title: Pre-hospital medications in total hip arthroplasty: risk factors for poor outcomes.
abstract: BACKGROUND
  The influence of co-morbidities on complication rates and length of hospitalisation after surgery is well recognised. Clinical instruments predicting this influence, are of increasing interest. We sought to determine whether a count of a patient's preoperative pharmaceuticals would be associated to postoperative outcomes.
  
  
  METHODS
  In this retrospective, consecutive case series, 668 patients undergoing elective primary total hip arthroplasty (THA) were analysed. Age, gender, BMI, ASA-classification, nicotine or alcohol abuse, and the number and type of medications were documented.
  
  
  RESULTS
  Mean age was 63 years (18-94), 53% were females. A total of 60 (8.9%) local and 19 (2.8%) systemic complications occurred during hospital stay. A total of 11 (1.6%) patients died, while 49 (7.3%) local complications occurred during the first postoperative year. Length of hospital stay, blood transfusions, and morbidity were found to be significantly related to the quantity of medications (p&lt;0.001). While the risk of an extended hospital stay (&gt;7 days) increased by a factor of 1.15 (CI: 1.08-1.22) with each medication, the risk of experiencing a complication within the first postoperative year was 1.19 times (CI: 1.07-1.29) for each additional medication. Type of medication also influenced morbidity: the odds ratio was 1.89 (CI: 1.05-3.41) for platelet inhibiting agents and 4.07 (CI: 1.96-8.42) for oral anticoagulants in early morbidity, which increased to 6.05 (CI:2.92-12.53) in 1-year follow-up.
  
  
  CONCLUSIONS
  The investigation illustrated the significant influence of the number and/or type of medication on complications, morbidity and prolonged hospital stay. This predictive tool may be useful, for physicians and non-health professionals, in estimating particular outcomes after elective THA.
authors.affiliation: 1 Department of Orthopaedics, University Hospital Balgrist, Zurich - Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Dietrich
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Zingg
authors.forename: Marco
authors.initials: M
authors.lastname: Egbring
authors.forename: Atul F
authors.initials: AF
authors.lastname: Kamath
authors.forename: Claudio
authors.initials: C
authors.lastname: Dora
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D011183:Postoperative Complications / Q000517:prevention & control*; D011300:Preoperative Care / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D013997:Time Factors; D055815:Young Adult