Patients with chronic obstructive pulmonary disease (COPD) experience a progressive, irreversible decline in lung function. For these patients, smoking cessation is the only intervention with proven benefit. Although inhaled steroids often are prescribed for COPD, it is unclear if these medications affect health outcomes or if long-term use causes adverse effects. Gartlehner and colleagues conducted a systematic review of the effectiveness and safety of inhaled steroids to characterize the risks and benefits of these medications.
Relevant English-language articles published between 1970 and April 2005 were identified using multiple databases. For data on effectiveness, only double-blind randomized controlled trials (RCTs) lasting more than six months were included. Because the trials had varying definitions for a COPD exacerbation, the authors used the most common definition: an episode requiring corticosteroids, antibiotics, an emergency department visit, or hospitalization. For data on adverse events, observational studies and mixed studies involving patients with asthma were included. Studies determined to be of poor quality using criteria developed by the U.S. Preventive Services Task Force were excluded. Of 880 abstracts identified, 23 were included in the systematic review: 12 RCTs on effectiveness and 11 studies on adverse events. Data were then extracted and pooled, if possible, to assess the effect of inhaled steroids on exacerbations, mortality, quality of life, respiratory symptoms, and adverse events in patients with COPD.
Patients with moderate to severe COPD (i.e., forced expiratory volume in one second [FEV1] less than 80 percent of predicted)who were treated with inhaled steroids were 33 percent less likely than those treated with placebo to experience an exacerbation over the 17.7-month follow-up period (number needed to treat to avoid one exacerbation = 12). There was no difference in benefit between newer and older inhaled steroids. Patients with mild COPD (i.e., FEV1 80 percent or more of predicted) who used inhaled steroids experienced no fewer exacerbations than patients treated with placebo. Regardless of disease severity, treatment had no effect on quality of life, respiratory symptoms, or all-cause mortality. Observational studies suggested that inhaled steroid use is associated with modest decreases in bone mineral density and increases in cataracts and open-angle glaucoma. These rare adverse effects were generally associated with long-term use at high dosages.
The authors conclude that inhaled steroid treatment reduces the frequency of exacerbations in patients with moderate to severe COPD, but it does not affect overall mortality. Adverse events appeared to be mild and infrequent. Because this systematic review may not have included a sufficient number of patients to find differences in mortality and quality of life, the authors suggest that additional large studies be conducted. One such study is TORCH (Towards a Revolution in COPD Health), a multicenter RCT. Data collection for this trial should be complete in 2006.