Adverse respiratory outcomes amongst patients with resolved asthma: matched retrospective cohort study

Abstract

Background: Patients with asthma may have symptom remission leading to a primary care code of resolved asthma. Little is known about subsequent rates of exacerbations and respiratory tract infections (RTI). Aim: To assess the risk of adverse respiratory outcomes for people with resolved asthma compared to those with active asthma and without asthma. Design and setting: This was a retrospective cohort study of patients aged >5 years, registered with a General Practice in England contributing data to the Clinical Practice Research Datalink between January 2010 and December 2019. Method: Patients with resolved asthma were matched to non-asthma controls and active asthma controls on age, sex, and practice. We used negative binomial regression to estimate incidence rate ratios (IRR) with 95% confidence intervals (CI) for asthma exacerbations, RTIs, influenza/pneumonia, and antibiotic prescriptions. Results: Cohorts included 16,023 patients (54.4% female, mean age 37 years). Compared to the active asthma cohort, the resolved cohort had fewer hospital admissions (adjusted IRR 0.29, 95% CI (0.27-0.32) and General Practice consultations (adjusted IRR 0.05, 95% CI (0.04-0.07) for asthma exacerbations. The resolved and non-asthma cohorts had similar rates of hospital admissions for RTI or influenza/pneumonia. However, the resolved cohort had significantly greater incidence of General Practice consultations for RTI (adjusted IRR 2.34, 95% CI 2.08-2.64) and antibiotic prescriptions (adjusted IRR 1.37, 95% CI 1.30-1.44). Conclusion: Patients with resolved asthma had greater risk of General Practice RTI and antibiotic prescription than the general population and may benefit from defined strategies for reassessing symptoms and reinitiating asthma therapy.