Table 4.
The cut-off points of FLI stratified by waist circumference and BMI based on the results of conventional ultrasonography in NHANES III
| Stratification | Total | Fatty liver | Prevalence (%) | Cut-off points | AUROC | Sensitivity (true positive fraction) (%) | Specificity (true negative fraction) (%) | Positive likelihood ratio | Negative likelihood ratio | Youden index | P value |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Total | 9214 | 3166 | 34.36 | > 59.54 | 0.681 (0.671–0.691) | 55.53 (53.8–57.3) | 75.15 (74.0–76.2) | 2.23 | 0.59 | 0.3068 | < 0.0001 |
| Male | 4290 | 1530 | 35.66 | > 61.47 | 0.706 (0.692–0.720) | 58.63 (56.1–61.1) | 74.82 (73.2–76.4) | 2.33 | 0.55 | 0.3345 | < 0.0001 |
| Female | 4924 | 1636 | 33.23 | > 51.65 | 0.659 (0.645–0.672) | 56.6 (54.2–59.0) | 71.65 (70.1–73.2) | 2.00 | 0.61 | 0.2826 | < 0.0001 |
| Stratified by BMI | |||||||||||
| BMI < 18.5a | 190 | 55 | 28.95 | ≤ 3.80 | 0.582 (0.508–0.653) | 76.36 (63.0–86.8) | 40.74 (32.4–49.5) | 1.29 | 0.58 | 0.1710 | 0.0797 |
| 18.5 ≤ BMI < 25.0 | 3478 | 831 | 23.89 | > 23.63 | 0.527 (0.511–0.544) | 33.57 (30.4–36.9) | 76.39 (74.7–78.0) | 1.42 | 0.87 | 0.09962 | 0.0239 |
| 25.0 ≤ MI < 30.0 | 3191 | 1059 | 33.19 | > 60.84 | 0.682 (0.666–0.698) | 51.46 (48.4–54.5) | 76.22 (74.4–78.0) | 2.16 | 0.64 | 0.2768 | < 0.0001 |
| BMI ≥ 30.0 | 2355 | 1221 | 51.85 | > 84.10 | 0.688 (0.669–0.707) | 69.04 (66.4–71.6) | 60.14 (57.2–63.0) | 1.73 | 0.51 | 0.2918 | < 0.0001 |
| Male | |||||||||||
| BMI < 18.5a | 51 | 14 | 27.45 | ≤ 3.74 | 0.670 (0.524–0.795) | 71.43 (41.9–91.6) | 64.86 (47.5–79.8) | 2.03 | 0.44 | 0.3629 | 0.0625 |
| 18.5 ≤ BMI < 25.0 | 1632 | 387 | 23.71 | > 23.75 | 0.563 (0.538–0.587) | 49.10 (44.0–54.2) | 64.90 (62.2–67.6) | 1.4 | 0.78 | 0.1400 | 0.0004 |
| 25.0 ≤ BMI < 30.0 | 1741 | 609 | 34.98 | > 60.47 | 0.683 (0.660–0.704) | 61.58 (57.6–65.5) | 6.70 (63.9–69.4) | 1.85 | 0.58 | 0.2827 | < 0.0001 |
| BMI ≥ 30.0 | 866 | 520 | 60.05 | > 87.90 | 0.684 (0.652–0.715) | 65.77 (61.5–69.8) | 63.29 (58.0–68.4) | 1.79 | 0.54 | 0.2906 | < 0.0001 |
| Female | |||||||||||
| BMI < 18.5a | 139 | 41 | 29.50 | ≤ 1.23 | 0.559 (0.473–0.644) | 21.95 (10.6–37.6) | 95.92 (89.9–98.9) | 5.38 | 0.81 | 0.1787 | 0.2880 |
| 18.5 ≤ BMI < 25.0 | 1846 | 444 | 24.05 | > 23.65 | 0.504 (0.481–0.527) | 19.82 (16.2–23.8) | 89.95 (85.1–88.7) | 1.52 | 0.92 | 0.06767 | 0.8171 |
| 25.0 ≤ BMI < 30.0 | 1450 | 450 | 31.03 | > 45.44 | 0.679 (0.654–0.703) | 60.67 (56.0–65.2) | 70.40 (67.5–73.2) | 2.05 | 0.56 | 0.3107 | < 0.0001 |
| BMI ≥ 30.0 | 1489 | 701 | 47.08 | > 82.60 | 0.680 (0.656–0.704) | 67.05 (63.4–70.50 | 61.80 (58.3–65.2) | 1.76 | 0.53 | 0.2885 | < 0.0001 |
| Stratified by BMI and WC | |||||||||||
| Male | |||||||||||
| WC < 102 | 3145 | 862 | 27.41 | > 47.97 | 0.624 (0.607–0.641) | 46.98 (43.6–50.4) | 74.2 (72.4–76.0) | 1.82 | 0.71 | 0.2118 | < 0.0001 |
