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The Cost Effectiveness of RSV Prophylaxis: Using Decision Analysis to Build a Better Guideline. Melony E. S. Sorbero, PhD, MS, MPH. Purpose . To evaluate the cost effectiveness of current AAP recommendation for use of RSV prophylaxis. Focus on premature infants without CLD.
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The Cost Effectiveness of RSV Prophylaxis: Using Decision Analysis to Build a Better Guideline Melony E. S. Sorbero, PhD, MS, MPH
Purpose • To evaluate the cost effectiveness of current AAP recommendation for use of RSV prophylaxis. • Focus on premature infants without CLD. • Identify more cost-effective alternative recommendations.
Background • Respiratory syncytial virus (RSV) is the primary cause of lower respiratory tract illness in young children. • Generally resolves uneventfully in otherwise healthy children. • High risk populations may develop severe and sometimes fatal lower respiratory tract infections. • RSV infection annually contributes up to 126,300 pediatric hospitalizations in the U.S. • Estimated annual hospitalization costs for RSV pneumonia in children <=4 years: $300 - $400 million (1998 $)+. • Annual mortality due to RSV in infants and children is estimated to range from 200 ++ to over 2,700 +++. (+Howard et al. J of Peds 2000; ++Shay DK et al. J Infect Dis 2001; +++ Institute of Medicine. In: New Vaccine Development: Establishing Priorities: Vol I. Wash DC Nat Aca Press 1986)
Background • There may also be long-term health consequences due to severe RSV infections: • Increased risk of asthma and other respiratory conditions • Duration of increased risk up to 10 years • A causal relationship between morbidity and severe RSV infection has not been shown. (Meissner HC at al. Pediatr Infect Dis J. 1999; Sigurs et al. Am J Resp Crit Care Med 2000; Sampalis J Pediatr 2003 )
Background • Prematurity increases risk of severe RSV infection. RSV Hospitalization Rate by Gestational Age at Birth (Stevens TP et al. Arch Ped Adoles Med 2000)
Background • Worldwide RSV epidemics occur yearly • United States: November – April • Peak: January – March (most areas) • Peak: 2 – 3 months earlier (Southeast) • 80% RSV admissions occur within 4 months discharge from NICU. Respiratory Illness Hospitalization Rate by Month of Discharge from NICU in Infants <= 32 Weeks GA (Cunningham CK, McMillan JA, Gross SJ Pediatrics 1991)
Background • No vaccine available for RSV. • 2 products available in U.S. for passive immuno-prophylaxis against RSV. • Respiratory Syncytial virus immunoglobulin intravenous (RSV-IGIV) (RespiGam; MedImmune, Inc, Gaithersburg, MD), containing high-titer RSV antibodies. • Palivizumab, (Synagis; MedImmune, Inc, Gaithersburg, MD),is a humanized monoclonal antibody that binds to the F-protein of RSV. • Require monthly treatments during RSV season. • Synagis less costly and more effective of two.
American Academy of Pediatrics (AAP) Recommendations for Prophylaxis Use • Released in 1998; updated in 2003. • Infants younger than age 2 years who currently receive or have recently required medical therapy for CLD. • Infant born 28 weeks gestation who are 12 months old at the start of the RSV season. • Infants born at 29 to 32 weeks who are 6 months old at the start of the RSV season. • Infants born between 32 and 35 weeks of gestation with risk factors. (Red Book, 2000)
Synagis • Efficacy of Synagis in prevention of severe RSV infection in premature infants without CLD: 82%. • Synagis is available in 50 and 100 mg vials. • The cost is $725 per 50 mg and $1370 per 100 mg vial. • Synagis has a shelf life of 6 hours making drug wastage nearly inevitable.
Study Design • Developed decision analytic model. • Societal perspective. • Two versions: w/ and w/o asthma. • Impact of asthma modeled with semi-Markov processes. • Conducted CEA on models with asthma; CBA on models w/o asthma. • Seven hypothetical cohorts of premature infants without CLD born at 24 – 32 weeks gestational age (GA). • Assumed discharged from NICU at 36 weeks post-conceptual age.
Model Assumptions • Risk of RSV hospitalization obtained from published literature. • Gestational age specific probabilities • Seasonal pattern of hospitalization • Efficacy of palivizumab adapted from IMpact study. • Costs: year 2002 dollars • Costs include: • Hospital costs • Cost of pulmonary clinic visits for Synagis injections • Emergency room visit cost • Drug costs • Cost of hours missed from work by parents for visits and hospitalization
Increased risk of asthma varies with chronologic age. Duration for increased asthma risk: 10 years Includes quality of life adjustment for asthma. Incorporates national estimates of annual asthma cost Future benefits and costs discounted at 3% Models with Asthma
Incremental Cost-Effectiveness Ratio • Incremental cost-effectiveness ratio (ICER): Cost1 – Cost2 = QALY1 – QALY2 Cost (Synagis) – Cost (No Synagis) QALY (Synagis) – QALY (No Synagis) • Current suggested “standards” for ICER: – Accepted zone : $200,000 – Not generally accepted zone: > $200,000 / QALY
Why is the ICER so high? • Substantial difference in costs, even without drug wastage • Very small difference in QALYs: • No proven mortality benefit • No proven long-term quality of life improvement • Change in quality of life due to asthma is small: .03 • Treating many infants at low risk for hospitalization
Improving the Recommendation’s Cost Effectiveness • Simulations modifying the AAP guidelines • Assume no drug wastage • Restrict to 1st RSV season • Younger age cutoffs (Discharged Sept. through March) • Restrict to infants born 27 weeks GA or less if discharged before RSV season; up to 30 weeks GA if discharged during RSV season
ICER by GA with New Recommendation $280,083 $216,830 $171,224 $103,053
Conclusion • In our model for premature infants without CLD, incremental Cost / QALY: • Was high for all gestational ages; Many ICER were over $1 million. • Large amount of variation across months. • Simulations identified more cost-effective options. • Pursue strategies to minimize drug wastage. • AAP guidelines could be revisited to make them more cost effective.
Limitations • Some costs were based on local estimates. • May have underestimated cost from family members missing work due to infant hospitalized with RSV. • Unclear whether causal relationship between severe RSV infection and asthma and other long-term health consequences; need for additional research. • Decrease in quality of life due to asthma based on adults.
Department of Pediatrics, Division of Neonatology/Infectious Disease Dr. Nahed El Hassan Dr. Timothy Stevens Dr. Caroline Hall Department of Community and Preventive Medicine Dr. Andrew Dick University of Rochester Collaborators