A Retrospective Cohort Study of the Incidence, Health Care Resource Utilization and Costs of International Classification of Diseases, Clinical Modification, 9th Revision Diagnosed Influenza and Related Complications in US Children.

BACKGROUND

There is a paucity of data on the clinical and economic impact of seasonal influenza in children. This study estimated the incidence of diagnosed influenza and related complications and associated health care resource utilization and costs in US children.

METHODS

Children ≥6 months and <18 years old diagnosed with influenza using International Classification of Diseases, Clinical Modification, 9th revision codes and enrolled in a health plan during at least one influenza season between 2010 and 2014 were matched to similar patients without diagnosed influenza (GSK study identifier: HO-15-15728). Outcomes included incidence of influenza and complications, health care resource utilization frequency and health care costs during 21 days of follow-up. Adjusted costs were estimated using generalized linear models.

RESULTS

Incidence (per 1000) of influenza was 20.3 (commercially insured) and 32.6 (Medicaid), with the highest incidence among 6-35 months old (Commercial: 26.8; Medicaid: 47.9). Approximately 12%-17% of influenza patients experienced complications, with the 6-35 months group having the highest percentage (25%-30%). The 6-35-month-old influenza patients with complications had the highest proportion with hospitalizations (5%-6%) and emergency room visits (Commercial: 19%; Medicaid: 36%). Influenza patients with (vs. without) complications had greater adjusted mean influenza-specific costs (Commercial: $1161 vs. $337; Medicaid: $1199 vs. $354; P<0.05), and influenza cases (vs. controls) had greater adjusted mean all-cause costs (Commercial: $688 vs. $470; Medicaid: $818 vs. $453; P < 0.05).

CONCLUSIONS

Pediatric patients with influenza incurred higher health care costs compared with matched controls, and influenza-specific costs were greater among those with complications.