Bacterial infections were found in 21.1% of patients with asthma exacerbations (AEs), and Chlamydia pneumoniae was associated with longer use of corticosteroids in patients with AEs without obesity. These were among study findings published in BMC Pulmonary Medicine.
Researchers compared clinical characteristics and pathogens associated with AEs in patients with and without obesity.
Adult patients with AEs from 24 secondary or tertiary medical institutes in the Republic of Korea were screened between January 2015 and December 2018. Eligible participants were diagnosed with asthma at least 6 months before the occurrence of an AE. Viruses and bacteria that were confirmed with microbiologic assessment at AE diagnosis were evaluated.
The analysis included 407 patients — 171 (42.0%) with obesity and 236 (58.0%) without. Their mean (SD) age was 66.4 (17.4) years, and 69.3% were women. The group with obesity had a significantly higher proportion of individuals who had never smoked vs the group without obesity (82.5% vs 73.9%, P =.026).
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Although the reason for the higher incidence of C infection in nonobese patients is unclear, identification of C pneumoniae as an acute infectious pathogen as well as colonization might be important in uncontrolled asthma or AE.
Of the cohort, 27.8% of patients were not receiving maintenance treatment at the time of AE. No significant difference occurred in asthma control level between the 2 groups, although more patients with vs without obesity had uncontrolled asthma (41.4% vs 30.5%, P =.077).
Bacterial infection was identified in 21.1% of patients with AE. Overall, viral or bacterial infection was identified in 205 (50.4%) patients: 119 patients had viral infection only, 49 had bacterial only, and 37 had both infections. Influenza virus was the most frequently isolated virus (n=67), followed by human rhinovirus (n=37) and respiratory syncytial virus (RSV; n=17). No significant difference occurred in the incidence of viral infection between the 2 groups.
Streptococcus pneumoniae (n=25), Pseudomonas aeruginosa (n=17), and C pneumoniae (n=10) were the dominantly isolated bacteria. The patients with obesity had a lower incidence of C pneumoniae infection than patients without obesity (1.0% vs 7.6%, P =.024).
Systemic corticosteroids were used by 341 of 379 patients (90.0%) for treatment of AE. Patients with vs without obesity were significantly more likely to receive systemic corticosteroids (92.0% vs 88.4%, P =.048) and had a tendency for a greater duration of corticosteroid use (12.8 [12.6] vs 10.4 [10.5] days, P =.066).
Among those with obesity, no significant differences were found in treatment outcomes based on viral or bacterial infection. Among those without vs with obesity, bacterial infection was associated with a greater duration of corticosteroid use (13.6 [19.8] vs 9.7 [6.7] days, P =.049), and C pneumoniae infection was associated with a longer AE duration (22.7 [15.9] vs 9.9 [7.5] days, P <.001) and longer corticosteroid use (25.0 [39.2] vs 9.8 [6.7] days, P <.001).
Limitations include the relatively small number of participants. Additionally, patients with AE were not compared with those with stable asthma or with healthy individuals, it was not possible to assess the effects of the susceptibility test results on treatment outcomes, and researchers did not correct for differences among institutions.
“Although the reason for the higher incidence of C infection in nonobese patients is unclear, identification of C pneumoniae as an acute infectious pathogen as well as colonization might be important in uncontrolled asthma or AE,” the study authors stated.
