Risk factors associated with invasive fungal infections in kidney transplant patients

Abstract Background Kidney transplant recipients are at increased risk for developing invasive fungal infections (IFI). We queried the United States Renal Data System (USRDS) for risk factors for IFI in these patients. Methods Patients who underwent a kidney transplant between 2005-2008 were queried for an IFI diagnosis using ICD-9 codes. An IFI was defined as at least one documented diagnosis from one of the following: 1) Candida (candidemia); 2) histoplasmosis; 3) aspergillosis; 4) cryptococcosis; 5) “Other” mycoses. Potential risk factors included demographics, certain co-morbidities, and immunosuppressive medications. To examine the relative risk (RR), simple bivariate models were used, followed by a comprehensive full model to estimate the adjusted RR (aRR). Results 1,218/57,188 kidney transplant patients had 1,343 IFI diagnoses, with a median time to infection of 495 days. "Other" mycoses accounted for the most IFI diagnoses (37%), followed by aspergillosis (22%). The risk for any IFI was increased with age ≥65 years. Diabetes (aRR=1.71), bacterial pneumonia (aRR=1.62), and UTI (aRR=1.34) were the top 3 clinical risk factors for infection. Each of the IFI groups were also associated with individual risk factors. Therapy with mycophenolate mofetil was associated with a decreased risk of candidemia. Conclusion Risk factors for IFI in renal transplant patients include demographic, medication-associated, and clinical data, as well as organism-specific factors. These results offer an extensive clinical profile of risk for IFI, and may thus help inform the diagnosis and presumptive therapy of invasive fungal infections in renal transplant recipients.