Kidney Failure in Persons With Cystic Fibrosis

Rationale & Objectives Chronic kidney disease (CKD) occurs with increased frequency in people with cystic fibrosis (PwCF). CKD may progress to kidney failure. We sought to describe the prevalence, characteristics and outcomes of kidney failure in PwCF. Study Design Retrospective cohort study using data supplied by the US Renal Data System (USRDS), a virtually complete record of all US persons with kidney failure. Setting & Participants All unique deidentified persons listed in the USRDS Patient and Hospitalization Standard Analytic Files (SAFs) 2014-2018. Outcomes Estimated prevalence of kidney failure in cystic fibrosis (CF) and non-CF cohorts. Comparisons between PwCF and non-CF concerning demographics, primary cause of kidney failure, diabetes and organ transplant status, mortality and survival since onset of kidney failure. Analytical Approach Linear and logistic regression, propensity score-matched Kaplan-Meier survival curves, and log-rank tests. Results We estimated the prevalence of kidney failure to be 22.6 to 29.3 times greater in PwCF than in the general US population. Diabetes was the primary cause of kidney failure in 24.3% of PwCF and 42.3% of non-CF (OR 0.56; 0.44,0.71 p < 0.001). Complications of lung transplantation were the primary cause in 16.9% of PwCF and 0.03 % of non- CF (OR 682; 501,929 p < 0.001). Overall median survival with kidney failure was 12.6 years for PwCF and 11.8 years for non-CF (p 0.96) Limitations USRDS data are limited to Medicare claims. Conclusions People with CF (PwCF) had increased prevalence of kidney failure relative to the non-CF US population. The profile of primary causes of kidney failure in PwCF differed from the non-CF population. Diabetes was half as frequently and transplant of lung and other organs markedly more frequently primary causes in PwCF. Overall median survival with kidney failure was not significantly different between PwCF and matched non-CF. Plain-Language Summary People with cystic fibrosis have an increased rate of chronic kidney disease which can progress to kidney failure requiring dialysis or kidney transplant. We investigated kidney failure in people with cystic fibrosis using a large national registry. The risk of kidney failure was greater in those with cystic fibrosis than the general population. The cause of kidney failure was more frequently complications of lung transplant and less frequently diabetes in those with cystic fibrosis. The length of time that people survived after developing kidney failure was not significantly different between people with and without cystic fibrosis. We recommend routine monitoring of kidney function in people with cystic fibrosis, and consideration of interventions which reduce the risk of kidney failure.