Comparison of mental-status scales for predicting mortality on the general wards

Altered mental status is a significant predictor of mortality in inpatients. Several scales exist to characterize mental status, including the AVPU (Alert, responds to Voice, responds to Pain, Unresponsive) scale, which is used in many early-warning scores in the general-ward setting. The use of the Glasgow Coma Scale (GCS) and Richmond Agitation Sedation Scale (RASS) is not well established in this population.

To compare the accuracies of AVPU, GCS, and RASS for predicting inpatient mortality.

Retrospective cohort study.

Single, urban, academic medical center.

Adult inpatients on the general wards.

Nurses recorded GCS and RASS on consecutive adult hospitalizations. AVPU was extracted from the eye subscale of the GCS. We compared the accuracies of each scale for predicting in-hospital mortality within 24 hours of a mental-status observation using area under the receiver operating characteristic curves (AUC).

There were 295,974 paired observations of GCS and RASS obtained from 26,873 admissions; 417 (1.6%) resulted in in-hospital death. GCS and RASS more accurately predicted mortality than AVPU (AUC 0.80 and 0.82, respectively, vs 0.73; P < 0.001 for both comparisons). Simultaneous use of GCS and RASS produced an AUC of 0.85 (95% confidence interval: 0.82-0.87, P < 0.001 when compared to all 3 scales).

In ward patients, both GCS and RASS were significantly more accurate predictors of mortality than AVPU. In addition, combining GCS and RASS was more accurate than any scale alone. Routine tracking of GCS and/or RASS on general wards may improve the accuracy of detecting clinical deterioration.