Cristina Bermejo Boixareu,1,* Cristina Ojeda-Thies,2,* Ainhoa Guijarro Valtueña,3 Bernardo Abel Cedeño Veloz,4 María Gonzalo Lázaro,4 Laura Navarro Castellanos,5 Rocío Queipo Matas,5,6 Paloma Gómez Campelo,5 Ana Royuela Vicente,7 Juan Ignacio González-Montalvo,5,8 Pilar Sáez-López5,9,10 1Geriatrics Department, Puerta de Hierro Majadahonda University Hospital, Madrid, Spain; 2Orthopaedic Surgery and Traumatology Department, 12 de Octubre University Hospital, Madrid, Spain; 3Orthopaedic Surgery and Traumatology, Puerta de Hierro Majadahonda University Hospital, Madrid, Spain; 4Geriatrics Department, University Hospital of Navarra, Pamplona, Spain; 5La Paz Institute for Health Research - IdiPAZ, Hospital Universitario La Paz - Universidad Autónoma de Madrid, Madrid, Spain; 6European University of Madrid, Madrid, Spain; 7Biostatistics Unit, Puerta de Hierro Majadahonda University Hospital, IDIPHISA, CIBERESP, Madrid, Spain; 8Geriatrics Department, La Paz University Hospital, Madrid, Spain; 9Geriatrics Department, Fundación Alcorcón University Hospital, Madrid, Spain; 10Spanish National Hip Fracture Registry, Madrid, Spain*These authors contributed equally to this workCorrespondence: Cristina Bermejo Boixareu, Geriatrics Department, Puerta de Hierro University Hospital, Madrid, Spain, Email cristina_bermejo@hotmail.comObjective: The primary objective was to describe the clinical characteristics, management, and outcomes of centenarians with fragility hip fracture and compare them to other age groups. The secondary objective was to determine the variables associated with length of stay, in-hospital mortality and 30-day mortality.Materials and Methods: This is a secondary analysis of the Spanish National Hip Fracture Registry. We included patients ≥ 75 years admitted for fragility hip fractures in 86 Spanish hospitals between 2017 and 2019, dividing the sample into four age groups. The variables studied were baseline characteristics, type of fracture, management, length of stay, in-hospital mortality and 30-day mortality.Results: We included 25,938 patients (2888 were 75– 79 years old; 14,762 octogenarians; 8,035 nonagenarians and 253 centenarians). Of the centenarians, 83% were women, 33% had severe dementia, 9% had severe dependency and 36% lived in residential care homes. Six out of ten had intertrochanteric fracture. Length of hospital stay was 8.6 days; in-hospital mortality was 10.3% and 30-day mortality 20.9%. Older age groups had more women, severe functional dependency, severe dementia, intertrochanteric fracture, living in care facilities and being discharged to nursing care. They had less frequent early mobilization, osteoporosis treatment and discharge to rehabilitation units. In-hospital and 30-day mortality were higher with increasing age. In centenarians, time to surgery > 48 hours was independently associated with length of stay (correlation coefficient 3.99 [95% CI: 2.35– 5.64; p< 0.001]) and anaesthetic risk, based on an ASA score of V, was related to 30-day mortality (ASA score II [OR 0.25, 95% CI: 0.09– 0.70; p=0.009] and ASA score III [OR 0.43, 95% CI: 0.19– 0.96; p=0.039]).Conclusion: Centenarians had different clinical characteristics, management and outcomes. Although centenarians had worse outcomes, nearly 4 out of 5 centenarians were alive one month after surgery.Keywords: centenarians, fracture, registry, mortality, ASA grade