Predictive Value of Fibrin Fibrinogen Degradation Products-to-Potassium Ratio for Poor Functional Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage: A Retrospective Case-Control Study

Abstract

Background: The relationship of fibrin(ogen) degradation products (FDPs) and potassium with the functional outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) is still uncertain. This study aims to evaluate the predictive value of a novel combination biomarker, the FDP-to-potassium ratio (FPR), for poor functional outcomes in patients with aSAH.

Methods: A total of 425 consecutive patients with aSAH at a single center were retrospectively enrolled in our study. An unfavorable outcome was defined as a modified Rankin Scale (mRS) score of 3-6 at 3 months after discharge. Univariate analysis and multivariable logistic regression were performed for baseline information and laboratory parameters recorded at admission. In addition, the receiver operating characteristic curve was plotted, and propensity score matching was performed based on the FPR.

Results: On the basis of mRS grade, 301 patients were classified as having favorable outcomes, and 124 patients were assessed as having unfavorable outcomes. FPR levels were significantly correlated with mRS grade (r[Spearman] = 0.410; P < 0.001). Multivariate logistic regression analysis showed that age (odds ratio [OR] 1.043, 95% confidence interval [CI] 1.016-1.071; P = 0.002), white blood cell count (OR 1.150, 95% CI 1.044-1.267; P = 0.005), potassium (OR 0.526, 95% CI 0.291-0.949; P = 0.033), World Federation of Neurosurgical Societies grade (OR 1.276, 95% CI 1.055-1.544; P = 0.012), and FPR (OR 1.219, 95% CI 1.102-1.349; P < 0.001) at admission were independently associated with poor functional outcomes. The DeLong test showed that the area under the receiver operating characteristic curve of FPR was higher than that of age, white blood cell count, potassium, World Federation of Neurosurgical Societies grade, or FDP alone, indicating that FPR had better predictive potential than these other variables. After 1:1 propensity score matching (FPR ≥ 1.45 vs. FPR < 1.45), the rate of poor prognosis was still significantly increased in the high-FPR group (48/121 [39.7%] vs. 16/121 [13.2%], P < 0.001).

Conclusions: Fibrin(ogen) degradation product-to-potassium ratio is an independent predictor of poor outcomes for patients with aSAH and may be a promising tool for clinicians to evaluate patients' functional prognosis.

Keywords: Aneurysmal subarachnoid hemorrhage; Fibrin fibrinogen degradation products; Hypokalemia; Outcome; Potassium; Predict.

Fig. 1

Flow diagram of patients in the study. A total of 425 patients were included in the final study after excluding 700 patients who did not meet the inclusion criteria. We classified the patients according to their 3-month functional outcomes, (mRS 0–2 vs. 3–6). aSAH, aneurysmal subarachnoid hemorrhage, mRS, modified Rankin Scale

Fig. 2

The correlation of FDP with WFNS grade and modified Fisher score. Scatterplot showing that the FDP increased with WFNS grade (Spearman’s r = 0.325, P < 0.001) and modified Fisher score (Spearman’s r = 0.147, P = 0.002). FDP, fibrin(ogen) degradation product, mFisher, modified Fisher, WFNS, World Federation of Neurosurgical Society

Fig. 3

Comparison of FPR between the favorable outcome and unfavorable outcome groups in mRS grade (mRS 0–2 vs. mRS 3–6). Box plots show the median, upper quartiles, and lower quartiles. FPR, fibrin(ogen) degradation products-to-potassium ratio, mRS, modified Rankin Scale

Fig. 4

The correlation of FDP, potassium, and FPR levels with mRS grade. Scatterplot showing that the FPR increases with mRS grade (Spearman’s r = 0.410, P < 0.001). The same trends held with the FDP (Spearman’s r = 0.403, P < 0.001) and potassium presented a negative correlation trend with increasing mRS grade (Spearman’s r =  − 0.201, P < 0.001). FDP, fibrin(ogen) degradation products, FPR, fibrin(ogen) degradation products-to-potassium ratio, mRS, modified Rankin Scale

Fig. 5

Receiver operating characteristic (ROC) curves for predicting functional outcome at 3 months. Variables include FPR, WFNS grade, age, WBC, potassium, and FDP. Delong tests were performed to compare FPR with other predictors, and results showed the AUC of FPR was significantly higher than that of other predictors. AUC, area under the curve, FDP, fibrin(ogen) degradation products, FPR, fibrin(ogen) degradation products-to-potassium ratio, WBC, white blood cells, WFNS, World Federation of Neurological Society

Fig. 6

The mRS grade at 3 months for patients with aSAH with FPR level differences (FPR ≥ 1.45 vs. FPR < 1.45) after propensity-score matching. Comparisons of functional outcomes and mortality between the two groups were performed by χ² test or Fisher’s exact test. aSAH, aneurysmal subarachnoid hemorrhage, FPR, fibrin(ogen) degradation products-to-potassium ratio, mRS, modified Rankin Scale