Long-term outcomes in chronic obstructive pulmonary disease patients: exploring the effects of inhalatory devices and their influence on the outcome

PURPOSE: Numerous systematic reviews have examined the outcomes in patients with chronic obstructive pulmonary disease managed with different therapeutic strategies. However, no such studies have specifically focused on the effect of inhalation devices. METHODS: A standard PubMed search was carried out in which we identified all randomized placebo-controlled trials conducted in patients with moderate-to-severe or severe chronic obstructive pulmonary disease. The clinical end points were exacerbations rate, incidence of pneumonia, and mortality. Meta-regression was employed to assess the effect of the device. For the incidence of exacerbations, an equivalence analysis was also carried out. RESULTS: A total of 37 studies were analyzed. Four different devices were used across these trials (Respimat(®), HandiHaler(®), Diskus, and Turbuhaler(®)). Our meta-regression analysis failed to show any significant difference between devices with regard to exacerbation rate. Equivalence was shown for some comparisons (HandiHaler(®) vs Respimat(®)), but not for others. In analyzing mortality, Respimat(®) was shown to worsen this end point in comparison with Turbuhaler(®) and HandiHaler(®). Moreover, Turbuhaler(®) showed a protective effect over Diskus in the incidence of pneumonia. CONCLUSION: The results of our analysis represent the first attempt to explore the effect of the type of device on long-term outcomes. One important limitation was that most drugs were associated with one particular device, and so the effects of drugs and devices could not be reliably differentiated from one another.