Abstract
Introduction
The National Hip Fracture Database (NHFD) is the mandatory national clinical audit for patients presenting with hip fracture. Since 2007, the NHFD has made admission cognitive assessment using the Abbreviated Mental Test Score (AMTS) routine for people presenting with this injury. In 2024, the NHFD plans to replace the AMTS with the 4A test (4AT), so all patients are additionally assessed for delirium on presentation. This study aims to compare the AMTS and 4AT for this patient group, so the NHFD and our local team can anticipate the consequences of this change in patient assessment.
Methods
The clerking house officer completed both AMTS and 4AT for patients admitted consecutively under the ‘femur fracture pathway’ to University Hospital Wales between August-October 2023. We classified an AMTS < 8 and 4AT = 1-3 as suggestive of cognitive impairment. A 4AT ≥ 4 also indicated possible delirium.
Results
A total of 100 patients were included, 65 female and 35 male. 4AT was normal (0) in 67/75 patients with normal AMTS (8+). 4AT was abnormal (1+) in 24/25 patients with abnormal AMTS (<8). Screening with 4AT highlighted possible delirium in 15 patients (15%) which may not have been identified by AMTS. Four questions from AMTS form the ‘AMT-4’ sub-domain of 4AT. AMT-4 was normal (0) in 73/75 patients with a normal AMTS, and abnormal (1+) in 22/25 patients with an abnormal AMTS (sensitivity 0.88, specificity 0.97).
Conclusion
The 4AT provides invaluable training in delirium recognition for junior doctors, and highlights aspects of cognition (such as delirium) missed by the AMTS whilst being a quick, user-friendly tool. The AMT-4 subdomain of 4AT proved remarkably consistent with full AMTS results. Our findings are being integrated into local clerking protocols and used by the NHFD in its redesign of cognitive screening nationally.