Respiratory syncytial virus (RSV) is the predominant cause of lower respiratory tract infections (LRTI) in infants and young children.1 , 2 RSV-related hospitalizations (RSVH) are associated with a major healthcare burden.3 Of approximately 2.8 million new episodes of RSV-related infections reported in children less than 5 years of age in high-income countries in 2015, at least 383,000 children required hospital admission.4 RSV is also estimated to underlie up to 75% of all childhood cases of bronchiolitis and up to 40% of all childhood pneumonias.5 Furthermore, about 200 infant deaths are reported to be caused by RSV-related lower respiratory tract infection annually in the United States.6 The risk of RSV and burden of RSVH is greater in premature infants, defined as less than 36 completed weeks of gestational age (wGA), due to incomplete pulmonary development, immature immunologic responses and lower levels of maternally transmitted, RSV-specific antibodies, compared with infants born at term.7–10 It has previously been shown that preterm infants hospitalized for RSV had significantly higher intensive care unit (ICU) stays and higher intubation rates compared with term infants.11
In Canada, passive immunoprophylaxis with palivizumab, a humanized monoclonal antibody, has been approved for high risk infants including those with a history of prematurity (≤35 wGA) since 2002. Palivizumab significantly reduces the incidence of RSVH in infants born at ≤35 wGA, and prophylaxis was associated with shorter length of hospital stay, fewer days with oxygen and lower incidence of ICU admission.12 In addition, palivizumab was shown to be cost -effective in the 32–35 wGA group in Canadian settings.13 However, in 2015, the Canadian Pediatric Society modified their position statement to limit the use of palivizumab for prophylaxis in infants <30 weeks (29 completed wGA), unless other comorbidities were also present.14 Starting in the 2015–2016 RSV season, the Quebec Ministry of Health (Ministère de la Santé et des Services sociaux) also revised their eligibility criteria for palivizumab; late preterm Quebec infants born 33–35 wGA without qualifying comorbidities were no longer eligible to receive palivizumab for prophylaxis. To study the impact of that change, we evaluated the cost of withdrawing passive RSV immunoprophylaxis in infants born at 33–35 wGA in Quebec using a cost -comparison analysis.
METHODS
Model Design
A cost -comparison model was developed in Microsoft Excel 2013 (Microsoft, Redmond) to estimate the economic impact of withdrawing passive immunoprophylaxis for RSV and applied to a cohort of infants born at 33–35 wGA <6 months of age in Quebec. Guidelines for cost -comparison analysis from the National Institute for Health and Care Excellence were followed.15 This analysis was performed from both the payer perspective (Quebec Ministry of Health) and the societal perspective and included all direct and indirect costs associated with RSV/LRTI hospitalization. The time horizon in the clinical visits and resource use before hospitalization was 72 hours before hospitalization and 30 days afterward to account for discharge medications. To correct for inflation, all costs were converted to 2018 Canadian Dollars using the inflation rate of 2.16% provided by Bank of Canada.16 Total costs and average costs per infant rounded to the nearest dollar are presented. A post hoc analysis was also conducted to assess whether costs of prophylaxis offset the cost of RSV/LRTI hospitalization in late preterm infants.
