McLaurin et al: Increased RSV Hospitalizations in the 2014-2015 Season vs Previous Seasons1,2

A recent study by McLaurin et al examined RSV hospitalizations in preterm and full-term infants. RSV hospitalizations in the 2014-2015 RSV season were compared with the 2013-2014 season and the 2010-2014 seasons combined. Hospitalization rates in preterm infants were also compared with full-term infants.*

*Study Limitations: Infants born were identified through the presence of ICD-9-CM diagnoses, procedures, and medication codes, thus misclassifications may have occurred. Immunoprophylaxis administered in the hospital setting could not be identified.

Study Design

Data Source

MarketScan Commercial Claims AND Multistate Medicaid databases

Patient Selection Criteria

Infants born between July 1, 2009, and June 30, 2015

Included

  • Preterm infants born <37 weeks gestational age (wGA)
  • Full-term infants without health problems

Commercially insured, n=1.0 million infants born

Medicaid, n=1.2 million infants born

Excluded

  • Preterm and full-term infants with CLDP, CHD, or other special conditions: cystic fibrosis immunodeficiency congenital anomalies of respiratory system neuromuscular disease organ transplants other neuromuscular, immunological or genetic conditions

Outcomes Evaluated

  • RSV hospitalizations that occurred ≥2 days after birth hospitalization discharge were examined using the following ICD-9-CM codes:

RSV infection (079.6)

RSV bronchiolitis (466.11)

RSV pneumonia (480.1)

Study Limitations: Infants born were identified through the presence of ICD-9-CM diagnoses, procedures, and medication codes, thus misclassifications may have occurred. Immunoprophylaxis administered in the hospital setting could not be identified.

Commercially Insured Infants

Statistically significant increases were seen in Commercially Insured preterm infants 29-34 wGA and <3 months of age in the 2014-2015 season vs 2013-2014 season2

   
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Graph showing number of RSV-related hospitalizations among commercially-insured infants by gestational age and RSV season (2013-2014 vs. 2014-2015). 

Compared with the previous 4 RSV seasons, statistically significant increases were also seen among commercially insured preterm infants 29-34 wGA and <3 months of age during the 2014-2015 season1

   
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Graph showing number of RSV-related hospitalizations among commercially-insured infants by gestational age and RSV season (2010-2014 vs 2014-2015). 

Medicaid Insured Infants

Statistically significant increases were seen in Medicaid preterm infants 29-34 wGA and <3 months of age in the 2014-2015 season vs 2013-2014 season2

   
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Graph showing number of RSV-related hospitalizations among Medicaid-insured infants by gestational age and RSV season (2013-2014 vs. 2014-2015). 

Compared with the previous 4 RSV seasons, statistically significant increases were also seen among commercially insured preterm infants 29-34 wGA and <3 months of age during the 2014-2015 season1

   
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Graph showing number of RSV-related hospitalizations among Medicaid-insured infants by gestational age and RSV season (2010-2014 vs. 2014-2015). 

Summary

McLaurin et al Conclusions:

  • When comparing the 2014-2015 and 2013-2014 RSV seasons, rates were highest among infants 29-34 wGA and <3 months CA
  • ~3x greater in commercially insured infants
  • ~1.5x greater in Medicaid patients
  • There were no statistically significant differences in RSV-related hospitalization rates between the 2 seasons among infants 29-34 wGA and 6-12 months CA
  • RSV hospitalization rates were higher overall in the 2014-2015 RSV season compared with the previous 4 RSV seasons and were also highest among preterm infants with earlier GA and younger CA
  • When comparing 2014-2015 with the previous 4 seasons, despite decreases in the RSV hospitalization rates in full-term infants, rates were increased among preterm infants 29-34 wGA and <3 months CA
  • ~2x greater in commercially insured infants
  • ~1.5x greater in Medicaid patients
  • There were no statistically significant differences in RSV-related hospitalization rates when compared to the previous 4 seasons among infants 29-34 wGA and 6-12 months CA

References

  1. McLaurin K, Pavilack M, Krilov L, et al. [poster #123892]. Presented at: Academy of Managed Care Pharmacy Nexus, National Harbor, MD, October 3-6, 2016.
  2. Data on file, 3336710, AstraZeneca Pharmaceuticals LP.

RSV=respiratory syncytial virus; CLDP=chronic lung disease of prematurity; CHD=congenital heart disease