Surgical site infection after hip fracture – mortality and risk factors: an observational cohort study of 1,709 patients

Christian T Pollmann; Fredrik A Dahl; Jan Harald M Røtterud; Jan-Erik Gjertsen; Asbjørn Årøen

doi:10.1080/17453674.2020.1717841

Authors

Christian T Pollmann Department of Orthopedic Surgery, Akershus University Hospital, Lørenskog; Institute of Clinical Medicine, Campus Ahus, University of Oslo, Oslo
Fredrik A Dahl Institute of Clinical Medicine, Campus Ahus, University of Oslo, Oslo; Health Services Research Unit, Akershus University Hospital, Lørenskog
Jan Harald M Røtterud Department of Orthopedic Surgery, Akershus University Hospital, Lørenskog
Jan-Erik Gjertsen Norwegian Hip Fracture Register, Department of Orthopedic Surgery, Haukeland University Hospital, Bergen; Department of Clinical Medicine (K1), University of Bergen, Bergen
Asbjørn Årøen Department of Orthopedic Surgery, Akershus University Hospital, Lørenskog; Institute of Clinical Medicine, Campus Ahus, University of Oslo, Oslo; Department of Sports Medicine; Norwegian School of Sport Sciences, Oslo, Norway

DOI:

https://doi.org/10.1080/17453674.2020.1717841

Abstract

Background and purpose — Surgical site infection (SSI) is a devastating complication of hip fracture surgery. We studied the contribution of early deep SSI to mortality after hip fracture surgery and the risk factors for deep SSI with emphasis on the duration of surgery.

Patients and methods — 1,709 patients (884 hemiarthroplasties, 825 sliding hip screws), operated from 2012 to 2015 at a single center were included. Data were obtained from the Norwegian Hip Fracture Register, the electronic hospital records, the Norwegian Surveillance System for Antibiotic Use and Hospital-Acquired Infections, and the Central Population Register.

Results — The rate of early (≤ 30 days) deep SSI was 2.2% (38/1,709). Additionally, for hemiarthroplasties 7 delayed (> 30 days, ≤ 1 year) deep SSIs were reported. In patients with early deep SSI 90-day mortality tripled (42% vs. 14%, p < 0.001) and 1-year mortality doubled (55% vs. 24%, p < 0.001). In multivariable analysis, early deep SSI was an independent risk factor for mortality (RR 2.4 for 90-day mortality, 1.8 for 1-year mortality, p < 0.001). In univariable analysis, significant risk factors for early and delayed deep SSI were cognitive impairment, an intraoperative complication, and increasing duration of surgery. However, in the multivariable analysis, duration of surgery was no longer a significant risk factor.

Interpretation — Early deep SSI is an independent risk factor for 90-day and 1-year mortality after hip fracture surgery. After controlling for observed confounding, the association between duration of surgery and early and delayed deep SSI was not statistically significant.