Defining the Cost Variation by Site-of-Care for Radiotherapy: A Claims-Based Analysis

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<h3>Purpose/Objective(s)</h3> To understand the qualitative differences in total cost of care between sites of care (SOC) in patients undergoing radiation therapy (RT). <h3>Materials/Methods</h3> This retrospective cohort study includes lung, esophageal, pancreatic, rectal and head and neck cancer patients throughout the US insured by a large health plan from 1/1/18 to 12/31/21. We defined total same-day visit costs (TVC) as all radiation costs incurred in the visit, total RT cost of care (TRC) as the total RT costs incurred between the first and last RT visit and total cost of care (TCC) as the total cost of care for all medical and pharmacy benefits incurred between the first and last RT visit. Costs were compared by SOC (outpatient-office (OO) vs. outpatient-hospital (OH)). We used a t-test for univariate analysis and multivariate linear regression to predict the continuous outcomes of TVC, TRC and TCC. We evaluated the performance of the TVC regression overall and by local market to assess regional cost differences where p<0.05 and R²>0.50 were deemed significant. <h3>Results</h3> We evaluated 16,818 patients in our study. In unadjusted analyses, treatments rendered in the OH cost significantly more than those rendered in the OO. We observed an extremely weak correlation between the distance from home-to-SOC for TVC (r=0.031), TRC (r=0.031) and TCC (r = 0.036). In multivariate regression models, treatments in the OH setting cost more than those rendered in the OO setting by $295.18 (TVC, 61.6% more), $5,857.64 (TRC, 57.1% more) and $7,882.93 (TCC, 31.6% more). Variables highly predictive of cost increases in TVC, TRC and TCC include receiving care in an OH setting, being commercial fully insured, median income (measured as US Census reported ZIP CODE median), chemotherapy and hydration. Malnutrition (defined as having a malnutrition diagnosis in the last 30 days) had a significant impact on costs in all models; in the TVC and TRC models, it reduced costs whereas in the TCC model it increased costs. Likewise, palliative care had a significant impact on all models; in the TVC model, it increased costs. In the TRC and TCC models, it reduced costs. The local market analysis of the TVC model identified unusual cost variation between OO and OH visits not observed in the overall model with maximum variations in the local market ranging from -$0.5k to $20k from the original model's coefficient. In addition, the TVC model shows the home-to-index SOC coefficient as $0.07/mile but larger variation at the local level up to $44,230/mile. <h3>Conclusion</h3> In this study, radiotherapy costs are highly variable based on local markets. OH treatment setting, being commercial fully insured, median income, chemotherapy and hydration predicted higher costs. Home-to-index SOC distance is not operationally impactful at the national level but is important in select regional communities. Further investigation is needed to define this variability and to define opportunities for standardizing the cost of radiotherapy delivery while improving access and quality of care.