ROC and CART analysis of subcutaneous adipose tissue topography (SAT-Top) in type-2 diabetic women and healthy females

Women suffering from type-2 diabetes mellitus (NIDDM) show a more android f at pattern than healthy females, but to date no exact determination of thei r fat distribution differences exists. Measurements at 15 specified body si tes with an optical device, the LIPOMETER, provide a subcutaneous adipose t issue topography (SAT-Top) of the individual. SAT-Top of 20 female NIDDM pa tients and 122 healthy controls was measured. ROC curve analysis was applie d to evaluate the discriminative power of each body site and to provide cut off values. Then a classification tree by the CART algorithm was establishe d, showing SAT-Top differences between the two groups. Best discriminating results were achieved by the neck site (ROC area index = 0.76, sensitivity = 61.3%, specificity = 77.8%), the four sites of the thigh (area indices fr om 0.71 to 0.76), and a linear combination of all body sites stemming from a previous factor analysis, which provides condensed information of the ext remities SAT-Top (area index = 0.80, sensitivity = 80.4%, specificity = 64. 6%), The results could be improved by a summary measure of "android fat pat tern" (area index = 0.89, sensitivity = 73.6%, specificity = 88.3%) and a p roportional measure of SAT-distribution, the relative neck (area index = 0. 84, sensitivity = 83.0%, specificity = 70.5%). Overall, 136 (95.8%) of the 142 subjects were correctly classified by the classification tree (sensitiv ity = 75%, specificity = 99.2%). Both methods show the expected increased u pper trunk obesity and decreased lower body obesity of NIDDM women compared with healthy females. (C) 2000 Wiley-Liss, Inc.