Introduction: Kidney stone disease is common and can lead to complications such as urinary tract obstruction, infection, and acute kidney injury. In kidney transplant recipients, complications from kidney stone events may lead to reduced allograft function. Clinical outcomes associated with kidney stone events in kidney transplant recipients such as acute kidney injury, urinary tract infections and hospitalization rates remain unknown. Methods: We used data from the United States Renal Data System to identify adult patients who received their first kidney transplant between January 1st, 2007, and December 31st, 2018. Patients were included if they had uninterrupted Medicare Part A and B for at least six months prior to kidney transplant. We identified transplant patients who were hospitalized with a primary diagnosis of kidney stone disease and transplant patients with acute kidney injury and urinary tract infections using inpatient and outpatient International Classification of Diseases, Ninth and Tenth Revision (ICD-9/ICD-10) claims-based algorithms. Results: We identified 83,535 patients who received a kidney transplant. The incidence of kidney stone events was 1.7% (1,436) in the 3 years after transplant. The median time from transplant to a kidney stone diagnosis was 0.61 (25%,75% range 0.19-1.46) years. The proportion of patients with a kidney stone event who were hospitalized was 39% (556/1436). Approximately 35% (508/1436) of kidney transplant patients had acute kidney injury and 4% (64/1436) had a urinary tract infection associated with a kidney stone event. Conclusions: Hospitalization and acute kidney injury are not rare events in kidney transplant patients who experience a kidney stone. These findings suggest that kidney transplant recipients who are at risk for kidney stone disease may benefit from closer monitoring of complications associated with kidney stone disease. Future work to assess long-term changes in allograft function in transplant patients with stone disease and the impact of stone recurrence in these patients is needed. SOURCE OF Funding: Department of Veterans Affairs Merit Review (I01 HX003091 to ACP and JTL) and the National Institutes of Diabetes and Digestive and Kidney Diseases (K23DK128651 to CG).
