Economic burden of adverse events in patients with metastatic renal cell carcinoma

Although targeted therapies (ie, tyrosine kinase inhibitors and antiangiogenesis agents) are effective as first-line treatment of metastatic renal cell carcinoma (mRCC), moderate-to-severe adverse events have been reported in clinical trials of these agents. Information concerning the economic burden of these events is limited.

The purpose of this study was estimate the costs associated with adverse events in patients with mRCC receiving selected targeted agents indicated for first-line treatment of this disease.

Retrospective study based on health care claims data for patients with mRCC, aged ≥18 years, receiving first-line treatment with targeted therapies. Adverse events of interest included abdominal pain, back pain, diarrhea, dyspnea, extremity pain, fatigue and/or asthenia, hand-foot syndrome, hypertension, lymphopenia, nausea and/or vomiting, neutropenia, proteinuria, and thrombocytopenia. Patients receiving care for these events were identified using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes on health care claims. Costs were examined during a 30-day period, beginning with date of first mention of each event; nonevented patients similarly were assigned a shadow index date. We estimated total costs during 30 days after the index date for patients with and without adverse events, excluding the costs of targeted therapy.

Sixty-four percent of patients receiving targeted therapies for mRCC had health care encounters for ≥1 adverse events. Events that occurred with a frequency >20% included severe abdominal pain, back pain, fatigue and/or asthenia, and nausea and/or vomiting, respectively; 10% to 20% of patients had encounters for diarrhea, dyspnea, and extremity pain, respectively. Mean (SD) total costs of care during the 30-day, postevent period were substantially higher among patients with versus without adverse events-$12,177 ($19,621) versus $4070 ($8142). Adjusting for differences in baseline characteristics, the estimated cost difference was $11,373 (95% CI, $5286-$21,419).

Costs of adverse events are substantial in patients receiving targeted therapies, specifically, sunitinib, sorafenib, or bevacizumab, for mRCC. Efforts to prevent and/or better manage these events may reduce health care costs.