1. Demographic data of patients who experienced SICH
Requisite data from 105 patients who experienced SICH (mean age, 68 years; 75 male) were included for analysis in the present study; the hemorrhage volume in 24 patients was > 30 ml. Among the 105 patients, the baseline hematoma was located in the following regions: basal ganglion (28.6%), lobes (46.7%), epencephalon (9.5%), brainstem (6.7%), and arachnoid cavity (8.5%). In addition, 95 patients who experienced non-cerebral hemorrhage (mean age, 72 years; 69 male) were enrolled as the control group. Correlation analysis revealed that the occurrence of SICH was associated with hypertension, diabetes, and renal dysfunction (P < 0.05). The characteristics of all patients are summarized in Table 1.
2. Abnormal serum calcium and uric acid levels in patients who experienced SICH
In present study, data regarding 8 admission biochemical or blood coagulation parameters, including C-reactive protein (CRP), uric acid, carbamide, creatinine, calcium, activated partial thromboplastin and thrombin time (aPTT), thrombin time (TT), and prothrombin time (PT), were collected (Table 1). When compared with cases of non-cerebral hemorrhage, those who experienced SICH exhibited higher serum uric acid levels (Fig. 1b), while the results for serum calcium were the opposite, with a lower level in the SICH group (Fig. 1f). There were no other differences between the two groups (all P > 0.05) (Table 1, Fig. 1).
3. Serum uric acid and calcium levels predicted hematoma volume in patients who experienced SICH
A positive correlation was found between serum uric acid level and hematoma volume (r2 = 0.167, P < 0.001; Fig. 2a), while uric acid was negatively correlated with hematoma volume (r2 = 0.059, P = 0.013; Fig. 2b). Subsequently, the patients were divided into two groups using the upper limit of serum uric acid or lower limit of serum calcium level as the cut-off value. Results of analysis revealed that hematoma volume in the hyperuricemia group was larger than in the non-hyperuricemia group (Fig. 2c). In contrast, hematoma volume in patients with hypocalcemia was greater than that of non-hypocalcemia patients (Fig. 2d).
4. The value of combining serum calcium and uric acid levels in predicting hematoma volume
The association between serum calcium and uric acid levels was investigated and no correlation was found (Fig. 3a). Based on this, we speculated whether combining the two parameters would be a better predictor of hematoma volume. Accordingly, the patients were divided into three groups: hyperuricemia and hypocalcemia (Group 1); hyperuricemia/non-hypocalcemia or non-hyperuricemia/hypocalcemia (Group 2); and non-hyperuricemia and non-hypocalcemia (Group 3). Analysis revealed that patients in Group 1 exhibited the largest hematoma volume, while those in group 3 exhibited the smallest (Fig. 3b). These findings suggested that the combination of serum calcium and uric acid may have more utility in predicting the volume of intracerebral hemorrhage.