We assessed the relationship of estimated glomerular filtration rate values at hospital admission on the outcome of surgically treated older adults who had suffered a hip fracture. Prospective study that included patients > 65 years of age, surgically treated for primary hip fracture, with no pathologic or high-energy trauma aetiology admitted to a tertiary teaching hospital between 2018 and 2019. We stratified patients based on their estimated glomerular filtration rate at admission and examined its association to demographic and clinical variables, including 90-day post-discharge mortality. The study included 942 hip fracture patients. Lowered estimated glomerular filtration rate was significantly associated to a worsening of the functional status, higher incidence of medical postoperative complications, higher postoperative renal dysfunction, and greater number of blood transfusions. Mortality displayed a staircase pattern, increasing with decreasing estimated glomerular filtration rate. Patients with estimated glomerular filtration rate <60 had significantly higher mortality at 90 days after discharge. In-hospital mortality rate was 10.7% in hip fracture patients with chronic kidney disease who experienced a significant variation in the estimated glomerular filtration rate (>5 mL/min/1.73m2) on admission in comparison to baseline values. Older adult patients treated for hip fracture with lower glomerular filtration rate values have poorer functional status and worse prognosis. A significant clinical variation of estimated glomerular filtration rate upon hospital admission for hip fracture may be associated with increased in-hospital mortality of chronic kidney disease patients.