Trends and Cost Effectiveness of Allogeneic Stem Cell Transplant in Chronic Myelogenous Leukemia in the Era of Tyrosine Kinase Inhibitor Therapy.

Abstract

Introduction
The FDA approval of tyrosine kinase inhibitor (TKI) therapy in May 2001 dramatically affected the treatment and clinical course of patients with chronic myelogenous leukemia (CML). In this study, we examined the long-term trends in the rates of stem cell transplants (SCTs) and the mortality and clinical complications of CML following the FDA approval of Imatinib. We also compared the cost of inpatient health care, mortality, length of stay (LOS), and complications among patients who have had stem cell transplantation to those on TKI therapy.
Methods
We queried the Healthcare Cost and Utilization Project's (HCUP) Nationwide Inpatient Sample (NIS) between 1998 and 2011 using the ICD-9 code for CML (205.1) in both the primary and secondary diagnosis fields. We monitored the trends in allogenic SCT, mortality, and clinical complications related to CML. We used the information from the database between 2002 and 2011 to compare trends in hospitalizations, cost, and mortality between patients who had an allogenic transplant and those who were treated with TKI therapy.
Results
A total of 53,254 (weighted n=262,964) hospitalizations for CML (Male 54.6% and average age 65.9+/-0.8 years) occurred from 1998-2011. There has been a 408% decrease in the rate of transplants and a 79.9% (p<0.0001) decrease in in-hospital mortality since the introduction of TKIs. There has been an almost 200% reduction in blast crises, and a nearly 100% reduction in both bleeding and thrombotic complications (p-value < 0.0001). For comparing the length of stay, mortality, and cost of hospitalization, a total of 39,850 hospitalizations (weighted n = 191,285) were analyzed (male, 54.6%; age, 65.9 +- 0.08) from 2002 to 2011. The average length of stay was 7.05 days in the TKI group and 18.4 days in the transplant group. The average length of stay for the transplant procedure was 33.85 days (p<0.0001). The inpatient mortality for the transplant procedure itself was 8.9%, but was 6.3% in the group that was readmitted after having a successful transplant, and it was 7.9 % in the TKI group (p=0.032). The odds of inpatient mortality are in favor of TKI therapy with an OR of 1.9 against the transplant procedure. The average cost of hospitalization in the transplant group was $173,780, compared to $46,955 in the TKI group. The transplant procedure cost $ 338,229 (p < 0.0001).

Conclusion
The Introduction of TKIs has not only reduced the reliance on allogeneic transplants but has also led to remarkable improvement in mortality and CML-related complications. Patients on TKI therapy have a lower mortality rate, shorter length of stay, and lower hospitalization costs compared to the transplant group. The main reason for in-hospital admission for patients on TKI therapy was typically due to comorbidities of the elderly, not complications of CML. Therefore, TKI therapy is associated with improved mortality, a shorter length of hospital stay, and better cost-effectiveness.