High-Dose vs. Standard-Dose Influenza Vaccine in Older Patients With Hypertension: A Post Hoc Analysis of DANFLU-1.
Langhoff AF., Johansen ND., Modin D., Janstrup KH., Bartholdy KV., Espersen C., Nealon J., Samson S., Loiacono MM., Harris R., Larsen CS., Jensen AMR., Landler NE., Claggett BL., Solomon SD., Landray MJ., Gislason GH., Køber L., Sivapalan P., Jensen JUS., Biering-Sørensen T.
Patients with hypertension (HTN) face an increased risk of complications and mortality from influenza; a risk that may be modified by influenza vaccination. There is limited evidence on the effectiveness of high-dose (HD-IIV) compared with standard-dose (SD-IIV) inactivated influenza vaccines in hypertensive individuals. This study, a post hoc analysis of DANFLU-1, a pragmatic, and open-label, individually randomized trial of HD-IIV vs. SD-IIV conducted during the 2021-2022 influenza season among participants aged 65-79 years. Prespecified outcomes in DANFLU-1 included hospitalization for influenza or pneumonia, cardiovascular, cardiorespiratory, and respiratory hospitalizations, all-cause hospitalization, and all-cause mortality. Outcomes were analyzed as both time-to-first and recurrent events. DANFLU-1 randomized 12 477 participants randomized to HD-IIV or SD-IIV, of these 6469 (51.9%) had a history of HTN. HD-IIV was associated with lower hazards for hospitalizations for pneumonia or influenza, respiratory disease, and all-cause mortality compared with SD-IIV and these associations were consistent regardless of HTN status (pinteraction = 0.09, = 0.09, and = 0.59, respectively). HD-IIV was associated with lower incidence rates of recurrent hospitalizations for pneumonia or influenza and all-cause hospitalizations compared with SD-IIV, irrespective of HTN status (pinteraction = 0.09 and = 0.75, respectively). There was evidence of potential effect modification of HD-IIV vs. SD-IIV in relation to recurrent respiratory hospitalizations, where the relative effect may be greater among those without vs. with HTN (pinteraction = 0.04). In conclusion, this post hoc analysis of a large-scale pragmatic trial, HD-IIV was associated with lower risk of clinical outcomes, including hospitalizations for pneumonia or influenza, all-cause mortality, and all-cause hospitalizations irrespective of the presence of HTN. Trial Registration: ClinicalTrials.gov identifier: NCT05048589.