Changes in short-term cognitive function following a hip fracture in the elderly and the effect of cognitive function on early post-operative function

Objective: To evaluate the changes in short-term cognitive function and the relation between cognition and early post-operative functional outcome in the elderly following a hip fracture. Design: Prospective pre-test-post-test observational study.Setting: Two public hospitals in Johannesburg, South Africa.Participants: Ninety elderly patients with a first time unilateral hip fracture over the age of 60 years were consecutively sampled.Patients with polytrauma and those with co-morbidities affecting mobility (stroke, Parkinson's disease or a spinal cord injury) were excluded.Patients re-admitted with complications of a previous surgery or those managed conservatively were also excluded.Seventy-two participants completed the study.Data collection: Pre-operative (baseline), discharge and six weeks post discharge assessments were carried out.Cognitive function was established using the Six-Item Cognitive Impairment Test (6CIT) at each of the three assessment periods.The participants' post-operative functional level was assessed using the Elderly Mobility Scale (EMS) and the Lower Extremity Functional Scale (LEFS) at discharge and at six weeks post discharge.Results: This study revealed significant advances in cognition from baseline to six weeks post discharge (z-statistic -5.04, p=0.000).After adjusting for pre-fracture functional mobility and pre-existing co-morbidities, a multivariate regression analysis revealed that cognitive function is also a strong predictor of early post-operative functional outcome (β= -0.14, p=0.036). Conclusion:Cognitive function in elderly individuals with a hip fracture does improve over time.Cognitive function is a strong predictor of early post-operative functional outcome, when adjusted for pre-fracture functional mobility and pre-existing co-morbidities.