Increased capillary filtration of albumin in diabetic patients--relation with gender, hypertension, microangiopathy, and neuropathy.

The aim of this study was to investigate the factors associated with an increase in capillary filtration of albumin (CFA) in a large series of diabetic patients and its relationship with gender, hypertension, microangiopathy, and neuropathy. One hundred sixty-three unselected diabetic patients, 74 type I and 89 type II, were included. An isotopic test of CFA was performed with 99m technetium-labeled albumin injected intravenously. Radioactivity was counted externally at the forearm with a gamma camera before, during, and after venous compression. After removal of venous compression, interstitial albumin retention (AR) was calculated and the radioactivity disappearance curve was analyzed by the Fast Fourier transform, which provides an index for lymphatic uptake of interstitial albumin (low-frequency to high-frequency amplitude peak ratio [LF/HF]). An increase in AR and LF/HF was found in 65 (39.9%) and 117 (71.7%) patients, respectively. Increased AR was significantly more frequent in women than in men (P=.018) and in patients without microangiopathic complications than in those with them (P=.028). In men, it was significantly more frequent in type I versus type II diabetic patients (P=.004), and AR was significantly higher in patients with peripheral neuropathy than in those without (P=.004). The LF/HF was also significantly higher in men with peripheral neuropathy (P=.045). In women, the AR level correlated negatively with postprandial glycemia (P=.006) and was significantly higher in patients without microangiopathic complications (P=.003). These data suggest the role of hormonal factors, both sex steroids and insulin, and the major role of peripheral neuropathy in the increase in CFA. The highly prevalent increase in CFA before the onset of microangiopathic complications is consistent with the presence of a functional microcirculatory disorder that might contribute to the occurrence of microangiopathic lesions.