Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.
A Cost Effectiveness Analysis of Weekly Complete Blood Count Monitoring for Leukopenia In Patients with Granulomatosis with Polyangiitis (Wegner's) On Cyclophosphamide.
Khasnis1, Atul A., Wilson2, Richard, Hoffman1, Gary S., Villa-Forte1, Alexandra, Langford3, Carol A.
Daily cyclophosphamide (CYC) is used in the management of patients with severe granulomatosis with polyangiitis (Wegener's) (GPA). Leukopenia is a common toxicity of daily CYC which can be associated with infectious complications; however, no evidence based guidelines exist for white blood count monitoring in these patients. We assessed the cost-effectiveness of weekly compared to monthly complete blood count (CBC) monitoring in patients with severe GPA receiving oral CYC.
The two CBC monitoring approaches for surveillance of leukopenia and its consequences were compared using a decision analysis model created using TreeAge Pro 2009. The parameters for prevalence of leukopenia, infections, and outcomes were obtained from an existing registry at the Cleveland Clinic (130 patients) and literature review of studies using daily CYC for management of severe GPA as well as the literature on outcomes in patients with sepsis. Only studies clearly documenting the frequencies of parameters required in the model and the relationship between severe leukopenia and severe infection were included. Parameter values that were unavailable from the published literature were entered by consensus and subjected to wide ranges for sensitivity analyses. Costs were in dollars (2010) and effectiveness as quality-adjusted life-years (QALYs) gained. Analysis was performed from a societal perspective. In addition to a baseline cost effectiveness analysis, we performed univariate sensitivity analyses and probabilistic sensitivity analysis (PSA) to check for robustness of the parameters included in the analysis. Although the base case patient was 45 years old, we analyzed the results over a wide range of patient ages (2565 years).
The expected utility of weekly CBC monitoring of these patients for leukopenia is 18.74 QALYs versus 18.52 QALYs with monthly CBC. The expected gain is 0.22 QALYs and incurs $489 lower cost per patient. The weekly CBC strategy dominated (was more effective and less expensive than) the monthly CBC strategy. In clinical scenarios generated by the univariate sensitivity analyses where the weekly strategy did not dominate the monthly strategy, it was still more effective but as or more expensive than the monthly CBC strategy. The results were not sensitive to changes in patient age. The acceptability curve generated by PSA also demonstrated dominance of the weekly CBC strategy.
Weekly CBC monitoring appears to be cost-effective for prevention of severe leukopenia and severe infections in patients on daily CYC for GPA. Further prospective studies with systematic data collection regarding frequencies of parameters in the model are required to confirm and validate our findings.
To cite this abstract, please use the following information:
Khasnis, Atul A., Wilson, Richard, Hoffman, Gary S., Villa-Forte, Alexandra, Langford, Carol A.; A Cost Effectiveness Analysis of Weekly Complete Blood Count Monitoring for Leukopenia In Patients with Granulomatosis with Polyangiitis (Wegner's) On Cyclophosphamide. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :2375