The Relationship of Morphology and Color of Nailfold Capillaries with Disease State of Diabetes and Obesity: An Observational Study

Abstract

Nailfold capillaries are small hairpin-shaped blood vessels that aline the nailfold at the tips of fingers and toes. Those vessels can be repeatedly observed using relatively inexpensive and small microscopy without injecting needles or administering drugs. Nailfold capillary morphology is known to be altered by various diseases, and morphological abnormalities have been associated with type 2 diabetes and its complications. Though, there have been few reports of quantitative analysis of nailfold capillary morphology. The conventional semi-quantitative analysis could only analyze the presence or absence of diseases and complications, so by shifting to quantitative analysis, nailfold capillaroscopy would be a new examination method in the treatment of type 2 diabetes, as it will provide more accurate results and also enable the evaluation of disease severity. In this study, we quantitatively analyzed not only the morphology of nailfold capillaries but also the colors of the capillaries, and showed that capillary diameters in hospitalized patients with diabetes had a significantly positive correlation with HbA1c levels, a glycemic control index that indicates the disease status of diabetes （R2=0.21, p=0.027）．Additionally, obesity, associated with insulin resistance in diabetes, had a significantly negative correlation with delta E, a color contrast between the inside and outside of capillaries in obese and diabetic patients （R2=0.19, p=0.035）．