The joint effects of inflammation and renal function status on in-hospital outcomes in patients with acute ischemic stroke treated with intravenous thrombolysis

Objective We aimed to determine the predictive value of renal function status [estimating glomerular filtration rate (eGFR)] in conjunction with inflammatory biomarkers [white blood cell(WBC) and C-reactive protein (CRP)] for in-hospital outcomes in acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT). Methods We retrospectively screened a total of 409 AIS patients treated with IVT. The study participants were classified into two groups according to post-stroke pneumonia or functional outcome. They were divided into four groups according to the cut-offs of inflammatory biomarkers and eGFR by receiver operating characteristics(ROC) curves for two outcomes of post-stroke pneumonia and functional status: WBC down arrow/eGFR up arrow, WBC down arrow/eGFR down arrow, WBC up arrow/eGFR up arrow, and WBC up arrow/eGFR down arrow for post-stroke pneumonia; and CRP down arrow/eGFR up arrow, CRP down arrow/eGFR down arrow, CRP up arrow/eGFR up arrow, and CRP up arrow/eGFR down arrow for functional outcome. Logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of post-stroke pneumonia or at-discharge functional outcome, using the WBC down arrow/eGFR up arrow group or CRP down arrow/eGFR up arrow group as the reference. The Net Reclassification Index (NRI) and the Integrated Discrimination Improvement (IDI) were calculated to analyze the combined predictive value. Results Compared with patients in WBC down arrow/eGFR up arrow group, those in WBC up arrow/eGFR up arrow group had increased risk of post-stroke pneumonia (OR 5.15, 95% CI 1.67-15.87) and poor functional outcome (OR 5.95, 95% CI 2.25-15.74). Furthermore, patients in WBC up arrow/ eGFR down arrow group had the highest risk of clinical outcomes (all P value for trend < 0.001), the multivariable-adjusted ORs (95% CIs) were 7.04 (2.42-20.46) for post-stroke pneumonia and 8.64 (3.30-22.65) for poor functional outcome. The addition of WBC and eGFR to the basic model significantly improved risk prediction for post-stroke pneumonia (category-free NRI 69.0%, 95% CI 47.3%-90.7%; IDI 5.4%, 95% CI 2.6%-8.3%) and functional outcome (category-free NRI 59.4%, 95% CI 39.2%-79.9%; IDI 5.3%, 95% CI 2.9%-7.8%). Similarly, when we added CRP and eGFR to the basic model with conventional risk factors, the risk discrimination and prediction for post-stroke pneumonia and functional outcome was also significantly improved. Conclusion Combining renal function status and inflammatory biomarkers within 4.5 h after onset could better predict in-hospital outcomes of AIS patients with IVT.