Patient characteristics according to the skeletal muscle index and serum creatinine level
| Variable | Categorization | Low SMI (n=270) | High SMI (n=784) | P-value | Low creatinine (n=748) | High creatinine (n=306) | P-value |
|---|---|---|---|---|---|---|---|
| Sex | Female | 148 (54.8) | 284 (36.2) | 307 (41.0) | 125 (40.8) | ||
| Male | 122 (45.2) | 500 (63.8) | <0.001 | 441 (59.0) | 181 (59.2) | >0.999 | |
| Age (yr) | <70 | 168 (62.2) | 545 (69.5) | 546 (73.0) | 167 (54.6) | ||
| ≥70 | 102 (37.8) | 239 (30.5) | 0.033 | 202 (27.0) | 139 (45.4) | <0.001 | |
| Diabetes mellitus | No | 226 (83.7) | 625 (79.7) | 622 (83.2) | 229 (74.8) | ||
| Yes | 44 (16.3) | 159 (20.3) | 0.179 | 126 (16.8) | 77 (25.2) | 0.003 | |
| Hypertension | No | 168 (62.2) | 436 (55.6) | 469 (62.7) | 135 (44.1) | ||
| Yes | 102 (37.8) | 348 (44.4) | 0.068 | 279 (37.3) | 171 (55.9) | <0.001 | |
| Smoking | No | 198 (73.3) | 528 (67.3) | 508 (67.9) | 218 (71.2) | ||
| Yes | 72 (26.7) | 256 (32.7) | 0.079 | 240 (32.1) | 88 (28.8) | 0.324 | |
| BMI (kg/m2) | 21.8±3.2 | 24.1±2.8 | <0.001 | 23.4±3.0 | 23.7±3.2 | 0.226 | |
| CEA (ng/mL) | <5 | 181 (67.0) | 548 (69.9) | 515 (68.9) | 214 (69.9) | ||
| ≥5 | 75 (27.8) | 202 (25.8) | 193 (25.8) | 84 (27.5) | |||
| Unknown | 14 (5.2) | 34 (4.3) | 0.649 | 40 (5.3) | 8 (2.6) | 0.148 | |
| Tumor location | Colon | 201 (74.4) | 534 (68.1) | 528 (70.6) | 207 (67.6) | ||
| Rectum | 69 (25.6) | 250 (31.9) | 0.061 | 220 (29.4) | 99 (32.4) | 0.385 | |
| Histologic grade | G1 & G2 | 249 (92.2) | 723 (92.2) | 691 (92.4) | 281 (91.8) | ||
| G3 & MC & SRC | 21 (7.8) | 61 (7.8) | >0.99 | 57 (7.6) | 25 (8.2) | 0.861 | |
| LVI | Absent | 181 (67.0) | 550 (70.2) | 524 (70.1) | 207 (67.6) | ||
| Present | 58 (21.5) | 157 (20.0) | 152 (20.3) | 63 (20.6) | |||
| Unknown | 31 (11.5) | 77 (9.8) | 0.597 | 72 (9.6) | 36 (11.8) | 0.560 | |
| Lymph nodes | <12 | 39 (14.4) | 125 (15.9) | 90 (12.0) | 74 (24.2) | ||
| ≥12 | 231 (85.6) | 659 (84.1) | 0.625 | 658 (88.0) | 232 (75.8) | <0.001 | |
| Stage | I | 56 (20.7) | 213 (27.2) | 201 (26.9) | 68 (22.2) | ||
| II | 96 (35.6) | 252 (32.1) | 248 (33.2) | 100 (32.7) | |||
| III | 118 (43.7) | 319 (40.7) | 0.111 | 299 (40.0) | 138 (45.1) | 0.199 | |
| Complications | No | 206 (76.3) | 608 (77.6) | 598 (79.9) | 216 (70.6) | ||
| Yes | 64 (23.7) | 176 (22.4) | 0.734 | 150 (20.1) | 90 (29.4) | 0.001 | |
| Chemotherapy | No | 124 (45.9) | 302 (38.5) | 316 (42.2) | 110 (35.9) | ||
| Yes | 146 (54.1) | 482 (61.5) | 0.039 | 432 (57.8) | 196 (64.1) | 0.068 | |
| Index year | 2006–2009 | 113 (41.9) | 329 (42.0) | 250 (33.4) | 192 (62.7) | ||
| 2010–2014 | 157 (58.1) | 455 (58.0) | >0.99 | 498 (66.6) | 114 (37.3) | <0.001 | |
| Creatinine (mg/dL) | 0.8±0.2 | 0.9±0.4 | <0.001 | 0.7±0.2 | 1.1±0.5 | <0.001 | |
| SMI (cm2/m2) | 39.1±5.6 | 51.7±7.0 | <0.001 | 48.2±8.7 | 49.0±8.4 | 0.189 | |
| SMD (HU) | 41.0±8.7 | 42.8±8.4 | 0.004 | 42.6±8.3 | 41.5±8.9 | 0.054 |
Values are presented as number (%) or mean±standard deviation.
SMI = skeletal muscle index; BMI = body mass index; CEA = carcinoembryonic antigen; G1 = no sarcopenia with low serum creatinine level; G2 = no sarcopenia with high serum creatinine levels; G3 = sarcopenia with low serum creatinine level; MC = mucinous adenocarcinoma; SRC = signet-ring cell; LVI = lymphovascular invasion; SMD = skeletal muscle radiodensity; HU = Hounsfield unit.