Trauma-related acute kidney injury during inpatient care of femoral fractures increases the risk of mortality: A claims data analysis

Objectives: Although femoral fractures can hit anyone, they carry an especially high burden in the elderly and are multifaceted in their injury pattern, related complications, and subsequent therapeutic strategies. An often underestimated posttraumatic risk is the development of trauma-related acute kidney injury (TRAKI). However, for TRAKI, no outcome study with a large data approach exists addressing fractures. Therefore, we analyzed the development of TRAKI in regard to different covariates and quantified the association of TRAKI with overall mortality.

Design: Retrospective cohort study with claims data.

Setting and participants: 119,000 patients from Germany with femur fracture.

Methods: We calculated cumulative mortality, mortality rates per 100 person-years (both occurring within 180 days after fracture), and adjusted hazard ratios with 95%-confidence intervals (CI).

Results: Patients with femur shaft fractures showed an incidence of 6.1% for TRAKI, followed by patients with femur neck fractures with an incidence of 5.7%, and by patients with distal fractures with an incidence of 4.5%, respectively. Overall, in patients with any femur fracture, we found a 3.17-times higher mortality rate (95%-CI: 3.02-3.26) during 180 days of observation in patients who developed TRAKI in comparison to patients without. The risk for development of TRAKI was significantly increased with increasing TRAKI stage, age, and time until surgical intervention.

Conclusions and implications: In conclusion, patients suffering from proximal-, shaft-, and distal femoral fracture face an over 3-times higher 180 day-mortality rate in case of posttraumatic TRAKI, which should be considered in peri-traumatic care to improve the long-term outcome of these patients.