Input Parameters
Data from the RSV-Quebec study (Tables 1 and 2 ) were used to evaluate the cost of RSV/LRTI hospitalization following withdrawal of immunoprophylaxis over the time horizon of the analysis. RSV-Quebec was a multicenter retrospective cohort study involving 20 hospitals and 5 hospital-based birthing centers across different geographical regions of Quebec.17 , 18 All otherwise healthy infants born at 33–35 wGA and <6 months at the start of or born during the RSV season with RSV/LRTI hospitalizations [presumed or confirmed RSV/LRTI) during 4 seasons (2013–2014 (season 1), 2014–2015 (season 2), 2015–2016 (season 3) and 2016–2017 (season 4)] were included. RSV/LRTI hospitalization was defined as laboratory-confirmed RSV-associated hospitalization or LRTI hospitalization when RSV was circulating in the community and for which no RSV testing was performed and no other etiology found. Eligible participants were identified through the hospital discharge abstract databases using LRTI- and RSV-specific International Classification of Diseases-9 or -10 discharge diagnosis codes for nonspecific bronchiolitis, bronchitis or pneumonia and for RSV bronchiolitis, RSV acute bronchitis, RSV pneumonia, RSV apnea or RSV as a cause of disease classified elsewhere. In addition, for each eligible preterm infant, 2 term infants (≥37 wGA and <6 months at the start of or born during the RSV season) in seasons 3/4 matched for age, gender and month of RSV/LRTI hospitalization were identified for inclusion. This cohort was included to provide a benchmark. Parents/legal guardians of infants hospitalized due to RSV/LRTI in seasons 3/4 were approached to complete questionnaires assessing healthcare resource utilization (HCRU), work productivity and activity impairment during the RSV/LRTI hospitalization of their child to assess burden of illness. Those who agreed to participate gave written consent before completing the questionnaires.
TABLE 1.: Clinical Inputs Used to Model Direct Costs of Withdrawing Immunoprophylaxis in Infants Born at 33–35 Weeks Gestational Age
TABLE 2.: Clinical Inputs Used to Model Indirect Costs of Withdrawing Immunoprophylaxis in Infants Born at 33–35 Weeks Gestational Age
The RSV-Quebec dataset included outcomes from a total of 105 preterm infants who were hospitalized for RSV/LRTI during seasons 1/2 (prerevision of guidelines), 130 preterm in seasons 3/4 (postrevision of guidelines) and 234 term infants hospitalized for RSV/LRTI in seasons 3/4. Of these patients, 97 of 105 (92.4%) tested positive for RSV in seasons 1/2, 106 of 130 (81.5%) in seasons 3/4 and 200 of 234 (85.5%) term infants.
Cost Inputs
Cost inputs were broken down into direct (hospital stay, physician billing, microbiology tests, and hospitalization discharge/medications, HCRU associated with hospitalization, prophylaxis administration) (Table, Supplemental Digital Content 1, https://links.lww.com/INF/D940 ) and indirect costs (missed work and lost productivity, HCRU associated with hospitalization and hospitalization discharge medications) (see Table, Supplemental Digital Content 1, https://links.lww.com/INF/D940 ). Direct and indirect costs were estimated based on provincial and government sources. Further information regarding unit cost sources, assumptions made for the analysis, and supporting literature13 , 17–31 is provided in Supplemental Digital Content 2, https://links.lww.com/INF/D941 .
RESULTS
Base-case Estimate
As shown in Table 3 , the observed average direct cost in preterm infants hospitalized due to RSV/LRTI in seasons 3/4 was higher at $28,465 compared with $16,232 for preterm infants in seasons 1/2. In univariate analyses, length of stay in the emergency department during hospitalization was associated with higher direct costs in seasons 3/4 (Table 1 ). Also, the proportion of infants discharged with medications in seasons 3/4 was lower compared with infants in seasons 1/2. Specifically, the proportion of infants discharged with antibiotics in seasons 3/4 was lower compared with infants in seasons 1/2 (21% vs. 32%; χ2 = 4.08, P = 0.044). As expected, indirect costs were similar between preterm infants in seasons 3/4 and those in seasons 1/2 ($742 vs. $744). This difference reflects differences in numbers of patients because indirect costs in seasons 1/2 were imputed from data collected in seasons 3/4.
TABLE 3.: Cost -Comparison Analysis (Societal Perspective)
Impact of Palivizumab
Based on the Risk Scoring Tool Validation article by Paes et al,28 which estimated that 19% of infants with 33–35 wGA would have moderate-to-high risk scores, 20 infants were projected to qualify for RSV prophylaxis in the RSV-Quebec study in seasons 1/2. The total cost of prophylaxis for those infants was $93,184 with an average cost of $4659 per infant. The additional cost of prophylaxis among hospitalized infants increased the average direct costs in seasons 1/2 to $20,892, which was still lower than direct costs in seasons 3/4.
