Abstract
BACKGROUND: The risk factors and outcomes associated with severe persistent BK polyomavirus (BKPyV) in kidney transplant recipients (KTR) are unknown. METHODS: This is a single-center retrospective study of KTR with severe persistent BKPyV compared to (1) KTR with low/no BKPyV-DNAemia and (2) KTR with high BKPyV-DNAemia. Severe persistent BKPyV was defined as BKPyV load reaching > 6 log(10) (1 000 000 copies/mL) for ≥ 90 days. Low/no BKPyV was defined as BKPyV load remaining < 3 log(10) (1000 copies/mL), and high BKPyV was defined as BKPyV load ≥ 3 log(10) without meeting criteria for severe persistent BKPyV. RESULTS: Out of 2586 KTR, 22 had severe persistent BKPyV and were compared to 1843 KTR with low/no BKPyV and 721 KTR with high BKPyV. A low absolute lymphocyte count during the first month posttransplant was associated with an increased risk of severe persistent BKPyV relative to those with low/no BKPyV and high BKPyV (OR 0.91, 95%CI 0.84, 0.99). KTR with severe persistent BKPyV had significantly lower eGFR at 2 years posttransplant relative to low/no and high BKPyV groups eGFR (36 vs. 61 and 59 mL/min; p < 0.001 for both). Additionally, KTR with severe persistent BKPyV required more lab draws and incurred significantly higher total lab-associated costs relative to KTR with low/no BKPyV and high BKPyV ($7516 vs. $4631, p < 0.001; $7516 vs. $5811, p < 0.001, respectively). CONCLUSIONS: Severe persistent BKPyV is uncommon but associated with poor outcomes including impaired renal function, a higher burden of labs, and lab-associated costs. Future studies are needed to determine underlying factors that predict severe persistent BKPyV.