BK Virus Epidemiology, Risk Factors, and Clinical Outcomes: An Analysis of Hematopoietic Stem Cell Transplant Patients at Texas Children's Hospital

Background. BK virus-associated hemorrhagic cystitis (BKV-HC) is a serious complication after hematopoietic stem cell transplantation (HSCT). Methods. A retrospective review was performed to determine the frequency of BKV-HC and identify risk factors and renal morbidity associated with BKV-HC in pediatric HSCT recipients at our institution. Results. A total of 314 pediatric recipients underwent allogeneic HSCT for either malignant (173, 55.1%) or nonmalignant disorders (141, 44.9%) from January 1, 2011, to December 31, 2015, with a minimum follow-up of 5 years post-HSCT. Severe BKV-HC (grades 3 and 4) was prevalent in 46 out of 67 (68.7%) recipients. Timing to presentation of severe BKV-HC (grades 3 and 4) occurred at a median of 37 days (26, 74; IQ1, I Q3) post-HSCT, with the duration of macroscopic hematuria lasting a median of 37.5 days (18, 71; IQ1, I Q3). In the first 60 days post-HSCT, peak acute kidney injury (AKI) stages 2 and 3 were seen more frequently in HST recipients who developed BKV-HC than those without (P = .004). Similarly, during post-HS degrees . days 61 to 100, peak AKI stage 3 was also more frequently seen in HSCT recipients who already developed BKV-HC prior to or during this time period than those without BKV-HC (P = .0002). Recipients who developed BKV-HC within 1 year of HSCT had more frequent mild to moderate chronic kidney disease (CKD stages 2-3) than those without BKV-HC (P = .002 and .007, respectively). On multivariate analysis, BKV-HC was associated with all-cause mortality (hazard ratio [HR]: 2.22; 95% confidence interval [CI]: 1.35-3.65). The following clinical variables were associated with time to development of HC on multivariate analysis: age (subdistribution HR [sH R] 1.11; 95% CI: 1.06-1.16) and myeloabalative conditioning regimen (sHR 4.2; 95% CI: 2.12-8.34). Conclusions. Pediatric HSCT patients with BKV-HC experience significant morbidity and mortality. Renal morbidity, including AKI and CKD, is associated with BKV-HC.

Automated summary

Severe BKV-HC in pediatric HSCT recipients is associated with significant renal morbidity, including AKI and CKD, as well as increased risk of mortality. Factors such as age and myeloablative conditioning regimen are predictive of time to development of BKV-HC.