title: Variability of platelet aggregation in patients with clopidogrel treatment and hip fracture: A retrospective case-control study on 112 patients.
abstract: OBJECTIVE
  To identify the rate of non-responders to clopidogrel treatment in hip fracture patients and study how non-responders differ from controls.
  
  
  METHODS
  In a retrospective case-control study we included 28 cases of acute proximal femoral fracture with clopidogrel treatment 2011 to 2013. Eighty-four controls from the same time period were included. Data collected included response to clopidogrel measured with multiple electrode aggregometry (MEA), intraoperative bleeding, erythrocyte transfusion, time to surgery and the incidence of adverse events up to 3 mo after surgery.
  
  
  RESULTS
  Eight (29%) of the 28 cases were non-responders. The median intraoperative bleeding was 300 mL (range, 0-1500), and was lower for non-responders (50 mL) but did not reach statistical significance. Erythrocyte transfusions did not differ between responders, non-responders and controls. Forty-five (40%) of 112 patients had adverse events postoperatively but the rate did not differ between patients with and without clopidogrel treatment.
  
  
  CONCLUSIONS
  Almost one-third of patients with clopidogrel treatment and an acute proximal femoral fracture are non-responders to antiplatelet therapy and can be operated without delay.
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Anna
authors.initials: A
authors.lastname: Clareus
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Inga
authors.initials: I
authors.lastname: Fredriksson
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Håkan
authors.initials: H
authors.lastname: Wallén
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Max
authors.initials: M
authors.lastname: Gordon
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: André
authors.initials: A
authors.lastname: Stark
authors.affiliation: Anna Clareus, Max Gordon, André Stark, Olof Sköldenberg, Division of Orthopaedics, Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, 18288 Stockholm, Sweden.
authors.forename: Olof
authors.initials: O
authors.lastname: Sköldenberg
keywords: Adverse events; Bleeding; Clopidogrel; Proximal femoral fracture; Variability