title: Intrabiliary rupture of hepatic echinococcosis, a risk factor for developing postoperative morbidity: a cohort study.
abstract: BACKGROUND
  The aim of this study was to determine if intrabiliary rupture (IBR), an evolutive complication of hepatic echinococcosis (HE), is a risk factor for developing postoperative morbidity (POM).
  
  
  METHODS
  This was a concurrent cohort study that included patients operated on for HE between 1996 and 2006 and who had clinical check-ups at 1, 6, 12, 24, 36, 48, and 60 months postoperatively. Principal outcome variable was "development POM," considered dichotomously. The exposure variable was the presence of IBR, analyzed dichotomously (present or absent) and according to the number of IBR (without, with one, and with two or more). The sample size was considered on the basis of a 95% confidence interval (95% CI), a power of 80%, a 1:2 ratio of patients without and with IBR, and a 10% proportion of POM in patients without IBR and 26% in patients with IBR. Descriptive statistics and bivariate and multivariate analyses were used. Relative risks (RR) and 95% CI were calculated.
  
  
  RESULTS
  The cohorts (median age of 42 years, 56.4% female, a median cyst diameter of 15 cm, and a follow-up of 118 months) were composed of 96 patients without IBR (38.1%) and 156 patients with IBR (61.9%). A morbidity rate of 17.1% was verified (9.4% in the group without IBR and 21.8% in the group with IBR [p = 0.011]). An adjusted RR of 3.4 (95% CI = 2.64, 4.18) was verified for the comparison of subgroups without IBR vs. with two or more IBR (p < 0.001).
  
  
  CONCLUSIONS
  The presence of two or more IBR constitutes a risk factor for developing POM in patients with HE.
authors.affiliation: Department of Surgery, Universidad de La Frontera, M. Montt 112, Office 408, Temuco, Chile. cmantero@ufro.cl
authors.forename: Carlos
authors.initials: C
authors.lastname: Manterola
authors.forename: Manuel
authors.initials: M
authors.lastname: Vial
authors.forename: Antonio
authors.initials: A
authors.lastname: Sanhueza
authors.forename: Juan
authors.initials: J
authors.lastname: Contreras
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004444:Echinococcosis, Hepatic / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D012307:Risk Factors; D012422:Rupture, Spontaneous / Q000150:complications; D055815:Young Adult