Are nighttime respiratory symptoms assessed by asthma control test affected by comorbidities?

OBJECTIVE: Nocturnal symptoms are common in the asthmatic population, reflecting an exaggerated airway narrowing overnight due to several factors; it is questioned to what extent the awakenings documented in the clinical assessment of asthma control are due to the disease itself or to comorbidities. To answer this question, we aimed to evaluate to what proportion rhinitis, gastroesophageal reflux and the likelihood of being affected by OSAS were related to poor asthma control, by means of ACT evaluation.

METHODS: Asthmatics attending the outpatient clinic were enrolled and administered the following questionnaires: ACT, Total 5 Symptom Score, GERD Impact Scale, Pittsburgh Sleep Quality Index and the Sleep Disorders Questionnaire.

RESULTS: One-hundred consecutive patients (M/F: 42/58, mean age 52 ± 15 years) were recruited. According to the ACT findings, 14 asthmatics resulted as fully controlled (FC, ACT equal to 25), 55 partially controlled (PC, 25 < ACT >19) and 31 as uncontrolled (UC, ACT <19). GERD was not associated with the ACT score neither did rhinitic symptomatology. On the other hand, the PSQI scores appeared to significantly increase with the lack of symptom control: FC, 2.0 (1-4); PC, 3.5 (2-5); UC, 6.6 (4-8) ( p  = 0.002). The SA-SDQ questionnaire results significantly increased with the loss of asthma control: FC, 11.0 (9-12); PC, 12.5 (10-14); UC, 15.1 (14-16) ( p  = 0.005).

CONCLUSIONS: These results confirm and extend previous findings showing that there is a higher likelihood that underlying unknown sleep disturbances worsen asthma control, suggesting that a more comprehensive assessment is necessary to clarify the cause of nocturnal symptoms in asthma.