[Relationship between comorbidity and asthma control]

The coexistence of potentially aggravating processes is common in asthmatics, particularly in patients with difficult control. The primary aim of this study is to ascertain whether comorbidity id more common in uncontrolled patients. As a secondary aim, we propose to evaluate the correlation between the asthma control test (ACT) and the fraction of exhaled nitric oxide (FENO).

A prospective, observational study comparing the function and clinical picture of two groups of asthmatics: controlled (ACT≥20) and uncontrolled (ACT<20). They were all assessed for, smoking, rhinosinusitis, obesity, anxiety, depression, vocal cord dysfunction, gastro-oesophageal reflux (GORD), allergic bronchopulmonary aspergillosis (ABPA), COPD and nasal polyps.

A total of 50 patients with controlled asthma and 102 with suboptimal control were included. The patients with an ACT≥20 had better lung function, less variation in PEF, less bronchial hyper-reactivity and lower FENO values. Comorbidities were found in 95% of the controlled asthmatics and in 97% of the uncontrolled. Only the presence of nasal polyps, GORD and ABPA was more frequent in the uncontrolled group. However, the simultaneous presence of 3 or more comorbidity factors was significantly more frequent in patients with sub-optimal control (P=0.01). There was no significant correlation between the FENO and the ACT values (rho=-0.08; P=0.32).

Aggravating comorbidities are more common in patients with sub-optimal control. There was no correlation between the FENO and the ACT values.