Should asymptomatic bacteriuria be systematically treated in kidney transplant recipients? Results from a randomized controlled trial.
Origuen J, Lopez-Medrano F, et al.American Journal of Transplantation 2016 [record in progress].
Aims
To determine the effect of antimicrobial treatment of posttransplant asymptomatic bacteriuria (AB) on kidney transplant recipients.
Interventions
Participants were randomized to receive either systematic antimicrobial therapy for AB (treatment group), or no antimicrobial treatment (control group).
Participants
112 adult kidney transplant recipients aged ≥18 years who developed at least one episode of asymptomatic bacteriuria (AB) beyond the second month after transplantation.
Outcomes
The primary outcome measured was the incidence of acute pyelonephritis. Secondary outcomes measured included long-term graft function, all-cause mortality, lower urinary tract infection, acute graft rejection, graft loss, clostridium difficile infection, and colonization or infection due to multidrug-resistant bacteria.
Follow-up
24 months
CET Conclusions
This is a well conducted study and a well written report. However it must be read in the light of two main criticisms, which the authors themselves acknowledge: that it was small due to an incorrect assumption in the power calculation and that there was poor protocol compliance. Overall it suggests that asymptomatic bacteriuria in renal transplant patients should probably not be treated, although there are some caveats that provide more interest. The study showed that 39% of the included patients developed at least one episode of asymptomatic bacteriuria, and patients had, on average 18 urine culture specimens ordered during follow up. The study was designed with the rate of pyelonephritis as the primary outcome. The assumed rate of 23% (of all those with asymptomatic bacteriuria) was far too high and under study conditions the rate was only 8.4% in the control arm (versus 7.5% in the treatment arm). Of note a third of the episodes of pyelonephritis were not preceded by asymptomatic bacteriuria. The adherence was low, particularly in the treatment arm, where only 49% of asymptomatic bacteriuria episodes were treated, and 85% of patients in the control arm went untreated for all episodes. Interestingly 33% of the asymptomatic bacteriuria episodes that were untreated spontaneously cleared. Klebsiella pneumoniae showed low rates of clearances whether treatment was given or not (42% versus 24%). Patients were excluded if a ureteric stent was still in situ. No attempt was made to blind the study and although this may have proved difficult, it would not have been impossible. Another potential criticism is that there is no description of the scheduling of urine cultures. All in all the study struggled with the feasibility of the tested strategy but does provide some support for not treating all episodes of asymptomatic bacteriuria after kidney transplantation and once stents are removed.
Data analysis
Per protocol analysis
Trial registration
ClinicalTrials.gov - NCT02373085