Economic burden of adverse events in patients with metastatic renal cell carcinoma (mRCC).

Abstract

e16573 Background: To estimate costs associated with adverse events (AEs) in patients receiving targeted therapies indicated for first-line treatment of mRCC. Methods: A retrospective study using a large US healthcare claims database (PharMetrics) from 1/2000 to 12/2009 was conducted. Study subjects were aged ≥18 years, had mRCC, and received first-line treatment with targeted therapies. AEs of interest comprised abdominal pain, back pain, diarrhea, dyspnea, extremity pain, fatigue/asthenia, hand-foot syndrome, hypertension, lymphopenia, nausea/vomiting, neutropenia, and proteinuria. Patients receiving care for these AEs were identified using ICD-9-CM diagnosis/procedure codes on healthcare claims. Costs were examined over a 30-day period, beginning with date of first mention of each AE; non-evented patients were assigned a “shadow” index date for comparison purposes. We estimated total costs over 30 days following the index date for patients with and without AEs, on both unadjusted basis and following adjustment for differences in baseline characteristics using a generalized linear model (GLM). Direct costs of targeted therapy were not considered. Results: Among patients receiving targeted therapy for mRCC, 64% had healthcare encounters for one or more AEs. AEs occurring with frequency >20% included severe abdominal pain, back pain, fatigue/asthenia, and nausea/vomiting, respectively; 10-20% of patients had encounters for diarrhea, dyspnea, and extremity pain, respectively. Mean [SD] total costs of care during the 30-day, post-index period were substantially higher among patients with AEs ($12,177 [$19,621] vs $4070 [$8142] for those without AEs). Adjusting for differences in baseline characteristics, the estimated cost difference (95% CI) was $11,373 ($5286 - $21,419). Conclusions: Costs associated with AEs of first-line targeted therapies are substantial in patients with mRCC. Efforts to prevent and/or better manage these events may reduce healthcare costs.