Introduction: Proximal Femur Fractures (PFFs) are a significant public health issue and occur in the context of global frailty and aging. Recent literature identifies new patient-related prognostic factors that focus on socioeconomic environment, patient well-being, or nutrition status. Specific scores have been developed, but in most cases, they fail to be in line with the comprehensive geriatric assessment, or don't assess the newly identified prognostic factors, contain multitude collinearities, or are too complex to be used in the daily practice. Hypothesis: A comprehensive score with equal representation of the patient's dimensions does at least as good as the Charlson score (CCI), to predict complications and mortality. Objective: To develop a new comprehensive prognostic score, predicting inpatient complications and mortality up to 5-year after PFF. Material and methods: The patients treated surgically for PFF on a native hip, between 2005 and 2017 were selected from a French national database. The variables were the gender, age, the type of treatment (osteosynthesis or arthroplasty), and the CCI. The outcomes were the medical and surgical complications as inpatient and the mortality (up to 5-year). Variables were grouped into dimensions with similar clinical significance, using a Principal Component Analysis, for instance, bed sores and malnutrition. The dimensions were tested for 90-day mortality and complications, in regressions models. Two scores were derived from the coefficients: SCOREpond (strict ponderation), and SCORE (with loose ponderation: 1 point/ risk factors, -1 point/protective factors). Calibration, discrimination (ROC curves with Area Under Curves AUC), and cross-validation were assessed for SCOREpond, SCORE, and CCI. Results: Analyses were performed on 7756 fractures. The factorial analysis identified seven dimensions: age; brain-related conditions (including dementia): 1738/7756; severe chronic conditions (for instance, organ failures) 914/7756; undernutrition:764/7756; environment, including social issues or housing difficulties: 659/7756; associated trauma: 814/7756; and gender. The seven dimensions were selected for the prognostic score named AtoG (ABCDEFG, standing for Age, Brain, Comorbidities, unDernutrition, Environment, other Fractures, Gender). The median survival rate was 50.8 months 95%IC[49-53]. Anaemia and urologic complications were the most prevalent medical complications (1674/7756, 21%, and 1109/7756, 14.2%). A total of 149/7756 patients (1.9%) developed a mechanical inpatient complication (fractures or dislocations), with a slightly higher risk for arthroplasties. The AUCs were 0.69, 0.68, and 0.67 for AtoGpond, AtoG, and CCI, respectively, for 90-day mortality, and 0.64, 0.63, and 0.56 for complications. Compared to patients with AtoG=0, Hazard Ratios for 90-day mortality were 2.3 95%CI[1.7-2.9], 4.2 95%CI[3.1-5.4], 6 95%CI[4.5-8.1], 8.3 95%CI[6.5-12.9], and 13.7 95%CI[8-24], from AtoG=1 to AtoG>=5, respectively (p <10-4); the 90-day survival decreased by 5%/point, roughly. The sur-risk of mortality associated with AtoG was up to 5-year: HR= 1.51 (95%CI[1.46-1.55], p<10-4). Compared to AtoG=0, from AtoG=1 to AtoG ≥5, the pooled Odd Ratios were 1.14 95%CI[1.06-1.2], 1.53 95%CI[1.4-1.7], 2.17 95%CI[1.9-2.4], 2.9 95%CI[2.4-3.4], and 4.9 95%CI[3.3-7.4] for any complication (p <10-4). Conclusion: AtoG is a multidimensional score in line with the concept of comprehensive geriatric assessment. It had good discrimination and performance in predicting 90-day mortality and complications. Performances were as good as CCI for 90-day mortality, and better than it for the complications. Level of proof: IV; retrospective cohort study.