Comparison to Term Infants
When comparing preterm infants in seasons 3/4 to term infants who were hospitalized due to RSV/LRTI during that same time period, average direct costs were higher in preterm infants compared with term infants ($28,465 vs. $9509) (Table 4 ). Determinants of direct costs were longer length of stay in the pediatric unit, higher proportion of infants hospitalized in the PICU and longer length of stay in the PICU, higher proportion of infants hospitalized in the neonatal ICU and a higher proportion of infants hospitalized in the short-stay unit. In addition, compared with term infants, a higher proportion of preterm infants required complex ventilation. Specifically, a higher proportion of preterm infants required high-frequency oscillatory ventilation compared with term infants (2% vs. 0%; χ2 = 5.45, P = 0.020). A higher proportion of preterm infants also required feeding tubes, specifically duodenal feeding tubes, (5% vs. 1%; χ2 = 5.27, P = 0.022) during hospitalization. In terms of HCRU, a higher proportion of preterm infants required clinical visits and transfers to another medical facility before hospitalization. Specifically, a higher proportion of preterm infants visited the local community health center (CLSC) compared with term infants (13% vs. 5%; χ2 = 3.94, P = 0.047). Average indirect costs associated with an RSV/LRTI hospitalization were lower in preterm infants compared with term infants ($742 vs. $782). Paternal loss of productivity (F = 6.96, P = 0.009) was the only parameter that was significantly different between groups.
TABLE 4.: Health Outcomes in the RSV-Quebec Study
Outcomes
As shown in Table 4 , there were no differences in outcomes between preterm infants in seasons 1/2 and preterm infants in seasons 3/4. While Parental Stressor scale total scores were not significantly different for both parents between preterm and term infants in seasons 3/4, fathers of preterm infants reported a significantly higher percentage of activity impairment compared with fathers of term infants.
Interpretation
Overall, preterm infants hospitalized for RSV/LRTI postrevision of guidelines incurred higher average direct costs than preterm infants hospitalized prerevision of guidelines. In addition, direct costs associated with hospitalization in preterm infants postrevision of guidelines were higher compared with term infants hospitalized in the same time period. Indirect costs were similar between preterm infants pre- and postrevision of guidelines but were slightly higher in term infants. Compared with term infants, fathers of preterm infants in seasons 3/4 reported significantly higher absenteeism from work and higher activity impairment.
Previous reports suggest that infants born at 33–35 wGA have the highest RSVH-associated resource use compared with other gestational ages.11 Lower hospitalization-related costs in seasons 1/2 before guideline revisions imply that immunoprophylaxis in infants born at 33–35 wGA may have a favorable economic impact from the payer perspective despite higher acquisition costs of palivizumab. These findings are supported by previous findings showing cost -effectiveness of palivizumab in late preterm infants based on the presence of risk factors,32–39 especially in Canada.13 , 40 Similarly, late preterm infant hospitalizations for RSV/LRTI postguideline revisions were associated with higher costs from the payer perspective compared with term infant hospitalizations. These differences were mainly due to the increased morbidity in preterm infants consistent with prior research showing a higher likelihood of being admitted to the ICU and higher frequencies of respiratory distress and feeding difficulties among other complications in late preterm infants compared with term infants.41 In addition, LRTI/RSVH of preterm infants postrevision of guidelines were associated with significantly higher caregiver burden represented by significant paternal loss of wages during hospitalization and impairment of the ability to conduct activities of daily living, compared with term infants. These findings are consistent with previous reports of paternal burden in Canadian infants hospitalized for RSV42 and further recognize the societal burden associated with RSV/LRTI.
