Background: Rasburicase is a recombinant urate-oxidase enzyme used to reduce high levels of plasma uric acid (PUA) resulting from tumour lysis syndrome (TLS). Rasburicase reduces PUA levels within 4 hours of administration, thereby minimizing the risk of serious complications from TLS. Treatment pattern analyses indicate rasburicase is often used in combination with allopurinol; however, no studies have evaluated the clinical and economic consequences of this pattern of care. The purpose of this study was to compare hospitalization costs, overall length of stay (LOS), and critical-care LOS in patients receiving rasburicase with or without allopurinol.
Methods: Hospital claims data from the Premier Perspective Database™ were used to conduct this retrospective analysis. Patients in the Premier hospital database who were administered rasburicase or combination therapy (rasburicase + allopurinol) within 2 days of hospital admission were eligible for study inclusion. Patients were excluded if they were <18 years of age or received haemodialysis (or any other renal replacement therapy support) on admission. Rasburicase patients were propensity-score-matched to combination therapy patients based on gender, race, hospital type (urban/rural, teaching), provider type, payer type, admission source, use of electrolyte modification therapy, critical-care admission and presence of a cancer diagnosis. Differences in healthcare costs, overall LOS and critical-care LOS were assessed using γ-distributed generalized linear models with a log-link function.
Results: The study population comprised 66 patients receiving rasburicase monotherapy matched to 66 patients receiving combination therapy. Mean age was 62.9 years, and 29% were female. Patients initiated on combination therapy had a shorter mean duration of rasburicase administration than patients initiated on monotherapy (2.1 vs 2.7 days) [p = 0.0059]. Additionally, rasburicase monotherapy incurred an average total cost of $US35 843 per hospitalization, compared with $US46 672 for those receiving combination therapy (p = 0.0820). Rasburicase monotherapy patients also had a shorter mean overall LOS (10.0 days vs 15.4 days; p = 0.0067). The mean critical-care LOS was similar in both cohorts (2.4 days rasburicase vs 2.9 days combination therapy; p = 0.3389).
Conclusion: Examination of claims data showed that combination therapy (rasburicase + allopurinol) trended toward higher total hospitalization costs than rasburicase monotherapy. In addition, combination therapy was associated with significantly longer overall LOS compared with upfront rasburicase monotherapy in patients at risk for developing TLS.