Systematic Review and Meta-analysis of Asymptomatic Bacteriuria After Renal Transplantation: Incidence, Risk of Complications, and Treatment Outcomes

Background: Routine treatment for asymptomatic bacteriuria (ASB) after renal transplantation (RT) represents nowadays a controversial topic, being unknown its impact on the overall prognosis of the transplanted patient.

Methods: Studies published during 1970-2019 that evaluated the benefit of treating ASB after RT regarding the risk of renal complications were included. The primary outcome was to assess whether the treatment is associated with a lower risk of symptomatic urinary tract infection (UTI) or an improved renal function at the end of the follow-up period. The secondary outcome was the risk of acute graft rejection (AGR). A meta-analysis with a random-effect model was performed. Heterogeneity was assessed with the I measure.

Results: Fifteen studies were included. The incidence of ASB in the first month and the first year after RT was 22% and 30%, respectively. ASB was not correlated to AGR (OR 1.18; 95% CI, 0.78-1.79). Eight studies compared the outcomes of ASB treatment, finding no benefit of treating regarding the risk of symptomatic UTI (OR 1.08; 95% CI, 0.63-1.84; I  = 35%) or the change in renal function (mean difference in serum creatinine concentration-0.03 mg/dL,95% CI-0.15-0.10; I  = 53%).

Conclusions: Asymptomatic bacteriuria represents a frequent finding after RT, highlighting the need for appropriate management of this condition. Considering that its treatment did not decrease the risk of the studied complications, antibiotic therapy should start to be questioned, as it has been related to higher rates of antimicrobial resistance and high economic costs.