Biochemical markers of inflammation are associated with increased mortality in hip fracture patients: the Bispebjerg Hip Fracture Biobank.

PURPOSE

The purpose of this study was to examine the possible association between mortality following a hip fracture and known biochemical markers of inflammation.

METHODS

The study population was identified using two local databases from Bispebjerg Hospital (Copenhagen, Denmark): the Hip Fracture Database containing all patients admitted to the hospital with a fractured hip from 1996 to 2012 and the Hip Fracture Biobank, containing whole blood, serum and plasma taken in relation to admission on a subgroup of patients from the Hip Fracture Database, consecutively collected over a period of 2.5 years from 2008 to 2011. The following biochemical markers of inflammation were included: C-reactive protein (CRP), the soluble urokinase plasminogen activating receptor (suPAR), ferritin and transferrin. The association between the blood markers and mortality was examined using Cox proportional hazards models. Hazard ratios (HR) were expressed per quartile increase in the biochemical markers.

RESULTS

A total of 698 patients were included, 69 (9.9%) died within 30 days after sustaining a hip fracture. The HR for 30-day mortality was significantly increased with increasing quartiles of suPAR, CRP and ferritin and with decreasing quartiles of transferrin.

CONCLUSION

This study shows that 30-day mortality after a hip fracture is associated with elevated levels of suPAR, CRP and ferritin as well as with lower levels of transferrin. This excess inflammatory response is likely caused by muscle damage associated with the hip fracture. However, this needs to be further clarified.