title: Risk factors and timing of native kidney biopsy complications.
abstract: BACKGROUND
  The appropriate observation period, rate and risk factors of complications after a percutaneous renal biopsy remain debated.
  
  
  METHODS
  We retrospectively studied native kidney biopsies performed in our institution between January 2007 and July 2011. Outpatients had either an 8- (67%) or a 24-hour (33%) observation period.
  
  
  RESULTS
  312 biopsies were reviewed (287 patients), 51% of patients were female and the mean age was 54 ± 15 years. Half of these biopsies were performed in outpatients. A total of 15% of patients developed a symptomatic hematoma, 9% received a red blood cell transfusion and 1% required an angio-intervention. Eighty-four percent of the complications manifested within the first 8 h, 86% at 12 h and 94% at 24 h. Outpatients experienced significantly less complications, all manifesting within the first 8 h, 14% required an observation period longer than planned. The risk of symptomatic hematoma increased to 11, 20, 35 and 40% in patients with >200, 140-200, 100-140 and <100 × 10(9)/l platelets, respectively (p = 0.002). It also increased in hemodialysis patients (29% compared to 14%, p = 0.02). We found no association of risk with the number of biopsy passes and only a trend with needle size.
  
  
  CONCLUSIONS
  Symptomatic hematomas occurred in 15% of kidney biopsies and were strongly associated with platelet count and hemodialysis. Outpatients experienced fewer complications; therefore, we can conclude that same-day discharge in selected patients is safe.
authors.affiliation: Division of Nephrology, Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, Que., Canada.
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Simard-Meilleur
authors.affiliation: Division of Nephrology Division, Hôpital du Sacré-Cœur de Montréal, Montreal, Que., Canada.
authors.forename: Stéphan
authors.initials: S
authors.lastname: Troyanov
authors.affiliation: Division of Nephrology, Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, Que., Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Roy
authors.affiliation: Division of Radiology, Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, Que., Canada.
authors.forename: Etienne
authors.initials: E
authors.lastname: Dalaire
authors.affiliation: Division of Nephrology, Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, Que., Canada.
authors.forename: Soumeya
authors.initials: S
authors.lastname: Brachemi
keywords: Hematoma; Kidney biopsy; Risk factors; Timing of complications