Table 2.

Receiver operating characteristic curve analyses with D7 faecal measurements as predictors

Predictor	Optimal cut-off	Positive class	Negative class	AUC	Sensitivity, %	Specificity, %	PPV, %	NPV, %	p-value
IC4/C2	0.039	100% EN [n = 25]	<100% EN [n = 36]	0.91	92	83	79	94	<0.001
IC4/C2 + C4	0.035	100% EN [n = 25]	<100% EN [n = 36]	0.92	92	83	79	94	<0.001
IC5/C4	0.362	100% EN [n = 25]	<100% EN [n = 36]	0.90	100	75	73	100	<0.001
Total BCFAs/C4	0.630	100% EN [n = 25]	<100% EN [n = 36]	0.90	100	75	73	100	<0.001
IC4/C4	0.269	100% EN [n = 25]	<100% EN [n = 36]	0.90	100	72	71	100	<0.001
C2 dry, μmol/g	239	100% EN [n = 25]	<100% EN [n = 36]	0.92	96	78	75	97	<0.001
Total SCFAs dry, μmol/g	347.4	100% EN [n = 25]	<100% EN [n = 36]	0.91	96	75	73	69	<0.001
Total SCFAs wet, μmol/g	93.1	100% EN [n = 25]	<100% EN [n = 36]	0.88	84	86	81	89	<0.001
pH	8	100% EN [n = 25]	<100% EN [n = 36]	0.91	84	86	81	89	<0.001
Total SCFAs, %	92.00	100% EN [n = 25]	<100% EN [n = 36]	0.92	76	92	86	85	<0.001
Total BCFAs, %	8.00	100% EN [n = 25]	<100% EN [n = 36]	0.92	76	92	86	85	<0.001
Total BCFAs/total SCFAs	0.087	100% EN [n = 25]	<100% EN [n = 36]	0.92	76	92	86	85	<0.001
IC4/C2	0.039	100% EN [n = 25]	85% EN [n = 12]	0.89	92	83	92	83	<0.001
IC4/C2 + C4	0.035	100% EN [n = 25]	85% EN [n = 12]	0.89	92	83	92	83	<0.001
IC4, %	2.7	100% EN [n = 25]	85% EN [n = 12]	0.90	88	83	92	77	<0.001
IC4/total SCFAs	0.028	100% EN [n = 25]	85% EN [n = 12]	0.90	88	83	92	77	<0.001
IC5/C2	0.056	100% EN [n = 25]	85% EN [n = 12]	0.89	88	83	92	77	<0.001
pH	8.1	100% EN [n = 25]	85% EN [n = 12]	0.78	76	75	86	60	0.001

AUC, area under the curve; BCFAS, branched chain fatty acids [isobutyrate + isovalerate]; C2, acetate; C4, butyrate; IC4, isobutyrate; IC5, isovalerate; NPV, negative predictive value; PPV, positive predictive value; SCFAS, short chain fatty acids [acetate + propionate + butyrate].