NEW YORK (Reuters Health) - Inhaled corticosteroid therapy can improve lung function in patients with chronic obstructive pulmonary disease (COPD), but after 6 months the decline in FEV1 resumes, according to a pooled analysis of trial data.

Inhaled corticosteroids are a mainstay of treatment for COPD patients who have an FEV1 of <50% predicted with frequent exacerbations. "Whether inhaled corticosteroid therapy can actually modify the natural history of COPD, however, is controversial," lead author Dr. Joan B. Soriano told Reuters Health.

Prior meta-analyses examining this topic have been methodologically heterogenous and have been unable to provide definitive results, explained Dr. Soriano, from Recinte Hospital Joan March in Mallorca, Spain. The present analysis is enhanced through the use of pooled patient-level data, he added.

The study, reported in the March issue of Chest, used data from seven randomized controlled trials (duration of at least 12 months) comparing inhaled steroid therapy with placebo. A total of 3911 subjects (29.2% female) with moderate-to-severe COPD were included in the study.

In the first 6 months, inhaled corticosteroid use was associated with a 2.42% average improvement in FEV1 relative to placebo (p < 0.01). This translates into increases of 42 mL and 29 mL in men and women, respectively. The benefit was most pronounced in ex-smokers, rather than current smokers, and in women.

After this initial boost, however, the rate of decline in FEV1 from 6 to 36 months was not significantly different between patients treated with inhaled steroids and those given placebo.

"Our analysis provides the final answer to the final question" of whether inhaled steroids alter the natural course of COPD, Dr. Soriano said. "The answer is no."

Still, he does not believe that this finding will lead to a reduction in the use of inhaled steroids for moderate-to-severe COPD since these agents have been shown to "reduce symptoms and produce meaningful improvements in quality of life."

While inhaled corticosteroids do not slow the decline in FEV1 seen with COPD, Dr. Soriano cited three interventions that do: smoking cessation, lung volume reduction surgery, and oxygen therapy.