Are There Differences in Patient Characteristics, Treatment Patterns and Costs by Treatment Setting?
Authors: Byfield Stacey Dacosta , Reyes Carolina , Becker Laura K , Small Art 
Published: October 2019

Abstract
Abstract 4259

Background:
Few studies have examined whether differences in treatment and outcomes exist among cancer patients by the setting where care is delivered. This study investigates differences in treatment patterns, health care resource use and costs among non-Hodgkin's Lymphoma (NHL) and Chronic Lymphocytic Leukemia (CLL) patients receiving rituximab (R) or R+ chemotherapy based on site of care: office/clinic (OC) vs. hospital outpatient (HOSP).

Methods:
Patients ≥18 years with evidence of NHL or CLL diagnoses codes at least 30 days apart and received ≥2 R claims from Jan 2007 to Mar 2011 were identified from a large US commercial insurance claims database. Patients were required to be enrolled in the health plan for at least 6 months before and after the index date (date of first R claim). The follow-up period was the date of the first infusion to 30 days after the last infusion prior to a gap of ≥7 months. Patients with evidence of multiple cancers or receipt of R at both sites of care were excluded. Cohorts were created based on site of care where R was administered and type of insurance, commercial (COM) vs. Medicare Advantage (MA). Descriptive analyses were conducted to examine differences in treatment patterns and per-patient per-month (PPPM) health care costs. Multivariate analyses adjusting for age, gender, baseline Charlson index score and receipt of monotherapy was also conducted to examine differences in PPPM health care costs.

Results:
A total of 2,594 OC and 286 HOSP patients were identified. A higher percentage of Medicare Advantage patients (27% of 878 patients, n=236) received Rituxan therapy in the HOSP setting compared to commercially insured patients (2% of 2002 patients, n=50).
Among the Medicare Advantage patients, age, gender, and baseline Charlson comorbidity index were not significantly different by cohort. The mean length of the episode of care was not significantly different by site of service but the number of Rituxan infusions (5.4 vs. 6.8, p<0.01) and infusions/mth (0.99 vs. 1.27, p<0.01) were significantly less in the HOSP compared to the OC. Incidence rates of ER visits (0.11 vs. 0.08, p=0.02), but not hospitalizations were higher among the HOSP cohort. Unadjusted infusion day costs were higher among the HOSP compared to the OC ($6,479 vs. $4,998, p<0.01) but total PPPM costs were not significantly different by cohort ($9,323 vs. $10,051, p>0.05). In multivariate analyses, total PPPM costs were slightly less among the HOSP cohort (cost ratio=0.92, p<0.01).
Among the commercially insured population, gender and baseline Charlson comorbidity index were not significantly different by cohort though patients in the HOSP were slightly younger than those in the OC (55 years vs. 59 years). The mean length of the episode of care was not significantly different by site of service but compared to the OC the number of Rituxan infusions (5.52 vs. 7.56, p<0.01) and infusions per month (1.05 vs. 1.17, p>0.05) were less in the HOSP though the difference in infusions/month was not significant. Incidence rates of ER visits and hospitalizations were also not significantly different. Unadjusted infusion day costs were higher among the HOSP cohort compared to the OC cohort ($10,939 vs. $5,464, p<0.01) as well as total PPPM costs ($17,230 vs. $11,549, p=0.01). In multivariate analyses, total PPPM costs remained significantly higher among the HOSP cohort (cost ratio=1.40, p<0.01).

Conclusions:
A lower percentage of COM patients receive Rituxan infusions in the HOSP setting compared to MA patients. However, regardless of insurance type, patients in the HOSP cohort incurred greater costs on the day of Rituxan infusion compared to the OC cohort. Among MA patients, although costs incurred on the day of infusions were significantly higher in the HOSP cohort, patients treated in the HOSP setting had slightly lower total PPPM costs likely due to fewer administrations per month of Rituxan during an episode of care. Among COM patients, higher infusion day costs contributed to higher total overall costs among the HOSP cohort. These results warrant further investigation to assess the impact of these differences on clinical outcomes by site of care.

Disclosures:
Dacosta Byfield: OptumInsight: Employment, OptumInsight received payment from Genentech to conduct the study described in the abstract Other. Reyes:Genentech, Inc.: Employment, Roche Stock Other. Becker:OptumInsight: Employment, OptumInsight received payment from Genentech to conduct the study described in the abstract Other. Small:Genentech, Inc: Employment, Roche stock Other.