CI: 1.07-1.35, P = 0.0014). Subgroup analyses demonstrated that this protective effect was more pronounced inpatients older than 70 years, and non-smokers. Furthermore, the predictive model incorporating thyroid function parameters demonstrated certain predictive advantages over the CRP-based model (AUC = 0.688 vs. 0.624, P = 0.0036), suggesting its potential utility in predicting early neurological deterioration in AIS patients. Lower FT3 levels and a reduced FT3/FT4 ratio are significantly associated with a higher risk of END. The FT3/FT4 ratio may serve as a valuable biomarker for risk stratification in AIS patients, underscoring the potential role of thyroid function in stroke management.

Objective To evaluate the association between the stress hyperglycaemia ratio (SHR) and baseline stroke severity in patients with acute ischaemic stroke (AIS) and to investigate whether the relationship is non-linear. Design Retrospective cohort study. Setting A tertiary hospital in Zhejiang Province, China. Participants 1479 consecutive AIS patients admitted within 24 hours of symptom onset between 2016 and 2022. Primary and secondary outcome measures SHR was calculated as fasting plasma glucose (mmol/L) divided by glycated haemoglobin (HbA1c, %). Stroke severity was assessed by the NIH Stroke Scale (NIHSS) and categorised as mild (NIHSS ≤5) or moderate to severe (NIHSS >5). Associations between SHR and stroke severity were examined using multivariable logistic regression, generalised additive models and threshold effect analysis. Results Patients with more severe strokes had significantly higher SHR values (median 0.99 vs 0.94; p<0.001). After full adjustment, higher SHR remained independently associated with increased odds of moderate-to-severe stroke (OR=2.90; 95% CI: 1.60 to 5.26; p=0.0004). SHR in the highest quartile (Q4) was linked to a greater risk compared with the lowest quartile (Q1) (OR=1.90; 95% CI: 1.31 to 2.76; p=0.0008). Non-linear analysis revealed a threshold at SHR=1.3, with sharply increased risk below this point (OR=6.11; 95% CI: 2.64 to 14.15; p<0.0001). Subgroup findings were consistent, with a significant interaction across TOAST subtypes (P for interaction=0.0042). Conclusions SHR is independently associated with greater stroke severity at admission. Values below 1.3 may reflect heightened metabolic stress and could help inform early risk stratification in AIS management, but their discriminative power is limited and should be interpreted in conjunction with other clinical indicators.

Objective: To examine the association between serum 25-hydroxyvitamin D and visceral fat area in adults with type 2 diabetes and assess the exposure–response pattern. Methods: This retrospective cross-sectional study included 1271 adults with type 2 diabetes. Serum 25-hydroxyvitamin D was analyzed as a continuous variable and by quartiles. Multivariable linear regression models were sequentially adjusted for demographic, lifestyle, and metabolic factors, with body mass index added separately in the fully adjusted model. A generalized additive model was used to assess the exposure–response relationship. Prespecified subgroup analyses were also performed. Results: Visceral fat area differed across quartiles of serum 25-hydroxyvitamin D, with a lower median value in Q4 than in Q1 (87.0 vs. 96.0 cm ² ; p = 0.002). Higher serum 25-hydroxyvitamin D was associated with lower visceral fat area in the multivariable model without body mass index (β = −0.77, 95% confidence interval: −1.13 to −0.41; p < 0.0001) and in the body mass index-adjusted model (β = −0.53, 95% confidence interval: −0.80 to −0.27; p < 0.0001). In quartile analyses, participants in Q4 had lower visceral fat area than those in Q1 in the body mass index-adjusted model (β = −10.04, 95% confidence interval: −16.19 to −3.89; p = 0.0015), whereas the associations for Q2 and Q3 were not statistically significant; nevertheless, a significant trend was observed across quartiles (p for trend = 0.0005). The generalized additive model suggested an approximately linear inverse association between serum 25-hydroxyvitamin D and visceral fat area. Conclusions: In adults with type 2 diabetes, higher serum 25-hydroxyvitamin D levels were associated with lower HDS-2000-estimated visceral fat area, although the association was attenuated after adjustment for body mass index. This cross-sectional association should not be interpreted as independent of overall adiposity or unmeasured lifestyle, comorbidity, and treatment-related factors. Longitudinal studies are needed to clarify temporality.

Background: Thyroid hormone sensitivity, reflected by the free triiodothyronine-to-free thyroxine ratio (FT3/FT4), plays a critical role in metabolic regulation. This study aimed to investigate the association between FT3/FT4 and obesity in euthyroid patients with type 2 diabetes. Methods: A total of 1,408 euthyroid patients with type 2 diabetes were included. Multivariable linear regression, subgroup, mediation, and nonlinear analyses were performed to examine the associations between FT3/FT4 and body mass index (BMI). Results: FT3/FT4 was positively and independently associated with BMI in fully adjusted models (β = 7.03, 95% CI: 2.53–11.53, P = 0.0023). Subgroup analyses showed consistent associations across age, sex, and drinking categories, with no significant interactions. Mediation analyses indicated that waist circumference and visceral fat mediated 43.6% and 50.5% of the total effect, respectively, whereas subcutaneous fat was not significant. Nonlinear curve fitting revealed a threshold at FT3/FT4 = 0.41, below which FT3/FT4 was positively associated with BMI, while above it, the association plateaued. Conclusions: FT3/FT4 is independently associated with obesity in euthyroid patients with type 2 diabetes. Its partial mediation through central adiposity and threshold-dependent pattern suggest that FT3/FT4 may serve as a practical biomarker for early risk identification and personalized obesity management. Clinical trial number: not applicable.