Background: Monoclonal antibody treatments for metastatic colorectal cancer (mCRC) have distinct treatment-related safety profiles. This study aimed to elucidate the hospitalisation costs of adverse events (AEs) commonly associated with monoclonal antibodies when administered to patients with mCRC. Methods: This study extracted data for patients newly diagnosed with mCRC from a large US claims database from January 2005 to June 2008. The first distant metastasis diagnosis date was defined as the index date. Main outcomes were length of hospital stay (days) and hospitalisation costs (2010 US$) for AEs (identified by primary discharge diagnoses). All analyses are presented descriptively. Results: The study population (aged ≥18 years; n = 12,648) was balanced according to gender and was mainly aged 50 years or older (90.1%). Most patients had colon cancer (70.1%) as opposed to rectal cancer. Gastrointestinal (GI) perforation incurred the longest median length of stay (11.5 days) for hospitalisations, followed by wound-healing complications (7 days), arterial and venous thromboembolism (5.5 and 4 days, respectively), and congestive heart failure (4 days). The highest inpatient cost per event was for GI perforations (mean $66,224 and median $ 34,027), followed by arterial thromboembolism ($40,992 and $18,587), wound-healing complications ($36,440 and $21,163), interstitial lung disease ($26,705 and $19,111) and acute myocardial infarction ($22,395 and $15,223). Skin toxicity (mean $6475 and median $6110) and hypertension ($14,108 and $6047) were associated with relatively low costs. Conclusions: Hospital costs for monoclonal antibody treatment-related AEs in patients with mCRC vary greatly. This study provides source data for economic evaluations of head-to-head comparisons of monoclonal antibody treatments.
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