Recurrent respiratory infections and allergy hallmarks at-risk progression to severe asthma

Background: Allergic asthma (AA) is associated with an increased risk of infections requiring antibiotics and allergen immunotherapy appears to prevent asthma progression. The association between allergy, recurrent respiratory infections (RRI) and the risk of developing severe asthma (SA) remains unclear.

Aim: To assess whether RRI and allergy are associated with a higher risk of subsequent development of SA.

Methods: A group of patients with non-SA with and without allergy was selected from the prospective nationwide population register-based Swedish data from NORdic Dataset for aSThmA Research (NORDSTAR) collaboration platform. Selection criteria was based on the redemption of asthma- and anti-allergic medications. RRI was assessed for a 2-year exposure period and the proportion of patients developing SA was assessed over a 3-year outcome period (Figure 1).

Results: 401,643 patients fulfilled inclusion criteria (74 215 patients with AA and 327,428 patients with non-AA). RRI were associated with an increased risk of development of SA across both non-AA and AA, but with the highest risk observed in the latter group; OR = 1.51 (1.12, 1.99) and RR = 3.47 (2.49, 4.83) respectively.

Conclusion: In mild/moderate asthma, RRI are associated with an increased risk of subsequent progression into SA, with the highest risk among moderately-severly allergic individuals, representing hallmarks of patients at-risk developing SA.