Risk Factors for Invasive Mold Infections and Implications for Choice of Prophylaxis after Allogeneic Stem Cell Transplantation

• Older age was an important risk factor for invasive mold infections after alloSCT.
• Other risk factors included treatment with mesenchymal stromal cells and graft-versus-host disease.
• In patients with graft-versus-host disease grade II, no invasive mold infections were seen in patients < 40 years of age compared with 14% in patients > 40 years of age.

Invasive mold infections (IMIs) are major complications after allogeneic hematopoietic stem cell transplantation (HSCT) with high mortality. We retrospectively investigated incidence and risk factors for IMI after 797 HSCTs in a center with high autopsy frequency, trying to identify patient groups that would potentially benefit from mold-active prophylaxis. The cumulative 1-year incidence of IMI was 2.1% in patients aged 21 to 40, 7.1% in patients aged 41 to 60, and 16.4% in patients > 60 years of age (P < .01 for patients aged 21 to 40 versus 41 to 60, P < .001 for patients aged 21 to 40 versus patients > 60). Risk factors for a new IMI in multivariate analysis were older age, grades II to IV acute graft-versus-host disease (GVHD) (risk hazard, 4.1; 95% CI, 1.9 to 8.8; P < .001), treatment with mesenchymal stromal cells (risk hazard, 4.0; 95% CI, 2.1 to 7.8; P < .001), transplantation with female donor to male recipient (risk hazard, 2.2; 95% CI, 1.1 to 4.3; P = .02), and hematopoietic stem cell transplantation–specific comorbidity index over 5 (risk hazard, 2.8; 95% CI, 1.1 to 6.8; P = .03). In patients with grade II acute GVHD, no IMI was seen after onset of acute GVHD in 109 HSCTs performed in patients < 40 years of age, as compared with 14 IMIs in 97 HSCTs (14%) performed in patients > 40 years of age (P < .001). To conclude, older age is an important risk factor for developing IMIs, and patients < 40 years of age with grade II acute GVHD do not appear to need mold-active prophylaxis unless receiving prolonged treatment with corticosteroids.