MO922CASUAL FACTORS AND CLINICAL IMPACT OF URINARY TRACT INFECTIONS IN RENAL TRANSPLANTED PATIENTS: AN OBSERVATIONAL RETROSPECTIVE STUDY*
Authors: Tripodi Federica , Alfieri Carlo Maria , Tangredi Marianna , Cresseri Donata , Campise Maria Rosaria , Gandolfo Maria Teresa , Regalia Anna , Favi Evaldo , Messa Piergiorgio 
Published: May 2021

Abstract

Background and Aims
Urinary tract infections (UTIs) are the most common infectious disease in kidney transplanted patients (KTxps), especially during the first year of kidney transplantation (KTx). This study aims to examine the etiology of UTIs in a large cohort of KTxps, trying to identify their potential predisposing factors both during the first year and in the global follow-up (FU) of KTx. The impact of UTIs on KTx and patient’s survival in the long term will also be analyzed.

Method
In our study 585 KTxps (M 343; median age 49 years), out of the 616 KTxps transplanted in our Department between 2004 and 2016, were studied and followed up for a median time of 8 years. Clinical and biochemical data about the 1st (T1) and the 12th month (T12) of KTx were collected. Parameters related to UTIs, defined by a positive urine culture associated with urinary sediment suggestive of UTI, regardless of clinical symptoms, were considered in the global FU. A number of UTIs ≥3 was considered significant during the 1st year of KTx and in the overall FU. The reduction of the eGFR/year of FU, the loss of graft and the death of KTxps with a functioning graft were evaluated as outcome.

Results
The cohort had a slight prevalence of males (59%) and a median age of 49 years. At the time of KTx, JJ ureteral stent (JJ) was placed in 38% of KTxps, with a median stay time of 47 days. During the FU, 1700 UTIs were found in 458 KTxp, 550 UTIs during the first year of KTx. The pathogens most responsible for UTIs in the global FU were Escherichia coli (61%), Enterococcus (12%) and Klebsiella (8%).
According to the number of UTIs found during the 1st year of KTx, KTxp were categorized in: UTI1≥3 (N=139) and UTI1&lt;3 (N=446). UTI1≥3 were more frequently female and older than UTI1&lt;3, had more prevalence of JJ and ATG induction therapy, and had lower hemoglobin and serum albumin at both T1 and T12. The presence of JJ, belonging to the female gender and induction therapy with ATG were the factors most correlated with IVU1≥3 (OR 1.9, 5.3 and 2.1).
The studied cohort was also categorized according to the number of UTIs during the global FU in UTItot ≥3 (N=168) and UTItot&lt;3 (N=417). UTI tot ≥3 were more frequently females, older, had a longer dialysis vintage and higher prevalence of JJ placement than UTI tot&lt;3. Furthermore, they had significantly lower hemoglobin and serum albumin values, both at T1 and T12. The presence of JJ, the female gender and age at KTx were the factors most related to UTItot ≥3 (OR 1.8, 5.9 and 1.0).
During the FU, the median absolute reduction in eGFR was found to be -0.6[-2.0; +0.9](mL/min)/years. Despite a greater reduction in glomerular filtrate rate in UTI tot≥3 group, the graft loss and the death with functioning graft had no correlation with either UTI1≥3 (7 and 5 patients, respectively) or UTItot≥3 (12 and 8 patients, respectively).
Graft loss was observed in 51 KTxps. The number of infections/follow-up time of these KTxps was comparable to that found in those who had a still functioning transplant at the end of observation, and no statistical differences were found in survival analysis according to IVU tot≥3 category.
During the global FU, 40 KTxp died with functioning graft. Also with regard to this outcome, no significant correlations were observed with the number of UTIs/follow-up time and in the survival analysis.

Conclusion
Our data confirm that UTIs are frequent in KTxps. Some factors, such as induction therapy and JJ use, certainly have a favoring effect in UTIs development. Despite the relation observed between UTIs and eGFR reduction, UTIs had no significant impact on graft loss. Beyond prevention through the improvement of lifestyles and various behavioral aspects, the implementation of personalized immunosuppressive protocols associated with a careful management of JJ are desirable interventions in order to prevent the development of UTIs in KTxps.