BMI and an Anthropometry-Based Estimate of Fat Mass Percentage Are Both Valid Discriminators of Cardiometabolic Risk: A Comparison with DXA and Bioimpedance

Table 4

Prediction/discrimination of hypertension with degree of obesity as defined by dual-energy X-ray absorptiometry (DXA) bioimpedance analysis (BIA), an anthropometry-based estimate of fat mass percentage (FM% equation) and BMI.

								ROC analyses^n
Reference method/model^a	New method/model^b	𝑛^𝑐		Reclassification index, %^f				IDI, %^k		Men		Women
		Cases^d	Non-cases^e	Net^g	𝑃^hnri	Cases^i	Non-cases^j	𝐼^lintegr.	𝑃^midi	ΔAUC^o	𝑃^p	ΔAUC	𝑃
Hypertension^q, grade 1 (≥140/90 mmHg)
DXA	BIA InBody^r	269	185	5%	0.214	−1%	6%	1.7%	0.017	0.03	0.127	0.06	0.000
	BMI	335	258	6%	0.220	2%	3%	1.9%	0.006	0.00	0.977	0.04	0.073
	Estimate^s	335	258	6%	0.208	2%	3%	1.5%	0.019	0.03	0.383	0.07	0.000
BIA InBody	BMI	269	185	4%	0.360	1%	3%	0.5%	0.534	−0.03	0.330	−0.03	0.147
	Estimate	269	185	3%	0.502	0%	3%	0.1%	0.885	0.00	0.979	0.01	0.606
BMI	Estimate	335	258	0%	0.803	0%	0%	−0.4%	0.144	0.03	0.021	0.04	0.000
Hypertension, grade 2 (≥160/100 mmHg)
DXA	BIA InBody	93	361	−1%	0.848	−4%	3%	1.4%	0.063	0.02	0.396	0.05	0.000
	BMI	117	476	−9%	0.128	−8%	−1%	−1.2%	0.049	−0.09	0.064	−0.03	0.255
	Estimate	117	476	−8%	0.154	−7%	−1%	−1.2%	0.036	−0.01	0.746	0.01	0.626
BIA InBody	BMI	93	361	−9%	0.161	−8%	−1%	−2.5%	0.003	−0.11	0.006	−0.08	0.000
	Estimate	93	361	−10%	0.096	−9%	−1%	−2.8%	0.001	−0.04	0.309	−0.04	0.044
BMI	Estimate	117	476	1%	0.682	1%	0%	0.0%	0.870	0.07	0.001	0.04	0.000
Dyslipidaemia^t
DXA	BIA InBody	111	304	−2%	0.616	−5%	3%	−0.1%	0.928	−0.03	0.161	−0.01	0.510
	BMI	124	345	6%	0.320	2%	4%	3.5%	0.015	−0.01	0.816	0.02	0.378
	Estimate	124	345	4%	0.496	0%	4%	2.7%	0.040	−0.02	0.640	0.01	0.766
BIA InBody	BMI	111	304	8%	0.149	6%	2%	3.1%	0.022	0.02	0.568	0.03	0.162
	Estimate	111	304	6%	0.240	5%	2%	2.5%	0.044	0.01	0.734	0.02	0.390
BMI	Estimate	124	345	−2%	0.237	−2%	−1%	−0.8%	0.111	−0.01	0.598	−0.01	0.148

aMethod of measurement, based on which participants are classified in categories of obesity.
^bDifferent method of estimating obesity, the predictive power of which is compared to reference model/reference method.
^cNumber of participants.
^dNumber of participants that are positive with regard to respective outcome.
^eNumber of participants that are negative with regard to respective outcome.
^fPercentage improvement (+) or deterioration (−) in predictive power of new model compared to reference model. Categories of obesity/FM% as independent variable.
^gNet reclassification of cases + net reclassification of noncases. A positive number denotes increased predictive power for the new model.
^hLikelihood of net reclassification index to be 0, that is, the new model showing no improvement/deterioration over reference model.
ⁱNet reclassification of cases = percentage of cases reclassified by the new model into a higher risk category − percentage of cases reclassified by the new model into a lower risk category
^jNet reclassification of non-cases = percentage of non-cases reclassified by the new model into a lower risk category − percentage of non-cases reclassified by the new model into a higher risk category.
^kIntegrated discrimination improvement (+) or deterioration (−) of new model compared to reference model. Categories of obesity/FM% as independent variable in an age-adjusted model.
^lMean difference in predicted individual probabilities between cases and non-cases for two models. A positive number denotes increased predictive power for the new model.
^mLikelihood of net reclassification index to be 0, that is, the new model showing no improvement/deterioration over reference model.
ⁿMeasures of obesity (BMI/FM%) as continuous variable in a logistic regression model predicting respective outcomes.
^oDifference in area under curve of receiver operating characteristic compared to reference method.
^pProbability of 0-hypothesis (no difference).
^qDefinitions of hypertension according to European Societies for Hypertension and Cardiology {Mancia, 2007 #2897}.
^rEstimation of FM% with bioimpedance device InBody (720) (Biospace, Korea).
^sAnthropometry-based estimate; arithmetic mean of FM% estimations according to prediction methods Deurenberg et al. [12], Gallagher et al. [15], and Larsson et al. [14].
^tTriacylglycerols ≥ 1.7 mmol/L or HDL cholesterol ≤ 1.29 mmol/L in men or HDL ≤ 1.03 mmol/L in women.