Martha Kerr

October 06, 2008

October 6, 2008 (Berlin, Germany) — Two surveys of nearly 35,000 European adults with asthma show that 94% of patients are awakened at least once a month by asthma symptoms, and three quarters are awakened at least once a week. Furthermore, nocturnal asthma appears to be more prevalent in women than men.

The survey results were presented by investigators here at the European Respiratory Society 2008 Annual Congress.

The European Community Respiratory Health Survey (ECRHS) involved nearly 19,000 adults between the ages of 20 and 55 years, and the Respiratory Health in Northern Europe (RHINE) study comprised nearly 16,000 individuals in Sweden who originally participated in the ECRHS. Data from the surveys on nocturnal asthma were presented by Christer Janson, MD, professor of respiratory medicine and allergology at Uppsala University, in Sweden.

"Using lung-function measurements as the gold standard, analyses of these data suggest that night cough is only weakly related to lower lung function and airway obstruction," Dr. Janson announced.

"In addition, we find that women wake up at night because of coughing much more often than men do," he said. "One third of women report being bothered by night cough; this is almost twice as often as men, when differences in smoking, age, body mass index, social class, and treating center" are taken into account (odds ratio, 1.8; range, 1.68-1.92; P < .001), Dr. Janson said.

"Men and women with night cough as an only symptom have no reduced lung function and no measurable airway obstruction, while night cough together with other respiratory symptoms is associated with both lower lung function and with airway obstruction," Dr. Janson reported.

"Sleep disturbances and daytime sleepiness remain a considerable problem in asthma, despite improvement in therapy and management," Dr. Janson told Medscape Pulmonary Medicine. "Sleep disturbances are closely related to asthma control. Lifestyle variables, such as smoking, obesity, and lack of exercise, are also important risk factors for sleep disturbances in asthma."

Dr. Janson's data were corroborated by study findings presented by Monica Kraft, MD, professor of medicine at Duke University, in Durham, North Carolina.

A survey of 7729 outpatient asthmatics in the United Kingsom showed that 94% are awakened at least once a month with asthma symptoms, 74% are awakened at least once a week, 64% are awakened at least 3 times a week, and 39% are awakened every night with coughing and wheezing, Dr. Kraft reported.

In addition, she added, 53% of asthma-related deaths occur at night. "There is a circadian rhythm to the disease process, with the best airway function occurring around 4 pm, and the worst about 4 am," she told Congress attendees.

"Studies of cortisol levels, melanin, eosinophil count, and beta-adrenergic receptors show variability. The evidence indicates that there is a disconnect between the pituitary and the adrenals. There is a blunting of response," Dr. Kraft said.

"Beta-adrenergic-receptor availability is down, meaning salmeterol and other agents in the class can't bind. The number and function of glucocorticoid receptors is down in the early morning as well," she said. "Melanin is increased at night, which correlates with poorer lung function."

"The timing of therapies is important. Chronotherapy — we're not doing enough of that," Dr. Kraft said.

"We need to keep in mind that most asthma treatments have multiple steps to go through before they are active. It can take more than 6 hours before they even start to take effect," she explained in an interview with Medscape Pulmonary Medicine after her presentation.

"It would be better if we gave the nighttime dose in the late afternoon or early evening. These patients are not receiving the maximum effective dose when they need it most."

Dr. Janson added that "this is a population-based study. There is still a lot to do to determine the most effective treatment regimen, including its timing. And these data include patients with asthma that is not well treated. We could do a lot better."

"There are 2 big issues here," Dr. Kraft continued. "Adherence is a problem and chronotherapy is an issue. And those with nocturnal asthma probably also have poorly controlled daytime asthma."

Dr. Janson emphasized that the survey results show that women have more nighttime symptoms, especially cough, than men. "This is due largely to hormonal influences, including menopause, irregular menstruation, and exogenous sex hormones," he said.

Neither Dr. Janson nor Dr. Kraft have disclosed any relevant financial relationships.

European Respiratory Society (ERS) 2008 Annual Congress: Poster 1183. Presented October 5, 2008.

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