Pre-transplant Risk Factors Can Predict Development of Acute Respiratory Distress Syndrome after Hematopoietic Stem Cell Transplantation

Acute respiratory distress syndrome (ARDS) is common complication after hematopoietic stem cell transplantation (HCT), and is a major contributor to non-relapse mortality. To better understand pre-transplant risk factors for developing ARDS following HCT. This is a single center observational study comparing risk factors for ARDS development in 164 patients who went on to develop post-HCT ARDS compared to 492 patients who did not. Patients were matched 1:3 on age, sex, type of transplant (allogeneic versus autologous) and underlying disease. Pertinent risk factors were analyzed separately in multivariable conditional logistic regression after adjustment for a priori variables known to be associated with ARDS development. ARDS patients were more likely to have lower pre-transplant pulmonary function as measured by forced vital capacity (OR 0.54 [0.42, 0.70] per liter increase in FVC, p < 0.001), forced expiratory volume in one second (OR 0.52 [0.38, 0.71] per liter increase in FEV 1, p < 0.001) and diffusing capacity (OR 0.92 [0.88, 0.96] per mL/min/mmHg increase in diffusing capacity, p < 0.001). Several laboratory indices were predictive of subsequent ARDS development including elevated AST (OR 1.01 [1.00, 1.01], p < 0.008), lower serum albumin (OR 0.44 [0.30, 0.66], p < 0.001), lower pre-transplant hemoglobin (OR 0.82 [0.73, 0.92]. p = 0.001) and lower leukocyte count (OR 0.88 [0.79, 0.99], p < 0.03). Patients who went on to develop ARDS were more likely to have been hospitalized in the year prior to transplant (OR 1.11 [1.04, 1.20], p = 0.003), and required invasive or noninvasive ventilation during that hospitalization. Lastly, ARDS patients were significantly more likely to have received carboplatin, thalidomide, methotrexate, and cisplatin compared to non-ARDS controls. Several risk factors for developing ARDS after HCT are identifiable at the time of transplantation, well before the development of critical illness and ARDS. The identification of risk factors long before ARDS develops is relatively unique to the HCT population. Further work is needed to develop usable risk prediction tools in this setting.