Late urinary tract infection after renal transplantation in the United States

Background: Although urinary tract infection (UTI) occurring late after renal transplantation has been considered "benign," this has not been confirmed in a national population of renal transplant recipients. Methods: We conducted a retrospective cohort study of 28,942 Medicare primary renal transplant recipients in the United States Renal Data System (USRDS) database from January 1, 1996, through July 31, 2000, assessing Medicare claims for UTI occurring later than 6 months after transplantation based on International Classification of Diseases, 9th Revision (ICD-9), codes and using Cox regression to calculate adjusted hazard ratios (AHRs) for time to death and graft loss (censored for death), respectively. Results: The cumulative incidence of UTI during the first 6 months after renal transplantation was 17% (equivalent for both men and women), and at 3 years was 60% for women and 47% for men (P < 0.001 in Cox regression analysis). Late UTI was significantly associated with an increased risk of subsequent death in Cox regression analysis (P < 0.001; AHR, 2.93; 95% confidence interval [CI], 2.22, 3.85); and AHR for graft loss was 1.85 (95% CI, 1.29, 2.64). The association of UTI with death persisted after adjusting for cardiac and other infectious complications, and regardless of whether UTI was assessed as a composite of outpatient/inpatient claims, primary hospitalized UTI, or solely outpatient UTI. Conclusion: Whether due to a direct effect or as a marker for serious underlying illness, UTI occurring late after renal transplantation, as coded by clinicians in the United states, does not portend a benign outcome.