| BMI < 18.5a | 51 | 14 | 27.45 | ≤ 3.74 | 0.670 (0.524–0.795) | 71.43 (41.9–91.6) | 64.86 (47.5–79.8) | 2.03 | 0.44 | 0.3629 | 0.0625 |
| 18.5 ≤ BMI < 25.0 | 1620 | 382 | 23.58 | > 23.75 | 0.560 (0.535–0.584) | 48.43 (43.3–53.6) | 65.27 (62.5–67.9) | 1.39 | 0.79 | 0.1370 | 0.0008 |
| 25.0 ≤ BMI < 30.0 | 1353 | 420 | 31.04 | > 59.10 | 0.672 (0.647–0.697) | 53.57 (48.7–58.4) | 72.35 (69.4–75.2) | 1.94 | 0.64 | 0.2592 | < 0.0001 |
| BMI ≥ 30.0 | 121 | 46 | 38.02 | > 79.25 | 0.688 (0.598–0.769) | 50.00 (34.9–65.1) | 80.00 (69.2–88.4) | 2.5 | 0.63 | 0.3000 | 0.0002 |
| WC ≥ 102 | 1145 | 668 | 58.34 | > 87.73 | 0.665 (0.637–0.692) | 56.59 (52.7–60.4) | 70.23 (65.9–74.3) | 1.90 | 0.62 | 0.2682 | < 0.0001 |
| BMI < 18.5b | 0 | ||||||||||
| 18.5 ≤ BMI < 25.0 | 12 | 5 | 41.67 | > 54.66 | 0.657 (0.340–0.895) | 40.00 (5.3–85.3) | 100 (59.0–100.0) | - | 0.6 | 0.4 | 0.3989 |
| 25.0 ≤ BMI < 30.0 | 388 | 189 | 48.71 | > 67.07 | 0.623 (0.573–0.672) | 74.60 (67.8–806) | 45.23 (38.2–52.4) | 1.36 | 0.56 | 0.1983 | < 0.0001 |
| BMI ≥ 30.0 | 745 | 474 | 63.62 | > 88.53 | 0.653 (0.618–0.687) | 67.51 (63.1–71.7) | 56.83 (50.7–62.8) | 0.56 | 0.57 | 0.2434 | < 0.0001 |
| Female | |||||||||||
| WC < 88a | 2323 | 552 | 23.76 | ≤ 3.46 | 0.510 (0.489–0.530) | 20.11 (16.8–23.7) | 86.73 (85.1–88.3) | 1.52 | 0.92 | 0.06839 | 0.5030 |
| BMI < 18.5a | 138 | 41 | 29.71 | ≤ 1.23 | 0.555 (0.468–0.640) | 21.95 (10.6–37.6) | 95.88 (89.8–98.9) | 5.32 | 0.81 | 0.1783 | 0.3272 |
| 18.5 ≤ BMI < 25.0a | 1663 | 394 | 23.69 | ≤ 3.46 | 0.510 (0.486–0.535) | 20.56 (16.7–24.9) | 86.68 (84.7–88.5) | 1.54 | 0.92 | 0.07241 | 0.5536 |
| 25.0 ≤ BMI < 30.0 | 489 | 110 | 22.49 | > 41.89 | 0.562 (0.516–0.606) | 28.18 (20.0–37.6) | 89.18 (85.6–92.1) | 2.61 | 0.81 | 0.1736 | 0.0697 |
| BMI ≥ 30.0 | 33 | 7 | 21.21 | > 27.91 | 0.599 (0.414–0.765) | 100.0 (59.0–100.0) | 26.92 (11.6–47.8) | 1.37 | 0.00 | 0.2692 | 0.4221 |
| WC ≥ 88 | 2601 | 1084 | 41.68 | > 70.28 | 0.685 (0.667–0.703) | 62.18 (59.2–65.1) | 65.66 (63.2–68.0) | 1.81 | 0.58 | 0.2783 | < 0.0001 |
| BMI < 18.5b | 1 | 0 | |||||||||
| 18.5 ≤ BMI < 25.0 | 183 | 50 | 27.32 | > 35.26 | 0.552 (0.476–0.625) | 44.0 (30.0–58.7) | 67.67 (59.0–75.5) | 1.36 | 0.83 | 0.1167 | 0.2748 |
| 25.0 ≤ BMI < 30.0 | 961 | 340 | 35.38 | > 51.64 | 0.694 (0.664–0.723) | 64.12 (58.8–69.2) | 66.18 (62.3–69.9) | 1.9 | 0.54 | 0.3030 | < 0.0001 |
| BMI ≥ 30.0 | 1456 | 694 | 47.66 | > 82.60 | 0.676 (0.651–0.700) | 67.72 (64.1–71.2) | 60.50 (56.9–64.0) | 1.71 | 0.53 | 0.2822 | < 0.0001 |
AUROC area under the receiver operating characteristic curves, BMI body mass index, WC waist circumference
aThe calculated AUROC < 0.5, which cannot meet the requirements of diagnostic test
bThe optimal cut-off point of FLI could not be obtained due to insufficient data