Characteristics of the study population stratified by amputation status
| Total (n=92 929) | No amputation (n=91 203) | Major amputation (n=1726) | P value | |
| Demographics | ||||
| Age, mean (SD) | 71.87 (11.86) | 71.96 (11.85) | 67.06 (12.51) | <0.0001 |
| Age group | ||||
| <65 years | 23 212 (24.98) | 22 477 (24.65) | 735 (42.58) | <0.0001 |
| ≥65 years | 69 717 (75.02) | 68 726 (75.35) | 991 (57.42) | |
| Gender | ||||
| Male | 42 508 (45.74) | 41 423 (45.42) | 1085 (62.86) | <0.0001 |
| Female | 50 421 (54.26) | 49 780 (54.58) | 641 (37.14) | |
| Socioeconomic factors | ||||
| Disability | 28 683 (30.87) | 27 814 (30.50) | 869 (50.35) | <0.0001 |
| Low income subsidy | 59 063 (63.56) | 57 802 (63.38) | 1261 (73.06) | <0.0001 |
| Country residence | ||||
| Metropolitan | 76 248 (82.05) | 74 958 (82.19) | 1290 (74.74) | <0.0001 |
| Non-metropolitan | 16 534 (17.79) | 16 100 (17.65) | 434 (25.14) | |
| Unknown | 147 (0.16) | 145 (0.16) | 2 (1.36) | |
| Median income | ||||
| Q1 | 23 353 (25.13) | 22 767 (24.96) | 586 (33.95) | <0.0001 |
| Q2 | 23 343 (25.12) | 22 872 (25.08) | 471 (27.29) | |
| Q3 | 23 063 (24.82) | 22 688 (24.88) | 375 (21.73) | |
| Q4 | 23 170 (24.93) | 22 876 (25.08) | 294 (17.03) | |
| Poverty | ||||
| <20% | 73 137 (78.70) | 71 889 (78.82) | 1248 (72.31) | <0.0001 |
| ≥20% | 19 792 (21.30) | 19 314 (21.18) | 478 (27.69) | |
| Medical history | ||||
| ESRD | 2448 (2.63) | 2192 (2.40) | 256 (14.83) | <0.0001 |
| PAD | 49 774 (53.56) | 48 307 (52.97) | 1467 (84.99) | <0.0001 |
| Insulin | 14 672 (15.79) | 14 131 (15.49) | 541 (31.34) | <0.0001 |
| Elixhauser comorbidity index, mean (SD) (range 0–29) | 3.87 (2.88) | 3.85 (2.87) | 4.98 (3.35) | <0.0001 |
| DCSI, mean (SD) (range 0–13) | 2.12 (1.35) | 2.11 (1.35) | 3.06 (1.39) | <0.0001 |
| Index diagnosis | ||||
| DFU | 29 696 (31.96) | 28 930 (31.72) | 766 (44.38) | <0.0001 |
| DFI | 63 233 (68.04) | 62 273 (68.28) | 960 (55.62) | <0.0001 |
| Specialty for DFU/DFI diagnosis | ||||
| Primary care | 10 806 (11.63) | 10 681 (11.71) | 125 (7.24) | <0.0001 |
| Podiatry | 20 625 (22.19) | 20 439 (22.41) | 186 (10.78) | |
| Specialist | 61 498 (66.18) | 60 083 (65.88) | 1415 (81.98) | |
| Place of DFU/DFI diagnosis | ||||
| Hospital | 6814 (7.33) | 6350 (6.96) | 464 (26.88) | <0.0001 |
| Outpatient | 49 979 (53.78) | 49 329 (54.09) | 650 (37.66) | |
| ED | 1845 (1.99) | 1757 (1.93) | 88 (5.10) | |
| Home health agency | 606 (0.65) | 598 (0.66) | 8 (0.46) | |
| Skilled nursing facility | 3546 (3.82) | 3479 (3.81) | 67 (3.88) | |
| Other | 30 139 (32.43) | 29 690 (32.55) | 449 (26.01) | |
| Early PCP follow-up (30 days after diagnosis) | 45 727 (49.21) | 44 639 (48.94) | 1088 (63.04) | <0.0001 |
| Revascularization within 12 months | 8178 (8.80) | 7288 (7.99) | 890 (51.56) | <0.0001 |
| Healthcare utilization after diagnosis | ||||
| ED visits per person, mean (SD) | 0.63 (1.36) | 0.63 (1.35) | 1.09 (1.73) | <0.0001 |
| Outpatient visits per person, mean (SD) | 3.19 (5.91) | 3.22 (5.93) | 1.14 (4.45) | <0.0001 |
| Inpatient hospital stay per person, mean (SD) | 16.06 (29.84) | 15.70 (29.50) | 35.08 (44.16) | <0.0001 |
Values are reported as number (%) unless otherwise specified.
DCSI, Diabetes Complications Severity Index; DFI, diabetic foot infection; DFU, diabetic foot ulcer; ED, emergency room; ESRD, end-stage renal disease; PAD, peripheral artery disease; PCP, primary care physician; Q, quartile.