Seasonal variations and social disparities in asthma hospitalizations and outcomes

Exposure to asthma exacerbating triggers may be dependent on the season and an individual's social factors and subsequent means to avoid triggers. We assessed for seasonal variations and differential outcomes based on race and income in admissions for asthma in a United States nationwide assessment.

This retrospective study assessed adult hospitalizations for asthma 2016-2019 using the National Inpatient Sample. Hospitalizations were categorized by season: winter (December-February), spring (March-May), summer (June-August), fall (September-November). Multivariable linear and logistic regression were used to assess associations between season, race, income quartile (determined by the median income within a patient's ZIP code), and outcomes.

The study included 423,140 admissions with a mean age of 51 years, and 73% of the cohort being female and 56% non-white. Admissions peaked during winter (124, 145) and were lowest in summer (80,525). Intubation rates were increased in summer compared to winter (2.73 vs 1.93%, aOR = 1.19, 95% CI: 1.04-1.37) as were rates of noninvasive positive pressure ventilation (NIPPV) (7.92 vs 7.06%, aOR = 1.08, 95% CI: 1.00-1.17). Compared to white patients, intubation (2.53 vs 1.87%, absolute difference 0.66%, aOR = 1.14, 95% CI: 1.02-1.29) and NIPPV (9.95 vs 5.45%, absolute difference 4.5%, aOR = 1.69, 95% CI: 1.57-1.82) were increased in Black patients. No significant associations between income and clinical outcomes were found.

Asthma admission peak during winter, while summer admissions and non-white race are associated with higher rates of NIPPV and intubation. Public health initiatives and strategically timed outpatient visits could combat seasonal variation and social disparities in asthma outcomes.