(111) Inhaled corticosteroid use associated with severity of COVID-19 diagnosis among patients with asthma, a cohort study

Background: Early findings suggest a lower asthma prevalence among COVID-19 patients. A few studies investigated the association between inhaled corticosteroid (ICS) consumption and the severity of COVID-19 diagnosis among asthma patients.

Objectives: To determine the association between ICS consumption and severity of COVID-19 diagnosis among asthma patients.

Methods: This was a register-based cohort study that used the SCIFI-PEARL cohort database, containing linked data from Swedish national health registers, dispensed prescription drugs, and sociodemographic data. We selected all adults (≥20 years old) at their first diagnosis of asthma in Stockholm and Västra Götaland regions in Sweden between 2015.01.01-2020.02.28 based on ICD code J45 and J46 as a primary or secondary diagnosis from primary or secondary care. Exposure to ICS was defined as a first filled prescription (ATC codes R03AK, R03BA) at any time within 1 month before or any time after the first asthma diagnosis, until the end of the study 30 Sept 2022. Asthma patients without ICS were considered unexposed. We matched exposed- and unexposed patients individually 1:1 based on sex, age, and year of identified first asthma diagnosis. The index date in both groups was the ICS dispensation date. We defined 4 separate COVID-19 outcomes: PCR test-positive, hospitalization, ICU admission, or death due to COVID-19. The outcomes were assessed in a time window one week before to four weeks after the PCR positive test and each individual was classified by the most severe outcome assessed in this window. We used COX regression analysis with follow-up from the index date to 30 Sept 2023. Results are presented as adjusted HRs (aHR) and 95% confidence intervals (95%CI). Covariates were: sex, education at the pandemic, marital status at the pandemic, employment status at the pandemic, and birth location.

Results: Among 15,498 matched asthma patients, 4323 had a COVID-19 outcome: 88.7% had only a positive PCR test, 8.9% were hospitalized, 0.4% were admitted to the ICU, and 2.0% died. ICS use increased the risk of hospitalization (HR 1.23, 95% CI 1.02-1.48), with no increased risk for ICU admission or death. Older age strongly raised the risk of all 3 severe outcomes. Females had lower risks for hospitalization (HR 0.63, 95% CI 0.52-0.78), ICU admission (HR 0.34, 95% CI 0.16-0.75), and death (HR 0.50, 95% CI 0.32-0.78) compared to males. Unemployment was associated with higher risks of hospitalization (HR 2.26, 95% CI 1.71-3.00) and death (HR 3.87, 95% CI 1.46-10.26).

Conclusions: ICS use in asthma patients moderately increased hospitalization risk, with no impact on other outcomes. Age and unemployment also contributed to the risk of severe outcomes. Larger studies considering more confounders are suggested.