Clinical features of asthma with connective tissue diseases.

BACKGROUND

The clinical features of asthma with connective tissue diseases (CTDs) are not well-known. This study therefore aimed to investigate the clinical characteristics of asthma with CTDs.

METHODS

We retrospectively examined the records of adults (≥18 years old) with asthma followed up between January 2010 and December 2019. We then compared the clinical features of asthma with and without CTDs.

RESULTS

Among 568 subjects with asthma, 42 subjects (7.4%) had CTDs. The most frequent concomitant CTD was rheumatoid arthritis (n = 23, 54.8%), followed by systemic lupus erythematosus (n = 6, 14.3%). The proportion of women (with vs. without CTDs, 85.7% vs. 56.5%, p < 0.001) and Global Initiative for Asthma step were higher (Step 4 or 5, with vs. without CTDs, 81.0% vs. 62.0%, p = 0.01) in asthma with CTDs, whereas frequency of allergic rhinitis was higher in asthma without CTDs (with vs. without CTDs, 7.1% vs. 26.1%, p = 0.005). Eosinophil ratio (with vs. without CTDs, 2.1% vs. 3.5%, p = 0.009) and total immunoglobulin E level (with vs. without CTDs, 43 IU/mL vs. 237 IU/mL, p = 0.002) were lower in asthma with CTDs. In terms of lung function, percentage predicted forced vital capacity (with vs. without CTDs, 86.7% vs. 99.7%, p = 0.008) and percentage predicted forced expiratory volume in 1 s (%FEV1) (with vs. without CTDs, 77.2% vs. 88.4%, p = 0.02) were all lower in asthma with CTDs. With multivariable analysis, CTDs (odds ratio [OR] 2.8, 95%CI 1.3-6.0; p = 0.008), chronic obstructive pulmonary disease (OR 3.8, 95%CI 2.1-6.7; p < 0.001) and asthma onset at <20 years old (OR 1.8, 95%CI 1.1-3.2; p = 0.03) were associated with low FEV1 (defined as %FEV1 < 80%) in asthma.

CONCLUSIONS

Asthma with CTDs was related to lower lung function and low-T2 inflammation asthma.