BACKGROUND: Cognitive impairment, including dementia, and hip fracture are both common among older patients. Both conditions are associated with increased morbidity and mortality. Cognitive impairment is often underdiagnosed and may remain undetected in hip fracture patients. Little is known about the prevalence, specific characteristics, and outcomes of hip fracture patients with cognitive impairment. This analysis aimed to compare hip fracture patients with and without cognitive impairments regarding their health conditions, hospital care, and the risk of complications and mortality. METHODS: This study used data derived from the EMAAge project, a prospective multi-center cohort study conducted in Berlin, Germany. Patients aged 40 years and older with hip fracture were stratified into three cognitive status groups: no cognitive impairment (NCI), moderate cognitive impairment (MCI), and severe cognitive impairment (SCI). Categorization was based on patients' ability to engage in interviews and their performance on the 6-item Cognitive Impairment Test (6-CIT). Standardized mean differences were used to compare various health-related parameters and health care utilization measures. Regression models, both adjusted and unadjusted, were calculated for the number of complications and the mortality rate. RESULTS: Cognitive impairment was present in 37% of the 310 hip fracture patients in the study cohort. Patients with cognitive impairment had a worse baseline health profile, delayed admission to the emergency department, a longer time to surgery, and were less likely to be referred to a rehabilitation program. In the adjusted regression model for the number of complications, the incidence rate ratio was 1.237 (p = 0.292) for MCI patients and 2.065 (p <
0.001) for SCI patients compared with NCI patients. The adjusted odds ratio for mortality was 1.046 (p = 0.942) for MCI patients and 2.875 (p = 0.060) for SCI patients. CONCLUSIONS: Hip fracture patients with cognitive impairment, particularly severe impairment, arrive at the ED in a considerably poorer state of health and are at a higher risk of adverse outcomes, including complications and mortality. Timely identification of this at-risk group upon arrival appears to be essential to providing adequate care. This study highlights the need for interventions and research aimed at improving prevention, emergency care and outcomes for this vulnerable group, addressing their specific risk factors, and promoting the quality of care in hospital and after discharge.