Asthma manifestations, health-related factors, and sickness absence: A national register-based study.

Background: There is limited evidence on how asthma manifestations and health-related factors influence sickness absence among patients with asthma. Objective: We sought to investigate the impact of asthma control, lung function, allergy, and health-related factors (overweight/obesity, physical activity, and smoking) on sickness absence among adult patients with asthma. A secondary aim was to estimate productivity losses related to sickness absence for uncontrolled asthma. Methods: The study included 69,548 patients with asthma 18 to 65 years old registered in the Swedish National Airway Register during 2021-2022. Data on asthma manifestations and health-related factors were obtained from the most recent health care visit. Sickness absence (>14 days) during 2022 was obtained from Statistics Sweden. Analyses were performed with logistic regression models using multiple imputations. Productivity losses were calculated using the human capital approach. Results: Overall, 17.4% of patients had any sickness absence. Uncontrolled asthma was associated with increased odds of sickness absence compared with controlled asthma (adjusted odds ratio, 1.46; 95% CI, 1.37-1.56), whereas no association was observed for low lung function or allergy. Overweight, obesity, low physical activity, and smoking were independently associated with sickness absence. Individuals with uncontrolled asthma had more days of sickness absence (19.3 vs 11.2, Conclusions: Uncontrolled asthma and adverse health-related factors were independently associated with sickness absence and related productivity losses among working-age patients with asthma. Improving asthma control and modifiable health-related factors may reduce sickness absence and societal costs.