Endocrine Abstracts

Introduction: Pathophysiologic mechanisms that connect type 2 diabetes mellitus (T2DM) and chronic obstructive pulmonary disease (COPD) are complex and still unknown as are any respiratory effects of antidiabetic agents. COPD increases insulin resistance by chronic inflammation, hypoxia and corticosteroid treatment while, on the other hand, insulin as an anabolic hormone stimulates post-prandial protein synthesis and oxidative phosphorylation in skeletal muscle so that insulin resistance seems to be an important factor in the development of skeletal muscle weakness. We aimed to assess the influence of metformin treatment on lung function and its potential clinical benefit considering the fact that, as oral insulin-sensiting agent, increases respiratory muscle strenght.

Methodology: Retrospective study included patients with both T2DM and COPD who were hospitalized for acute exacerbation of COPD defined following Anthonisen criteria. COPD exacerbation was treated according to American Thoracic and European Respiratory Society quidelines, T2DM with pre-existing antidiabetic therapy. Spirometric parametres and lenght of hospital stay were compared according to presence or absence of metformin. Unpaired t-test was used for statistical analysis.

Results: Thirty-four patients were enrolled of whom 23 (67.6%) treated with metformin (mean age 67.3±10.0 years; 52.2% males) and 11 (32.4%) with sulfonylureas and/or insulin (mean age 68±7.7 years; 63.6% males). Patients in metformin group had significantly better FEV1 (P=0.007) and Tiffneau index (P=0.017) while the difference in FVC showed a considerable trend toward significance (P=0.063). Among these patients, single dose of metformin 500 mg turned out to be sufficient for the beneficial effect on FEV1; further improvement in FEV1 with increased dosage was insignificant (P>0.05). However, there was no significant difference concerning length of stay among them: median 10.8 days in metformin group vs 13.5 in non-metformin group (P=0.129).

Conclusion: Treatment with metformin was associated with improvements in spirometric examinations in patients with both T2DM and COPD.