Delirium and Healthcare Utilization in Patients Undergoing Hematopoietic Stem Cell Transplantation

Background: Delirium, a common neuropsychiatric syndrome among hospitalized patients, has been associated with significant morbidity and mortality. Although often reversible with prompt diagnosis and appropriate management (e.g., with antipsychotic medications), data regarding the prevalence of delirium and its association with clinical outcomes and health care utilization among patients undergoing hematopoietic stem cell transplantation (HSCT) are lacking.

Methods: We conducted a retrospective cohort study of 502 patients admitted for their index allogeneic or autologous HSCT hospitalization at two tertiary care hospitals in Boston from April 2016 to April 2021. We used Natural Language Processing (NLP) to identify patients with delirium (present or absent as defined by NLP-assisted chart review of the electronic health record) and those who were prescribed common antipsychotic medications. Multivariable regression models were used to examine the association between delirium and health care utilization controlling for various sociodemographic and clinical factors.

Results: Among 502 patients (median age=62; 40.6% female) undergoing allogenic and autologous HSCT, 44.4% (n=124/279) and 39.0% (n=87/223), respectively, were coded to have delirium during their index HSCT hospitalization. 51.2% (N=257) of our sample were prescribed an antipsychotic medication. Of the 211 (42%) of our sample who were coded to have delirium, 72 (34%) were not prescribed an antipsychotic medication. In multivariable analysis, delirium was associated with antipsychotic prescription in patients undergoing autologous (OR 3.613, p<0.001) and allogeneic (OR 2.804, p<0.001) transplant. Delirium was also associated with increased length of stay (LOS) during index transplant hospitalization for patients undergoing autologous (b=2.204, p<0.001) and allogeneic (b=7.960, p<0.001) transplant. Delirium was not associated with increased likelihood of palliative care consultation for both allogeneic and autologous groups, but was associated with psychiatry consultation (OR 6.148, p=0.002) during index hospitalization in those undergoing allogeneic transplant.

Conclusion: We found that 42% patients undergoing HSCT had delirium during their index hospitalization, and that delirium was associated with increased LOS during index hospitalization, as well as increased likelihood of antipsychotic medication usage. Our findings underscore the need to better identify patients at risk for delirium and assess for and manage delirium in patients undergoing HSCT since it negatively impacts health care utilization in this population.