Outcomes of Kidney Transplantation in Cystic Fibrosis

BackgroundCystic fibrosis (CF) is a chronic multisystem disease with features including recurrent pulmonary infection, bronchiectasis, malnutrition, and alterations in drug metabolism which may discourage referral and listing for kidney transplantation. Although no specific renal phenotype is identified in CF, chronic kidney disease (CKD) occurs in young people and adults with CF with greater frequency than in the general population. The characteristics and outcomes of kidney transplantation in the CF population have not been previously described. MethodsWe used de-identified data supplied by the US Renal Data System (USRDS) to compare persons with end stage kidney disease (ESKD) with first kidney transplant, who did and did not have a diagnosis of CF. We compared demographic and clinical characteristics, mortality, patient survival, and death-censored graft survival using linear and logistic regression, multivariable logistic regression models, and Kaplan-Meier and log-rank tests with stratification/binning by propensity scores. ResultsOf those with dual diagnoses of CF and ESKD, half received a first kidney transplant. CF was independently associated with higher odds of receiving a living donor transplant. Those with a kidney transplant were younger than both those who did not have CF and those with CF without transplant and had higher odds of being female. Those with dual diagnoses of CF and ESKD had disproportionately lower odds of being identified as Black or African American relative to their representation in the population of all with CF and ESKD. Diabetes was more frequently a diagnosis and primary cause of ESKD in people with CF, but was approximately half as frequently the primary cause of ESKD as in those without CF. Complications of transplantation, particularly lung, were the second most frequent etiology of ESKD in people with CF. Overall survival with ESKD was 21.1 years for those with CF and 31.8 for those without CF. The survival benefit associated with transplant was 17.2 years for those with CF and 24.8 years for those without CF. Death censored median graft survival was significantly longer for those with CF, 20.4 vs 13.7 years. ConclusionsCF is a chronic multisystem disease with features which may discourage referral and listing for kidney transplant. We used de-identified data from the USRDS datasets to describe the characteristics and outcomes of all unique individuals with the diagnosis of CF and first kidney transplant prevalent during the five-year period 2014 and 2018. Those with CF had similar odds to those without CF or receiving a first kidney transplant, and higher odds of receiving a living donor graft. Diabetes mellitus was significantly less frequently the primary cause of ESKD in those with CF and kidney transplant. Complications of solid organ transplant, particularly lung, were the second most frequent cause of ESKD in people with CF and kidney transplant. Median patient survival following the first kidney transplant was significantly shorter than for those who did not have CF, but was substantial, as was the survival advantage when compared to dialysis. Median graft survival was significantly longer for those with CF. It is our hope that this data will improve awareness of kidney disease in persons living with CF and their care teams, and encourage early referral to nephrology and transplant centers, and positive consideration of wait listing for kidney transplantation.