Incidence, Risk Factors, and Outcomes of Kidney Transplant Recipients With BK Polyomavirus-Associated Nephropathy

Abstract

Introduction: BK polyomavirus-associated nephropathy (BKPyVAN) is associated with graft dysfunction and loss; however, knowledge of immunosuppression reduction strategies and long-term graft, and patient outcomes across the disease spectrum is lacking.

Methods: This cohort study included 14,697 kidney transplant recipients in Australia and New Zealand (2005-2019), followed for 91,306 person years.

Results: BKPyVAN occurred in 460 recipients (3%) at a median posttransplant time of 4.8 months (interquartile range, 3.1-10.8). Graft loss (35% vs. 21%, P < 0.001), rejection (42% vs. 25%, P < 0.001), and death (18% vs. 13%, P = 0.002) were more common in the BKPyVAN group. The most frequent changes in immunosuppression after BKPyVAN were reduction (≤50%) in tacrolimus (172, 51%) and mycophenolate doses (134, 40%), followed by the conversion of mycophenolate to leflunomide (62, 19%) and tacrolimus to ciclosporin (20, 6%). Factors associated with the development of BKPyVAN included (adjusted hazard ratio [HR]; 95% confidence interval) male sex (1.66; 1.34-2.05), recipient age (≥70 vs. <20 [2.46; 1.30-4.65]), recipient blood group (A vs. B [2.00; 1.19-3.34]), donor age (≥70 vs. <20 [2.99; 1.71-5.22]), earlier era (1.74; 1.35-2.25), donor/recipient ethnic mismatch (1.52; 1.23-1.87), tacrolimus use (1.46; 1.11-1.91), and transplantation at a lower-volume transplant center (1.61; 1.24-2.09). The development of BKPyVAN was associated with an increased risk of all-cause (1.75; 1.46-2.09) and death-censored graft loss (2.49; 1.99-3.11), but not mortality (1.15; 0.91-1.45).

Conclusions: BKPyVAN is associated with an increased risk of all-cause and death-censored graft loss, but not death. Interventional trials are urgently needed to evaluate the efficacy of immunosuppression reduction and novel strategies to minimize the adverse outcomes associated with BKPyVAN.

Keywords: BKPyV; BKPyVAN; graft loss; kidney transplant; polyomavirus; registry.

Graphical abstract

Figure 1

Cumulative incidence of BKPyVAN. BKPyVAN, BK polyomavirus-associated nephropathy.

Figure 2

(a) Cause of death. (b) Cause of graft loss. BKPyVAN, BK polyomavirus-associated nephropathy.

Figure 3

Risk factors for the development of BKPyVAN. BKPyVAN, BK polyomavirus-associated nephropathy; CNI, x; HLA-DR, human leucocyte antigen.

Figure 4

(a) All cause graft survival. (b) Death-censored graft survival. (Continued)

Figure 4

(a) All cause graft survival. (b) Death-censored graft survival. (Continued)

Figure 5

BKPyVAN hazard ratios in each model. BKPyVAN, BK polyomavirus-associated nephropathy.

Figure 6

Cumulative incidence functions using Fine-Gray competing risk analysis comparing those with and without BKPyVAN. Graft loss and death are treated as competing events. BKPyVAN, BK polyomavirus-associated nephropathy; CI, confidence interval; HR, hazard ratio.