Impact of landscape fire smoke exposure on patients with Asthma with or without laryngeal hypersensitivity.

Abstract

Individuals with asthma experienced severe and prolonged symptoms following the Australian 2019-2020 landscape fire period. Many of these symptoms, such as throat irritation, are referrable to the upper airway suggesting that laryngeal hypersensitivity contributes to persistent symptoms following smoke exposure. The study examined the relationship between laryngeal hypersensitivity and symptoms, asthma control and health impact in individuals exposed to landscape fire smoke. The study was a cross sectional survey of 240 participants in asthma registries who were exposed to smoke during the 2019-2020 Australian fire period. The survey, completed between March and May 2020, included questions about symptoms, asthma control and healthcare utilisation, as well as the Laryngeal Hypersensitivity Questionnaire. Daily PM2.5 concentration levels were measured over the 152 day study period. The 49 (20%) participants with laryngeal hypersensitivity had significantly more asthma symptoms (96% versus 79%, p=0.003), cough (78% versus 22%, p<0.001) and throat irritation (71% versus 38%, p<0.001), during the fire period than those without laryngeal hypersensitivity. Participants with laryngeal hypersensitivity had greater healthcare utilisation (p=<0.02), more time off work (p=0.004), and reduced capacity to participate in usual activities, (p<0.001) during the fire period, and poorer asthma control during the follow up period, (p=0.001). Laryngeal hypersensitivity is associated with persistent symptoms, reports of lower asthma control and increased healthcare utilisation in adults with asthma who were exposed to landscape fire smoke. Management of laryngeal hypersensitivity before, during or immediately after landscape fire smoke exposure might reduce symptom burden and health impact.