title: Excess length of stay attributable to surgical site infection following hip replacement: a nested case-control study.
abstract: OBJECTIVE
  We estimated the impact of hip replacement-associated surgical site infection (SSI) on morbidity and length of stay.
  
  
  METHODS
  This was a pairwise matched (1 : 1) case-control study nested in a cohort. All patients who underwent hip replacement from January 1, 2000, to June 30, 2004, were prospectively enrolled for the nested case-control design analysis and were monitored from the time of surgery until hospital discharge, including any patients readmitted because of infection.
  
  
  RESULTS
  Among the 1,260 hip replacements performed, 28 SSIs were detected, yielding a crude SSI rate of 2.2%. The median excess length of stay attributable to SSI was 32.5 days (P<.001), whereas the median prolonged postoperative stay due to SSI was 31 days (P<.001). Deep-wound SSI was the type that prolonged hospital stay the most (up to 49 days). Of the patients who developed an SSI, 4 required revision surgery, for an SSI-related morbidity rate of 14.3%.
  
  
  CONCLUSIONS
  SSI prolongs hospital stay; however, although hospital stay is a rough indicator of the cost of this complication, to accurately estimate the costs of SSI, we would need to consider individual costs in a linear regression model adjusted for all possible confounding factors.
authors.affiliation: Servicio de Medicina Preventiva, Hospital Ramon y Cajal, Madrid, Spain. vmonge.hrc@salud.madrid.org
authors.forename: Vicente
authors.initials: V
authors.lastname: Monge Jodra
authors.forename: Lourdes
authors.initials: L
authors.lastname: Sainz de Los Terreros Soler
authors.forename: Cristina
authors.initials: C
authors.lastname: Diaz-Agero Perez
authors.forename: Carmen Maria
authors.initials: CM
authors.lastname: Saa Requejo
authors.forename: Nieves
authors.initials: N
authors.lastname: Plana Farras
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000401:mortality; D016022:Case-Control Studies; D003428:Cross Infection / Q000150:complications / Q000191:economics* / Q000401:mortality; D006801:Humans; D007902:Length of Stay / Q000191:economics / Q000706:statistics & numerical data; D013530:Surgical Wound Infection / Q000150:complications / Q000191:economics* / Q000453:epidemiology / Q000209:etiology / Q000401:mortality / Q000517:prevention & control