Methods: Using a decision-analytic approach, we synthesized the best available data to model the clinical course of CHF in a cohort of patients similar to those in the Childhood Cancer Survivors Study (CCSS). We used a simulation model to project lifetime CHF risk, life expectancy (LE), lifetime costs and incremental cost-effectiveness ratios (ICERs) associated with interval-based cardiac assessment. Compared to no assessment, we estimated the incremental benefit of an echocardiogram every 1, 2, 5 or 10 years. Test performance (sensitivity=0.53, specificity=0.86) and absolute excess risk (AER) for CHF incidence were based on CCSS estimates, while a broader range of data were used to establish baseline assumptions, including: 1) ALVD progresses to CHF after a median interval of 5.9 years and 2) ACEI treatment for ALVD reduces CHF risk (RR=0.67). Screening and treatment costs were based on Medicare reimbursement rates.
Results: For a cohort of 5-year childhood cancer survivors (diagnosis age=10), the expected CHF-related mortality was 18.8%. Routine echocardiogram reduced lifetime CHF risk by 4.9% (every 10 years) to 11.9% (every 1 year). Compared to no assessment, the ICER for assessment every 10 years was $188,900 per LE gained. ICERs for all other strategies exceeded $200,000 per LE gained. Results were most sensitive to AER for CHF among CCSS, ACEI treatment effectiveness and echocardiogram specificity. Prevalence of individuals with false positive test results varied by strategy, ranging from 13% (every 10 years) to 91% (every 1 year) at 45 years of age. Based on probabilistic sensitivity analysis, the probability that assessment every 10 years was optimal given a cost-effectiveness threshold of $150,000 per QALY was only 2%.
Conclusions: Recommended follow-up guidelines for cardiac assessment may improve overall survival for childhood cancer survivors, but less frequent screening than currently recommended is likely optimal.