Table 3.

Loading Matrix for Principal Component Analysis (PCA) of 6-month GOS-E, Qualitative CT Predictors, Age, and GCS

	Components
Predictors	1	2	3	4
Age	0.12	0.30	0.15	−0.19
GCS	−0.40	0.16	0.17	0.06
SAH/IPH (present/absent)	0.27	0.40	0.32	0.11
SDH (present/absent)	0.49	0.23	0.14	0.02
EDH (present/absent)	0.02	−0.08	0.13	0.75
Shift >5 mm (present/absent)	0.62	0.12	0.08	0.08
Cistern effacement	0.65	0.09	0.05	−0.02
GOS-E at 6 months	−0.40	0.02	0.06	0.04

Loading matrix for principal component analysis of 6-month GOS-E, qualitative CT predictors, age, and GCS. Numbers represent individual loading coefficients of qualitative CT predictors, age, and GCS upon the first four components. Boxes highlight significant loading coefficients with magnitude ≥0.3. This global PCA analysis, performed on outcome and predictor variables together, demonstrates an interdependence of 6-month GOS-E, GCS, and several qualitative CT predictors related to intracranial mass effect (SDH volume, shift, and cistern effacement). Although similar to results for quantitative CT, the loading coefficients for GOS-E and quantitative CT in Table 1 were larger, suggesting stronger covariances among these factors.

PCA, principal component analysis; GOS-E, Extended Glasgow Outcome Score; GCS, Glasgow Coma Scale; SAH, subarachnoid hemorrhage; IPH, intraparenchymal hemorrhage; SDH, subdural hematoma; EDH, epidural hematoma.