The Quebec-RSV study provided a unique opportunity to demonstrate the economic impact of a change in guidelines that removed RSV prophylaxis for infants of 33–35 wGA. Furthermore, study findings extend the current literature by analyzing the indirect costs and caregiver burden associated with RSV/LRTI hospitalizations. However, the present study had several limitations. First, average cost of hospital stays in different wards were obtained from the, which may not be reflective of costs in Quebec. However, we have adjusted these costs by including physician billing costs based on data from McGill University Health Centre. Testing for RSV was not systematically conducted in all infants which may create a nonrandom bias; however, the study provided real-world evidence of the economic consequences of removing immunoprophylaxis in an at-risk group. The lack of consistent RSV testing also limited the assessment of RSVH as the primary outcome. However, because RSV is the leading cause of LRTI, the present study assessed RSV/LRTI as the primary outcome. Moreover, >85% of preterm and term RSV/LRTI hospitalizations had laboratory-confirmed RSV infection. Second, RSV prophylaxis of infants of 33–35 wGA in seasons 1/2 (preguideline change) was unavailable to researchers as it was generally not documented in patients’ hospitalization records, leading to a mixed group of prophylaxed and nonprophylaxed infants. The mixed group of prophylaxed and nonprophylaxed infants in seasons 1/2 means that the incidence of RSV/LRTI hospitalization in prophylaxed infants only is unknown, which may also subsequently affect the results of the cost -comparison analysis. However, it does represent total costs of hospitalization in that patient population, consistent with the perspective. The Health Resource Utilization Questionnaire was not completed in seasons 1/2. Future studies should extend the present findings by assessing the economic impact of long-term consequences associated with withdrawal of immunoprophylaxis in infants born at 33–35 wGA. For example, severe RSV/LRTI in infancy has been associated with long-term respiratory problems, including recurrent wheezing, asthma and possibly allergic sensitization later in life,43 which may contribute to increased healthcare costs later in childhood. Because palivizumab has been shown to be effective in reducing recurrent wheezing following RSVH,43 immunoprophylaxis may have a long-term advantage that should be considered in economic models.
Late preterm infants constitute a group at greater risk of RSVH compared with full-term infants, resulting in substantial morbidity following hospital admission. As simulated in a model by McLaurin et al,44 the annual number of RSVH in late preterm infants is expected to increase following the change in guidelines based on moderate rates. This increase in RSVH would lead to an increase in hospitalization days, ICU admissions and mechanical ventilation events.44 This cost -comparison analysis showed that the time period before guideline changes held a cost advantage for hospitalizations due to RSV/LRTI, compared with the time period postguideline change from the payer perspective in infants born at 33–35 wGA. Direct costs were also higher in 33–35 wGA infants hospitalized for RSV/LRTI postrevision of guidelines compared with term infants. These findings suggest that immunoprophylaxis may be cost -saving in this at-risk group and may reduce burden of illness.
REFERENCES
1. Collins CL, Pollard AJRespiratory syncytial virus infections in children and adults. J Infect. 2002;45:10–17.
2. Glezen WP, Taber LH, Frank AL, et al.Risk of primary infection and reinfection with respiratory syncytial virus. Am J Dis Child. 1986;140:543–546.
3. Hasegawa K, Tsugawa Y, Brown DF, et al.Trends in bronchiolitis hospitalizations in the United States, 2000-2009. Pediatrics. 2013;132:28–36.
4. Shi T, McAllister DA, O’Brien KL, et alRSV Global Epidemiology Network. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in young children in 2015: a systematic review and modelling study. Lancet. 2017;390:946–958.
5. Hall CB, Hall WJBronchiolitis. Principles and Practice of Infectious Disease. 1995.4 ed. New York, NY: Churchill Livingston;
6. Thompson WW, Shay DK, Weintraub E, et al.Mortality associated with influenza and respiratory syncytial virus in the United States. JAMA. 2003;289:179–186.
7. Haerskjold A, Kristensen K, Kamper-Jørgensen M, et al.Risk factors for hospitalization for respiratory syncytial virus infection: a population-based cohort study of Danish children. Pediatr Infect Dis J. 2016;35:61–65.
8. Cilla G, Sarasua A, Montes M, et al.Risk factors for hospitalization due to respiratory syncytial virus infection among infants in the Basque Country, Spain. Epidemiol Infect. 2006;134:506–513.
