Diabetes mellitus vs. Raynaud disease: different lung vascular bed disorders

In type II diabetes mellitus there are few data concerning pulmonary function abnormalities. In normal subjects and in patients with primary Raynaud phenomenon, cold pressor test induces a decrease in carbon monoxide single-breath diffusing capacity (DL,co) but not in secondary Raynaud phenomenon. Our objective was to assess evaluation of lung diffusion capacity postural changes in diabetes mellitus and in secondary Raynaud phenomenon, two diseases with different pulmonary capillaries functional disorders.

Twenty-five patients with type II diabetes mellitus (mean age 52.24 years), 17 patients with secondary Raynaud phenomenon (mean age 47.06 years), non-smokers without pulmonary or heart disease, and 26 healthy matched subjects (mean age 47.50 years) underwent lung diffusion capacity measurements by single-breath method also corrected by alveolar volume (DL,co) in sitting and supine positions.

Patients with diabetes mellitus exhibited lower values of DL,co and DL,co/VA measurements in comparison with subjects with Raynaud phenomenon and control group (p <0.01). Additionally, they had a significant decrease in DL,co in supine compared to sitting position (83.88 +/- 16.53 vs. 89.68 +/- 18.03, p = 0.023). To the contrary, supine position in secondary Raynaud phenomenon and in control group after cold pressor test showed a significant increase in DL,co/VA (120.93 vs. 109.78 in Raynaud and 114.36 vs. 99.47 in control group, p <0.001).

Postural changes of lung diffusion capacity could be used as a simple, non-invasive method to detect vascular disease resulting from different pathophysiologic mechanisms such as diabetes mellitus and Raynaud phenomenon.