Purpose <p>Hip fractures are a major health issue among the elderly population and are associated with increased mortality. Chronic comorbidities may cause increased mortality risk among these patients. In this study we examined the impact of chronic comorbidities on 30-day mortality among Danish hip fracture patients along with other risk factors such as sex and fracture type.</p> Patients and methods <p>This study used data from the Danish National Patient Registry. We included patients aged ≥ 70 years who sustained a hip fracture between January 1, 1999, and December 31, 2012. Chronic comorbidities– dementia, heart failure, chronic obstructive pulmonary disease, asthma, ischemic heart disease, diabetes mellitus with complications, chronic kidney disease, and cancer– as well as fracture type were identified using ICD-10 codes.</p> Results <p>A total of 98,850 hip fracture patients were included, of whom 11.5% had died within 30 days. Male patients had a significantly higher 30-day mortality rate (17.7%) than female patients (9.2%). Patients with multiple chronic comorbidities had an increased mortality risk, with patients having ≥ 5 chronic comorbidities exhibiting a 30-day mortality rate of 28.3% compared to 7.8% for patients without any chronic comorbidities. Regarding fracture types, patients with subtrochanteric fractures had a mortality risk of 13.2% compared to patients with a femoral head/neck fracture, who had a mortality risk of 10.8%. In adjusted analyses chronic kidney disease and male sex had the highest association with increased 30-day mortality risk.</p> Conclusion <p>This study shows the significant impact of chronic comorbidities as well as sex and fracture type on 30-day mortality in hip fracture patients. Patients with multiple chronic comorbidities had the highest risk of increased 30-day mortality. These findings underline the importance of interventions such as orthogeriatric care to lower 30-day mortality risk for these patients.</p>