9. Friedrich L, Pitrez PM, Stein RT, et al.Growth rate of lung function in healthy preterm infants. Am J Respir Crit Care Med. 2007;176:1269–1273.
10. Yeung CY, Hobbs JRSerum-gamma-G-globulin levels in normal premature, post-mature, and “small-for-dates” newborn babies. Lancet. 1968;1:1167–1170.
11. Horn SD, Smout RJEffect of prematurity on respiratory syncytial virus hospital resource use and outcomes. J Pediatr. 2003;143(5 suppl):S133–S141.
12. Palivizumab, a humanized respiratory syncytial virus monoclonal antibody, reduces hospitalization from respiratory syncytial virus infection in high-risk infants. The IMpact-RSV Study Group. Pediatrics. 1998;102(3 pt 1):531–537.
13. Lanctôt KL, Masoud ST, Paes BA, et al.The
cost -effectiveness of palivizumab for respiratory syncytial virus prophylaxis in premature infants with a gestational age of 32-35 weeks: a Canadian-based analysis. Curr Med Res Opin. 2008;24:3223–3237.
14. Robinson JL, Le Saux NCanadian Paediatric Society, Infectious Diseases and Immunization Committee. Preventing hospitalizations for respiratory syncytial virus infection. Paediatr Child Health. 2015;20:321–333.
15. NICE. User guide for the
cost comparison company evidence submission template. 2017. Available at:
https://www.nice.org.uk/process/pmg32/chapter/instructions-for-companies . Accessed December 20, 2019.
16. Bank of Canada. Inflation Calculator. 2019. Available at:
https://www.bankofcanada.ca/rates/related/inflation-calculator/ Accessed December 20, 2019.
17. Papenburg J, Defoy I, Masse E, et al.Impact of the withdrawal of palivizumab immunoprophylaxis on the incidence of respiratory syncytial virus hospitalizations among infants born at 33 to 35 weeks gestational age in the province of Quebec, Canada (RSV-QC STUDY). Am J Perinatol. 2019;36(suppl 02):S139–S148.
18. Caouette G, Papenburg J, Masse E, et al.Disease severity of hospitalizations for RSV lower respiratory tract infections among term infants and infants born 33-35 weeks gestational age in Quebec. International Conference on Clinical Neonatology (ICCN). Am J Perinatol. 2019;36(suppl 02):S139–S148.
19. Ministère de la Santé et des Services sociaux. Répertoire Québécois Et Système De Mesure Des Procédures De Biologie Médicale - Edition 2019-2020. 2019.Québec: Ministère de la Santé et des Services sociaux;
20. Statistics Canada. Table 18-10-0001-01. Monthly average retail prices for gasoline and fuel oil, by geography. Available at:
https://doi.org/10.25318/1810000101-eng . Accessed December 20, 2019.
21. Government of Quebec. Ambulance Service. Available at:
https://www.quebec.ca/en/health-system-and-services/medical-transport/ambulance-service . Accessed December 20, 2019.
22. Régie de l’assurance maladie du Québec. List of Medications. 2019. Available at:
https://www.ramq.gouv.qc.ca/SiteCollectionDocuments/liste_med/2019/liste_med_2019_03_07_en.pdf . Accessed October 23, 2019.
23. Mitchell I, Saleem M, Li A, et al.73 changes in palivizumab usage in Canada 2005-2017 (data from CARESS registry). Pediatr Child Health. 2019;24:e28–e29.
24. Smaldone A, Tsimicalis A, Stone PWMeasuring resource utilization in patient-oriented comparative effectiveness research: a psychometric study of the Resource Utilization Questionnaire. Res Theory Nurs Pract. 2011;25:80–106.
26. Salary scales and list of job titles Collective Agreement July 2016 - March 2020. Montreal: Fédération Interprofessionnelle de la santé du Québec. 2016. Available at:
http://www.fiqsante.qc.ca/wp-content/uploads/2016/10/Echelles_salariales_Web_2016-2020_ANG.pdf?download=1 . Accessed October 23, 2019.
