Emily R Thompson, Sarah A Hosgood, Michael L Nicholson, Colin H Wilson

Kidney transplantation is the treatment of choice for patients with end-stage kidney disease. In a previous review we concluded that the routine use of ureteric stents in kidney transplantation reduces the incidence of major urological complications (MUC). Unfortunately, this reduction appears to lead to a concomitant rise in urinary tract infections (UTI). For kidney recipients UTI is now the commonest post-transplant complication. This represents a considerable risk to the immunosuppressed transplant recipient, particularly in the era of increased immunologically challenging transplants. There are a number of different approaches taken when considering ureteric stenting and these are associated with differing degrees of morbidity and hospital cost. This review aimed to look at the benefits and harms of early versus late removal of the ureteric stent in kidney transplant recipients. We searched the Cochrane Kidney and Transplant Specialised Register up to 27 March 2017 through contact with the Information Specialist using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE, and EMBASE; handsearching conference proceedings; and searching the International Clinical Trials Register Search Portal and ClinicalTrials.gov. All RCTs and quasi-RCTs were included in our meta-analysis. We included recipients of kidney transplants regardless of demography (adults or children) or the type of stent used. Two authors reviewed the identified studies to ascertain if they met inclusion criteria. We designated removal of a ureteric stent before the third postoperative week (< day 15) or during the index transplant admission as "early" removal. The studies were assessed for quality using the risk of bias tool. The primary outcome of interest was the incidence of MUC. Further outcomes of interest were the incidence of UTI, idiosyncratic stent-related complications, hospital-related costs and adverse events. A subgroup analysis was performed examining the difference in complications reported depending on the type of ureteric stent used; bladder indwelling (BI) versus per-urethral (PU). Statistical analyses were performed using the random effects model and results expressed as relative risk (RR) with 95% confidence intervals (CI). Five studies (1127 patients) were included in our analysis. Generally the risk of bias of the included studies was judged low or unclear; they addressed the research question and utilised a prospective randomised design. It is uncertain whether early stent removal verus late stent removal improved the incidence of MUC (5 studies, 1127 participants: RR 1.87, 95% CI 0.61 to 5.71; I2 = 21%; low certainty evidence). The incidence of UTI may be reduced in the early stent removal group (5 studies, 1127 participants: RR 0.49 95% CI 0.30 to 0.81; I2 = 59%; moderate certainty evidence). This possible reduction in the UTI incidence was only apparent if a BI stent was used, (3 studies, 539 participants, RR 0.45 95% CI 0.29 to 0.70; I2 = 13%; moderate certainty evidence). However, if an externalised PU stent was used there was no discernible difference in UTI incidence between the early and late group (2 studies, 588 participants: RR 0.60 95% CI 0.17, 2.03; I2 = 83%; low certainty evidence). Data on health economics and quality of life outcomes were lacking. Early removal of ureteric stents following kidney transplantation may reduce the incidence of UTI while it uncertain if there is a higher risk of MUC. BI stents are the optimum method for achieving this benefit.