Beta Lactam and Other Antibiotic Allergies in Solid Organ and Hematopoietic Cell Transplant Recipients

Background Patients with reported beta lactam antibiotic allergies (BLA) are more likely to receive broad-spectrum antibiotics and experience adverse outcomes. Data on the burden of beta lactam and other antibiotic allergies among solid organ transplant (SOT) and hematopoietic cell transplant (HCT) recipients are limited. Methods We reviewed records of first-time adult SOT or allogeneic HCT recipients from 1/1/2013-12/31/2017 to characterize allergy labels at time of transplant. Days of hospitalization and inpatient antibiotic use for pre-specified antimicrobials were examined for the first 100 days post-transplant. Incidence rate ratios (IRR) comparing antibiotic use in BLA and non-BLA groups were calculated using negative binomial models for two metrics: days of therapy (DOT)/1000 inpatient days and percentage of antibiotic exposure days, both adjusted for transplant type, age, and cystic fibrosis diagnosis. Results Among 2153 SOT (65%) and HCT (35%) recipients, 634 (29%) reported any antibiotic allergy and 347 (16%) reported BLAs. BLA patients had significantly higher DOT for vancomycin (IRR 1.4 [1.2 – 1.7], p<0.001), clindamycin (IRR 7.6 [2.2 – 32.4], p=0.001), aztreonam in HCT (IRR 9.7 [3.3 – 35.0], p<0.001), fluoroquinolones in SOT (IRR 2.9 [2.1 – 4.0], p<0.001) and lower DOT for ampicillin-sulbactam (IRR 0.1 [0.0 – 0.4], p<0.001) and piperacillin-tazobactam (IRR 0.4 [0.2 – 0.6], p<0.001) compared to non-BLA patients; these findings were consistent when using percentage of antibiotic exposure days. Conclusions Transplant recipients have a high burden of reported antibiotic allergies, and reported BLA was significantly associated with altered post-transplant antibiotic prescribing. Pre-transplant allergy evaluation may optimize antibiotic stewardship in this population.