The Economic Burden of Pleural Effusions (PE) In Patients with Chronic Myeloid Leukemia (CML).
Authors: Wu Eric Qiong , Guerin Annie , Bollu Vamsi , Williams Denise , Guo Amy , Barido Diego Ponce de Leon , Yu Andrew Peng , Quintás-Cardama Alfonso 
Published: October 2019

Abstract
Abstract 3841

Background:
Ph+ CML patients may develop PE, as an adverse event of some tyrosine kinase inhibitors (TKI) drug therapy. PE is characterized by an excessive accumulation of fluid in the fluid-filled space that surrounds the lungs. PE requires medical care, may compromise the course of CML treatment, and have economic consequence beyond the costs of treating PE.

Aim:
To compare healthcare resource utilization and costs between CML patients treated with a TKI who developed PE and their matched PE-free controls.

Methods:
MarketScan and Ingenix Impact databases (2001-2009) were combined to identify adult CML patients (ICD-9CM code 205.1×) who received ≥1 prescription of imatinib, dasatinib, or nilotinib before the index date and had continuous enrollment ≥6 months prior to and after the index date. The index date was defined as 30 days before the first PE diagnosis (ICD-9CM code 511.9×) for patients with PE and was randomly selected among all the eligible calendar dates (i.e., following a prescription for a TKI and a diagnosis for CML) for the PE-free controls. Patients were followed for 6 months after the index date. PE and PE-free patients were matched on a 1:1 ratio using propensity score matching. PE-related (i.e., medical claims with a PE diagnosis) resource utilization (inpatient [IP], outpatient [OP], emergency room [ER] and other medical visits) and costs were estimated for PE patients. To estimate the overall incremental impact of PE, all-cause and CML-related (i.e., medical services associated with a diagnosis code of 205.1×) resource utilization and costs were compared between PE and PE-free controls. All costs were reported in 2009 US dollars. Incidence rate ratios (IRR) for healthcare resource utilization were estimated by Poisson regression models. Incremental costs were estimated using generalized linear models or two-part models. Multivariate regression models controlled for age, gender, treatment duration with tyrosine kinase inhibitor, other chemotherapy, bone marrow or stem cell transplant, CML complexity, Charlson comorbidity index, adverse events, and comorbidities.

Results:
The study included 179 matched pairs. On average, patients were 63.4 and 63.8 years old with 41% and 49% of the population being female for PE-free and PE patients, respectively. During the study period, PE patients were estimated to have an average of 0.62 PE-related IP admissions, 8.43 IP days, 0.06 ER admissions, and 1.76 OP visits. Compared to PE-free patients, PE patients had more than 7 times as many IP days (IRR=7.23; p<.01), almost 3 times as many IP admissions (IRR=2.96; p<0.01), almost twice as many OP visits (IRR=1.98; p<.01) and ER visits (IRR=1.77; p<.01). Especially, PE patients had almost 10 times as many CML-related IP days (IRR=9.91; p<.01), more than 3 times as many CML-related IP admissions (IRR=3.95; p<0.01), twice as many CML-related OP visits (IRR=2.16; p<.01), and almost 6 times as many CML-related ER visits (IRR=5.60; p<.01). On average, PE-related medical costs were estimated at $11,015 per patient, where 84.2% was accounted for by IP costs. Total costs for all-cause related medical services were estimated at $37,566 for PE patients and $14,841 for PE-free patients. After adjusting for confounding factors, the incremental total medical cost of PE patients was $22,299 (p<.01), mostly due to the incremental OP cost ($12,931; p<.01) and IP cost ($8,737; p<.01). Similarly, PE patients incurred higher CML-related medical costs compared to PE-free patients, with a $15,859 (p<.01) incremental cost.

Conclusion:
Compared to PE-free patients, PE patients have a substantial economic burden with higher PE-related costs, CML-related costs, and total medical cost.

Disclosures:
Wu: Analysis Group, Inc.: Employment. Guerin:Analysis Group, Inc.: Employment. Bollu:Novartis: Employment, Equity Ownership. Williams:Novartis: Employment, Equity Ownership. Guo:Novartis Pharmaceuticals Corporation: Employment, Equity Ownership. Ponce de Leon Barido:Analysis Group, Inc.: Employment. Yu:Analysis Group, Inc.: Employment.