Characterizing the landscape and impact of infections following kidney transplantation

Abstract

Infections remain a major threat to successful kidney transplantation (KT). To characterize the landscape and impact of post-KT infections in the modern era, we used United States Renal Data System (USRDS) data linked to the Scientific Registry of Transplant Recipients (SRTR) to study 141 661 Medicare-primary kidney transplant recipients from January 1, 1999 to December 31, 2014. Infection diagnoses were ascertained by International Classification of Diseases, Ninth Revision (ICD-9) codes. The cumulative incidence of a post-KT infection was 36.9% at 3 months, 53.7% at 1 year, and 78.0% at 5 years. The most common infections were urinary tract infection (UTI; 46.8%) and pneumonia (28.2%). Five-year mortality for kidney transplant recipients who developed an infection was 24.9% vs 7.9% for those who did not, and 5-year death-censored graft failure (DCGF) was 20.6% vs 10.1% (P < .001). This translated to a 2.22-fold higher mortality risk (adjusted hazard ratio [aHR]: _2.15 2.22_2.29 , P < .001) and 1.92-fold higher DCGF risk (aHR: _1.84 1.91_1.98 , P < .001) for kidney transplant recipients who developed an infection, although the magnitude of this higher risk varied across infection types (for example, 3.11-fold higher mortality risk for sepsis vs 1.62-fold for a UTI). Post-KT infections are common and substantially impact mortality and DCGF, even in the modern era. Kidney transplant recipients at high risk for infections might benefit from enhanced surveillance or follow-up to mitigate these risks.

Figure 1.. Cumulative incidence of an infection after kidney transplantation.

The cumulative incidence of a post-KT infection was 36.9% at 3 months, 45.1% at 6 months, 53.7% at 1 year, 69.6% at 3 years, and 78.0% at 5 years.

Figure 2.. Incidence of different infection types after kidney transplantation

UTI; urinary tract infection; CMV, cytomegalovirus; C. Diff, Clostridium difficile There was wide variation in the type of infections that KT recipients developed. The most common post-KT infections were urinary tract infection (46.8% of KT recipients developed), other bacterial (31.6%), and pneumonia (28.2%), whereas the least common post-KT infections were fungal (3.5%), meningitis (1.6%), and zoonotic (0.2%).

Figure 3.. Mortality and death-censored graft failure in KT recipients who developed an infection and those who did not.

Mortality and death-censored graft failure was significantly higher for KT recipients who developed an infection (solid line) compared to those who did not (dashed line). For example, 10-year mortality was mortality was 45.8% vs. 20.7%, and 10-year death-censored graft failure was 32.7% vs. 19.8% (p<0.001 for both).