Association between Asthma Control and Health-Related Quality of Life in Severe Asthma: A Cross-Sectional Study from KoSAR

Background Severe asthma (SA) poses a significant burden on patients’ health-related quality of life (HRQoL). This study aimed to quantify HRQoL burden and identify clinical determinants associated with HRQoL impairment in patients with SA. Methods Cross-sectional data were collected from 701 patients (592 with SA, 109 with non-severe asthma [NSA]) in the Korean Severe Asthma Registry (KoSAR). HRQoL was measured using the EQ-5D-5L and Severe Asthma Questionnaire (SAQ). Asthma control status was assessed with the Asthma Control Test (ACT) scores. Multivariable and ordinal logistic regression analyses were conducted to factors associated with HRQoL. Results Patients with SA had lower EQ-5D-5L scores than those with NSA (SA: 0.83 versus NSA: 0.87, p<0.001). Among patients with SA, recent rescue medication use, reduced lung function, and uncontrolled symptoms were associated with impaired HRQoL. Uncontrolled SA was associated with greater impairments than controlled SA (uncontrolled: 0.75 versus controlled 0.85, p<0.001). Uncontrolled SA was associated with higher odds of worse health states across all five domains, with greatest impairments in usual activities dimension. The EQ-5D-5L scores decreased in proportion to the level of asthma control. ACT scores strongly correlated with both EQ-5D-5L ( r =0.608, p<0.001) and SAQ ( r =0.680, p<0.001). Amongst ACT items, “daily functioning” was the strongest determinant of HRQoL. Conclusion Uncontrolled asthma, particularly its impact on daily functioning, was associated with HRQoL impairment in patients with SA. Enhancing asthma control may significantly reduce the disease burden and improve HRQoL in SA.