How long is strict bed rest necessary after renal biopsy?

No consensus exists on the amount of bed rest required after renal biopsy. Moreover, forced prolonged bed rest can be uncomfortable in patients undergoing renal biopsy.

To evaluate whether the length of strict bed rest affects the incidence of pain and other complications after renal biopsy. STUDY DESIGN, FACILITY, AND PATIENTS: This single-center retrospective observational study was conducted in 94 consecutive patients undergoing biopsy of a native kidney between November 2005 and December 2006 at Mie University Hospital. The control group was composed of 317 patients who underwent biopsy of a native kidney between January 2001 and October 2005.

The incidence of biopsy-related complications was compared between two periods of strict bed rest: 2 h of strict bed rest with no abdominal bandage (November 2005 to December 2006) and 7 h of strict bed rest with an abdominal bandage (January 2001 to October 2005). The primary outcome was the incidence of back pain requiring analgesics. The secondary outcomes were: need for transfusion or hemostatic intervention, decrease of >/=10% in hemoglobin (Hb) after biopsy, macroscopic hematuria, infection possibly related to biopsy, need for single or indwelling bladder catheterization, and other biopsy-related complications.

The incidence of back pain requiring analgesics decreased with a shorter period of strict bed rest [7.5% versus 21.1%, odds ratio (OR) 0.30, 95% confidence interval (95% CI) 0.12-0.64, p = 0.004]. Even after adjustment for age, sex, perinephric hematoma size, and number of biopsy punctures, the incidence of back pain decreased significantly (OR 0.34, 95% CI 0.14-0.73, p = 0.01). With a shorter period of strict bed rest, there were no significant differences in bleeding complications (need for transfusion or other hemostatic intervention), decrease of >or=10% in Hb or macroscopic hematuria. However, the need for indwelling bladder catheterization decreased significantly (36.2% versus 50.5%, OR 0.55, 95% CI 0.34-0.88, p = 0.013).

Shortening the period of strict bed rest after renal biopsy from 7 h to 2 h decreased the incidence of back pain, but there was no increase in bleeding or other biopsy-related complications. Our findings suggest that a shorter period of strict bed rest can safely reduce discomfort in renal biopsy patients.