27. Mitchell I, Paes BA, Li A, et alCARESS investigators. CARESS: the Canadian registry of palivizumab. Pediatr Infect Dis J. 2011;30:651–655.
28. Paes B, Cole M, Latchman A, et al.Predictive value of the respiratory syncytial virus risk-scoring tool in the term infant in Canada. Curr Med Res Opin. 2009;25:2191–2196.
29. Reilly MC, Zbrozek AS, Dukes EMThe validity and reproducibility of a work productivity and activity impairment instrument. Pharmacoeconomics. 1993;4:353–365.
30. Institut de la statistique Quebec. Weekly and hourly earnings of employees by sex, Montréal and all of Québec, 2014-2018. 2019. Available at:
http://www.stat.gouv.qc.ca/statistiques/profils/profil06/societe/marche_trav/indicat/tra_remuneration06_an.htm . Accessed October 23, 2019.
31. Miles MS, Brunssen SHPsychometric properties of the parental stressor scale: infant hospitalization. Adv Neonatal Care. 2003;3:189–196.
32. Bentley A, Filipovic I, Gooch K, et al.A
cost -effectiveness analysis of respiratory syncytial virus (RSV) prophylaxis in infants in the United Kingdom. Health Econ Rev. 2013;3:18.
33. Smart KA, Lanctôt KL, Paes BAThe
cost effectiveness of palivizumab: a systematic review of the evidence. J Med Econ. 2010;13:453–463.
34. Chirico G, Ravasio R, Sbarigia UCost-utility analysis of palivizumab in Italy: results from a simulation model in the prophylaxis of respiratory syncytial virus infection (RSV) among high-risk preterm infants. Ital J Pediatr. 2009;35:4.
35. Sanchez-Luna M, Burgos-Pol R, Oyagüez I, et al.
Cost -utility analysis of palivizumab for respiratory syncytial virus infection prophylaxis in preterm infants: update based on the clinical evidence in Spain. BMC Infect Dis. 2017;17:687.
36. Resch B, Sommer C, Nuijten MJ, et al.
Cost -effectiveness of palivizumab for respiratory syncytial virus infection in high-risk children, based on long-term epidemiologic data from Austria. Pediatr Infect Dis J. 2012;31:e1–e8.
37. Hampp C, Kauf TL, Saidi AS, et al.
Cost -effectiveness of respiratory syncytial virus prophylaxis in various indications. Arch Pediatr Adolesc Med. 2011;165:498–505.
38. Mahadevia PJ, Masaquel AS, Polak MJ, et al.
Cost utility of palivizumab prophylaxis among pre-term infants in the United States: a national policy perspective. J Med Econ. 2012;15:987–996.
39. Paes B, Rodgers-Gray B, Carbonell-Estrany XResch BResolving the debate on RSV prophylaxis in late preterm infants. In: The Burden of Respiratory Syncytial Virus Infection in the Young. 2019: London, UK: IntechOpen; 190–246.
40. Smart KA, Paes BA, Lanctôt KLChanging costs and the impact on RSV prophylaxis. J Med Econ. 2010;13:705–708.
41. Raju TN, Higgins RD, Stark AR, et al.Optimizing care and outcome for late-preterm (near-term) infants: a summary of the workshop sponsored by the National Institute of Child Health and Human Development. Pediatrics. 2006;118:1207–1214.
42. Mitchell I, Defoy I, Grubb EBurden of respiratory syncytial virus hospitalizations in Canada. Can Respir J. 2017;2017:4521302.
43. Simões EAF, Bont L, Manzoni P, et al.Past, present and future approaches to the prevention and treatment of respiratory syncytial virus infection in children. Infect Dis Ther. 2018;7:87–120.
44. McLaurin KK, Chatterjee A, Makari DModeling the potential impact of the 2014 American Academy of Pediatrics Respiratory Syncytial Virus Prophylaxis Guidance on Preterm Infant RSV Outcomes. Infect Dis Ther. 2015;4:503–511.