Table 2.
Association of Mx and PRx with 3-month outcome in various patient subgroups
| Subgroup specification | Correlations | |||
|---|---|---|---|---|
| Number of patients | Pearson correlation coefficient; AUC of ROC curve; critical threshold | |||
| N; N(mRS) | mRS–Mx | mRS–PRx | Mx–PRx | |
| 41; 36 | 0.48***; 0.80***; 0.20 | 0.38*; 0.64; 0.10 | 0.55*** | |
| Type of disease | ||||
| TBI | 20; 16 | 0.49 | 0.63**; 0.89**; −0.06 | 0.56** |
| Non-TBI | 21; 20 | 0.49*; 0.79*,#; 0.14 | 0.09 | 0.55** |
| Age | ||||
| >60 years | 14; 13 | 0.18 | 0.44 | 0.06 |
| <60 years | 27; 23 | 0.43*; 0.71 | 0.30 | 0.62*** |
| PaCO2 (mmHg) | ||||
| 26–40 | 31; 26 | 0.55***; 0.77*; 0.14, 0.59 | 0.31 | 0.57*** |
| 30–49 | 39; 34 | 0.59***; 0.82***; 0.20 | 0.47**; 0.69 | 0.58*** |
| 35–49 | 27; 24 | 0.68***; 0.92***; 0.00 | 0.57***; 0.76 | 0.68*** |
| Heart failure | ||||
| Yes | 18; 17 | 0.69***; 0.92***; 0.00 | 0.34 | 0.37 |
| No | 23; 19 | 0.38 | 0.43 | 0.63*** |
| Hemicraniectomy | ||||
| Yes | 19; 17 | 0.69***; 0.87*; 0.26 | 0.73***; 0.89**; 0.07 | 0.58** |
| No | 22; 19 | 0.41 | 0.10 | 0.53** |
| Diabetes mellitus II | ||||
| Yes | 15; 15 | 0.20 | 0.41 | 0.57* |
| No | 26; 21 | 0.68***; 0.87***; 0.00 | 0.36 | 0.57*** |
In the complete patient population and in various subgroups correlations were calculated between mRS and Mx and PRx as well as between PRx and Mx. If the index correlated with mRS and number of cases was at least 15, AUC with critical threshold, sensitivity and specificity of index for prediction of poor outcome (mRS ≥ 4) were presented. PRx and Mx mutually correlated except in patients above 60 years and in patients with heart failure. Mx did not correlate with mRS in patients above 60, in patients with diabetes, and in patients without heart failure. PRx correlated with mRS in TBI patients. PRx did not correlate with mRS in non-traumatic patients, in age-specified subgroups, and in the heart failure and diabetes related subgroups. In patients with hemicraniectomy, both PRx and Mx correlated with mRS, but did not in patients without hemicraniectomy. Predictive value of indexes was higher in normal PaCO2 range (>35 mmHg) than in patients with low PaCO2 (26–35 mmHg). Although AUC clearly differed between Mx and PRx, the difference was significant only in the group of non-traumatic patients
AUC area under the curve; correlation: for simplicity denotes a significant correlation, mRS modified Rankin Scale, N population size; N(mRS) number of patients with known 3-month mRS score
Significance levels: * p < 0.05; ** p < 0.01; *** p < 0.005; *** p < 0.001; # significance of Mx–PRx difference in AUC (p < 0.05)