NEW YORK (Reuters Health) – In terms of quality of life for patients with COPD, the improvements in lung function and exacerbation frequency produced by phosphodiesterase 4 (PDE4) inhibitors seem to be offset by adverse side effects, according to a new systematic review published May 11 by the Cochrane Library.

Dr. Phillippa Poole, at the University of Auckland, and other colleagues in New Zealand note that the oral PDE4 inhibitors roflumilast and cilomilast are intended to reduce the airway inflammation and bronchoconstriction seen in COPD. To evaluate that efficacy and safety of these agents, the team identified 23 randomized trials comparing a PDE4 to placebo in a total of 15,668 COPD patients.

The pooled (no pun intended) data showed that PDE4 inhibitors significantly improved FEV1 over placebo by a mean difference of 45.59 mL. Also, treatment with PDE4 inhibitors significantly reduced the risk of COPD exacerbations (odds ratio, 0.78), the investigators report.

However, there was no change in exercise tolerance with PDE4 treatment, the team found.

Furthermore, treatment was associated with adverse events such as headache and GI upset, although these were not serious, and roflumilast was associated with weight loss.

Overall, improvements in quality of life were small (-1.04) as measured by the St George’s Respiratory Questionnaire, according to the report.

In their “Plain Language Summary,” Dr. Poole and colleagues conclude, “These medicines improve lung function and reduce the likelihood of a flare-up of COPD, however they have little effect on symptoms or quality of life over and above existing treatments.”

They add, “Longer studies are needed to see if these medicines improve survival for people with COPD,” but that might be problematic. As they point out, “Encouraging people with COPD to continue to take these medicines in the absence of symptomatic relief may be challenging.”

Cochrane Database Syst Rev 2011;5.