Patient deterioration in regional and rural hospitals: Is the Queensland adult deterioration detection system (Q-ADDS) the gold standard

Objective: This study compares the efficiency of six early warning systems (EWSs) to determine whether the EWS used in most public hospitals in Queensland, Australia, Q-ADDS, is best suited for use in small regional and rural hospitals. Method: In this retrospective case-control study, patients who experienced an in-hospital severe-adverse-event (index patients) over a 3.5 year period were demographically and diagnostically matched with patients who had uneventful hospital stays (control patients). The EWS efficiency was based on the Area Under the Receiver Operator Characteristic Curve (AUROC) and the number of false and true alerts generated by each EWS. Result: The incidence of severe-adverse-events was 1.2% of in-hospital patients, 2500 sets of vital signs were collected from 159 index and 172 control patients. The EWSs were only able to identify approximately half of the index patients. The AUROC was 0.666-0.801 and the EWS generated 2.4-7.6 false alerts to every true alert per 1000 admissions. The NEWS had the best ratio of false to true alerts (2.4:1) but was only able to identify 40.8% of deteriorating patients. Q-ADDS identified 46.5% of the deteriorating patients and had a false to true alert ratio of 3.2:1. When compared to the NEWS, systems with higher AUROCs (0.744 and 0.801) also had higher proportion of false alerts. None of the alternative EWSs appear to provide marked benefits over Q-ADDS. Conclusion: At present, there is insufficient evidence to replace Q-ADDS with an alternative EWS. Since the EWSs were only able to identify half of the deteriorating patients, EWSs should be used in conjunction with good clinical judgement.