Dysfunctional Breathing Linked to Poor Asthma Control in Patients

New research suggests that dysfunctional breathing has strong connections to poor asthma control and can be misdiagnosed in clinical settings when asthma patients have co-existing issues with dysfunctional breathing (DB).

The most common symptoms of the respiratory disorder, DB can include "dyspnea, exercise-induced breathlessness, sleep sighing, frequent yawning and hyperventilation" leading to respiratory complaints such as "fatigue, light-headedness, and anxiety."

Patients with dysfunctional breathing, alternately called "Hyperventilation Syndrome" (HVS) because sufferers breathe too deeply or too rapidly, are often diagnosed in-clinic via questionnaire, but those questionnaires themselves sometimes skew diagnoses towards either asthma or HVS/DB without identifying them as co-existent issues.

These misdiagnoses can lead, at times, to overmedication and overtreatment in asthma patients, and patients with both asthma and dysfunctional breathing could benefit from breathing therapies to improve asthma control, reported members of the Respiratory Research Unit of the Department of Respiratory Medicine at Bispebjerg University Hospital in Copenhagen, Denmark.

Diagnostic tools like the Nijmegen questionnaire contain a number of standardized questions that assist clinicians with diagnosing hyperventilation syndrome/DB in general patients, but there is no technique or tool "validated to identify DB in the presence of asthma”. The difficulty lies in distinguishing HVS/DB from asthma symptoms when the two co-exist, and evaluating the impact of HVS/DB on asthma control levels.

HVS/DB is a relatively common ailment (approximately 8% of adults suffer from HVS/DB), and its causes range from the physiological to the psychological. The study reported that there has been little examination of the links between HVS/DB and asthma, although "it is known that asthmatic patients with DB have lower quality of life scores, higher prevalence of anxiety and a lower sense of coherence compared to patients without DB”.

In order to better determine the connections between and effects of HVS/DB on patients with asthma, the cross-sectional MAPOUT-II study completed by the Respiratory Research Unit collected data from 190 (out of 256 total) patients referred to specialists at the Respiratory Outpatient Clinic at Bispebjerg Hospital in Copenhagen during a 12-month period. Veidal explained "all subjects had a three-day asthma evaluation program within a 14-day period."

The evaluation program included spirometry readings, fractional exhaled nitric oxide (FeNO) measurement for inflammation, as well as a "bronchial challenge with methacholine," a "skin prick test with 10 standard allergens," and a "mannitol bronchial provocation." Patients were also interviewed using Global Initiative for Asthma (GINA) guidelines, five-question Asthma control Questionnaire (ACQ-5), Nijmegen questionnaire, and Quality of Life Questionnaire (mini-AQLQ). All patients were asked to measure their peak-flow variability twice a day for two weeks.

The study found that of the patients studied 31 (24.41%) also suffered from HVS/DB, and that "asthmatic patients with co-existing DB had a poorer asthma control compared to asthmatics without DB." Data revealed that patients with both asthma and HVS/DB had a "lower quality of life, higher self-estimated asthma severity, and more frequent exacerbations."

Additionally, researchers found that HVS/DB effects were an independent determinant when it came to ACQ and Nijmegen scores. Responses to specific questions on both questionnaires could lead to an overestimation of HVS/DB in patients with asthma and vice versa. Veidal and colleagues concluded that the frequent co-morbidity of the respiratory disorders suggested a need for routine screening to determine if HVS/DB was an underlying factor for patients with asthma.

Veidal and colleagues suggested that once identified, those patients with both HVS/DB and asthma might benefit from physiotherapy-based breathing retraining as part of a regimen to regain asthma control. Veidal wrote that at present there is "a need for larger studies validating the efficacy of specific breathing retraining programs" on asthma which could, theoretically, improve asthma control and help reduce the need for corticosteroids in the long run, thus improving quality of life for patients.

The article "The impact of dysfunctional breathing on the assessment of asthma control," appears in the February 2017 issue of Respiratory Medicine.

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