Preoperative anemia and postoperative morbidity in patients with hip fracture surgery

Bosch Duran L., Villar Colmenero T., Lamora Tost M., Castelltort Mascó L., Moltó Garcia L., Bisbe Vives E.
Parc de Salut Mar, Dept of Anaesthesiology & Intensive Care, Barcelona, Spain

Background and Goal of Study: 
About 30-40% of the patients with hip fracture have preoperative anemia and 10% severe anemia1. Preoperative anemia is an independent predictor of mortality in surgical patients2. The aim of this study is to determine the relationship between preoperative anemia and postoperative morbidity and which are the risk factors associated to preoperative anemia. 

Materials and methods: 
Institutional protocol for audit the hip fracture surgery procedure, involved in the quality program of our hospital. Were included all patients undergoing hip fracture surgery from June1st to December31th, 2014. We collected demographics data, comorbidity, oral anticoagulants or antiplatelet therapy, complete blood cell count and hematinic levels, delay of surgery, type of anesthesia, type of fracture, transfusion rate, hospital length stay and complications. The preoperative anemia cohort was compared against the cohort without anemia.
A descriptive and bivariate analysis was performed using the Student's T-test for quantitative variables and Pearson's chi-squared test for qualitative variables. A value of p< 0.05 was considered statistically significant.

Results and discussion: 
We included 182 patients. Average age was 84±7 years old, 80% women and 60% ASA III-IV. About 44% of patients had preoperative anemia and 20.7% preoperative iron deficiency. The transfusion rate was 59%. Preoperative anemia was significantly associated with female gender (p=0.001) and low glomerular filtration rate (81% anemic versus 35.6% without anemia; p= 0.001), but not with age or worse ASA. Anemic patients were transfused twice (p=0.001). The delay in surgery was higher in anemic patients (3.8 versus 2.7 days; p=0.001). The hemoglobin levels were lower in preoperative anemic patients (p=0.001). Anemic patients had more cardiac complications (28% versus 15%; p=0.004), but not respiratory, infectious, neurological or renal complications.

Conclusions: 
The prevalence of anemia in this patients is high and conditioned a high transfusion rate. Female gender and preoperative renal failure were predisposing factors but, surprisingly, not age or worse ASA. Anemia resulted in a significant increase of cardiovascular complications. The treatment of anemia could improve perioperative transfusion rate and postoperative morbidity in this type of surgery.

References: 
1. Wiles MD et al. BrJAnaesth.2011;106(4):501-504.
2. Maxwell MJ et al. BrJAnaesth. 2008;101(4):511-517.