Validation of orthopaedic surgeons’ assessment of cognitive function in patients with acute hip fracture

BACKGROUND: About one fourth of patients with hip fracture have cognitive impairment. These patients are at higher risk of surgical and medical complications and are often excluded from participating in clinical research. The aim of the present study was to investigate orthopaedic surgeons' ability to determine the cognitive status of patients with acute hip fracture and to compare the treatment given to patients with and without cognitive impairment. METHODS: The cognitive function of 1474 hip fracture patients reported by the orthopaedic surgeons to the nationwide Norwegian Hip Fracture Register was compared with data registered in quality databases in two hospitals with orthogeriatric service on the same patients. Cognitive function registered in the quality databases was determined either by the short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) or by pre-fracture diagnosis of dementia. The information registered in the quality databases was defined as the reference standard. Cognitive function in the Norwegian Hip Fracture Register was reported as: Chronic cognitive impairment? "Yes", "Uncertain" or "No" by the orthopaedic surgeons. Sensitivity, specificity, negative and positive predictive values for chronic cognitive impairment reported to the Norwegian Hip Fracture Register by the orthopaedic surgeons was calculated. Baseline data and treatment of hip fractures in patients with and without cognitive impairment in the Norwegian Hip Fracture Register were compared. RESULTS: Orthopaedic surgeons reported chronic cognitive impairment in 31% of the patients. Using documented dementia or IQCODE > 4.0 as the reference, this assessment of cognitive impairment by the orthopaedic surgeons had a sensitivity of 69%, a specificity of 90%, a positive predictive value of 78%, and a negative predictive value of 84% compared to information registered in the two hospital quality databases. There were no differences in type of hip fracture or type of surgical treatment by cognitive function. CONCLUSION: The treatment of hip fractures was similar in patients with chronic cognitive impairment and cognitively well-functioning patients. The surgeons had an acceptable ability to identify and report chronic cognitive impairment in the peri-operative period, indicating that the Norwegian Hip Fracture Register is a valuable resource for future registry-based research also on hip fracture patients with chronic cognitive impairment.