Asthma severity can be quite variable from week to week

January 2003

SAN DIEGO — Asthma severity can fluctuate markedly over time from mild to severe, particularly in those patients with asthma who are not taking controller medications frequently, according to a study presented recently at CHEST 2002, the annual meeting of the American College of Chest Physicians.

The study, by GlaxoSmithKline researchers, was a retrospective analysis of two previously conducted 12-week clinical trials that included patients who had used only beta-2-agonists — such as albuterol or salmeterol (Advair, GlaxoSmithKline) — for their asthma and were subsequently randomized to receive placebo and as-needed albuterol.

Researchers reviewed 85 patients who kept a daily diary of asthma symptoms, albuterol use and peak expiratory flow and determined the patients’ asthma severity based on NIH criteria.

The study team observed marked fluctuations in the severity of asthma.

At study baseline, all patients met the criteria for moderate-to-severe asthma, having a mean baseline FEV₁ (a measure of lung function) of 64% predicted and asthma symptoms and albuterol use 6.0 days per week and 4.7 days per week, respectively.

However, the percent of weeks the patients in these studies met criteria for intermittent, mild, moderate or severe asthma were 9.2%, 13.6%, 71.1% and 6.1% of weeks, respectively. The data were based on symptom scores, peak expiratory flow and albuterol use.

A variable and unpredictable disease

“The data demonstrate that asthma not controlled with maintenance medications can be a variable and unpredictable disease, with severity that changes from week to week,” said Paul Dorinsky, MD, the study’s lead researcher. “Physicians should recognize that asthma that is initially thought to be ‘mild,’ frequently becomes more severe if these patients are followed over time.”

Severity not predicted by any one factor

No one parameter reliably predicted overall severity for individual patients at any given point in time. Failure to consider this could result in either an underestimation or overestimation of asthma severity, study researchers said.

According to national and international treatment guidelines, patients with persistent asthma can be classified into one of three categories (mild, moderate or severe) based upon lung function, asthma symptoms, nighttime awakenings and exacerbations.

GSK officials said the study was conducted to determine whether a possible limitation of this classification system is that patients might not remain in any one severity category over time, which they said, is indeed the case for patients who have not yet been prescribed an inhaled corticosteroid.

For more information:

• Schulman, Ronca and Bucuvalas, Inc. and Glaxo-SmithKline. Asthma in America, Oct. 1998.
• American Lung Association. Epidemiology and Statistics Unit, Best Practices and Program Services. Trends in Asthma Morbidity and Mortality. Feb. 2002.
• National Center for Health Statistics. 2000 National Hospital Discharge Survey, Advanced Data No. 329. June 2002. CDC. Surveillance for asthma: United States, 1980-1999. MMWR. 2002;51(SS01):1-13.
• National Heart, Lung, and Blood Institute. MMWR: 2002 Chart Book on Cardiovascular, Lung, and Blood Diseases. May 2002.