Chronic obstructive pulmonary disease and diabetes mellitus: a systematic review of the literature.

The objective of this systematic review was to discuss our current understanding of the complex relationship between chronic obstructive pulmonary disease (COPD) and type-2 diabetes mellitus (T2DM). We performed a systematic search of the literature related to both COPD and diabetes using PubMed. Relevant data connecting both diseases were compiled and discussed. Recent evidence suggests that diabetes can worsen the progression and prognosis of COPD; this may result from the direct effects of hyperglycemia on lung physiology, inflammation or susceptibility to bacterial infection. Conversely, it has also been suggested that COPD increases the risk of developing T2DM as a consequence of inflammatory processes and/or therapeutic side effects related to the use of high-dose corticosteroids. In conclusion, although there is evidence to support a connection between COPD and diabetes, additional research is needed to better understand these relationships and their possible implications.