Table 1.
Participant characteristics – data are n (%), unless otherwise stated
| Current foot ulceration | Lower extremity amputation | ||||||
|---|---|---|---|---|---|---|---|
| Total (N = 450) |
Yes (n = 45) |
No (n = 405) |
P-value* | Yes (n = 46) |
No (n = 404) |
P-value* | |
| Mean age (SD), years | 67.5 (13.2) | 69.0 (10.3) | 67.3 (13.5) | 0.33 | 65.4 (11.2) | 67.7 (13.4) | 0.25 |
| Male sex | 291 (64.7) | 36 (80.0) | 255 (63.0) | 0.035* | 37 (80.4) | 254 (62.9) | 0.028* |
| Mean body mass index (SD), kg/m 2 | 28.2 (6.6) | 29.1 (6.5) | 28.1 (6.6) | 0.30 | 30.4 (6.3) | 27.9 (6.6) | 0.014* |
| Current smoking | 54 (12.0) | 5 (11.1) | 49 (12.1) | 1.00 | 5 (10.9) | 49 (12.1) | 0.99 |
| Living alone | 75 (16.7) | 6 (13.3) | 69 (17.0) | 0.67 | 10 (21.7) | 65 (16.1) | 0.44 |
| Ethnicity | |||||||
| Indigenous Australian | 4 (0.9) | 0 (0) | 4 (1.0) | 1.00 | 1 (2.2) | 3 (0.7) | 0.88 |
| English | 85 (18.9) | 9 (20) | 76 (18.8) | 1.00 | 12 (26.1) | 73 (18.1) | 0.94 |
| European | 194 (43.1) | 16 (35.6) | 178 (44.0) | 0.36 | 14 (30.4) | 180 (44.6) | 0.60 |
| American | 4 (0.9) | 0 (0) | 4 (1.0) | 1.00 | 0 (0) | 4 (1.0) | 1.00 |
| African | 14 (3.1) | 1 (2.2) | 13 (3.2) | 1.00 | 2 (4.3) | 12 (3.0) | 0.95 |
| Asian | 67 (14.9) | 5 (11.1) | 62 (15.3) | 0.60 | 1 (2.2) | 66 (16.3) | 0.88 |
| Pacific Islander | 29 (6.4) | 3 (6.7) | 26 (6.4) | 1.00 | 5 (10.9) | 24 (5.9) | 0.33 |
| Othera | 53 (11.8) | 11 (24.4) | 42 (10.4) | 0.011* | 11 (23.9) | 42 (10.4) | 0.159 |
| Cause of ESRD | |||||||
| Diabetes mellitus | 180 (40.0) | 37 (82.2) | 143 (35.3) | <0.001* | 42 (91.3) | 138 (34.2) | 0.98 |
| Hypertension | 28 (6.2) | 1 (2.2) | 27 (6.7) | 0.40 | 1 (2.2) | 27 (6.7) | 0.82 |
| Glomerulonephritis | 97 (21.6) | 2 (4.4) | 95 (23.5) | 0.006* | 0 (0) | 97 (24.0) | 0.88 |
| Polycystic kidney disease | 22 (4.9) | 1 (2.2) | 21 (5.2) | 0.61 | 1 (2.2) | 21 (5.2) | 0.104 |
| Reflux | 19 (4.2) | 1 (2.2) | 18 (4.4) | 0.76 | 1 (2.2) | 18 (4.5) | 0.67 |
| Renovascular disease | 10 (2.2) | 0 (0) | 10 (2.5) | 0.59 | 1 (2.2) | 9 (2.2) | 0.58 |
| Vasculitis | 9 (2.0) | 0 (0) | 9 (2.2) | 0.65 | 0 (0) | 9 (2.2) | 0.64 |
| Unknown | 15 (3.3) | 1 (2.2) | 14 (3.5) | 1.00 | 0 (0) | 15 (3.7) | 0.37 |
| Other | 70 (15.6) | 2 (4.4) | 68 (16.8) | 0.05 | 0 (0) | 70 (17.3) | 0.88 |
| Dialysis treatment | |||||||
| Hemodialysis | 423 (94.0) | 42 (93.3) | 381 (94.1) | 1.00 | 43 (93.5) | 380 (94.1) | 0.41 |
| Peritoneal dialysis | |||||||
| CAPD | 9 (2.0) | 0 (0) | 9 (2.2) | 0.65 | 0 (0) | 9 (2.2) | 0.64 |
| APD | 18 (4.0) | 3 (6.7) | 15 (3.7) | 0.58 | 3 (6.5) | 15 (3.7) | 0.79 |
| Median duration of dialysis (IQR), months | 36.9 (16.6 to 70.1) | 37.5 (20.0 to 64.1) | 36.8 (16.5 to 71.8) | 0.91 | 38.3 (17.7 to 72.6) | 36.6 (16.6 to 69.5) | 0.77 |
| Diabetes mellitus | 226 (50.2) | 39 (86.7) | 187 (46.2) | <0.001* | 43 (93.5) | 183 (45.3) | <0.001* |
| Type 1 | 13 (5.8) | 4 (10.3) | 9 (4.8) | 0.34 | 7 (15.2) | 6 (1.5) | 0.003* |
| Type 2 | 213 (94.2) | 35 (89.7) | 178 (95.2) | 0.34 | 36 (78.3) | 177 (43.8) | 0.003* |
| Mean duration (SD), months | 256.3 (152.6) | 348.8 (167.6) | 237.0 (142.3) | <0.001* | 301.8 (163.1) | 245.6 (148.5) | 0.043* |
| Retinopathy | 132 (29.3) | 28 (62.2) | 104 (25.7) | <0.001* | 32 (69.6) | 100 (24.8) | <0.001* |
| Known peripheral neuropathyb | 70 (15.6) | 20 (44.4) | 50 (12.3) | <0.001* | 26 (56.5) | 44 (10.9) | <0.001* |
| Known peripheral arterial diseaseb | 79 (17.6) | 27 (60.0) | 52 (12.8) | <0.001* | 31 (67.4) | 48 (11.9) | <0.001* |
| Lower extremity revascularization procedure | 35 (7.8) | 22 (48.9) | 13 (3.2) | <0.001* | 20 (43.5) | 15 (3.7) | <0.001* |
| Hypertension (requiring medication) | 360 (80.0) | 36 (80.0) | 324 (80.0) | 1.00 | 40 (87.0) | 320 (79.2) | 0.29 |
| Dyslipidemia | 301 (66.9) | 38 (84.4) | 263 (64.9) | 0.013* | 39 (84.8) | 262 (64.9) | 0.011* |
| Ischemic heart disease | 263 (58.4) | 36 (80.0) | 227 (56.0) | 0.003* | 33 (71.7) | 230 (56.9) | 0.076 |
| Congestive cardiac failure | 122 (27.1) | 18 (40.0) | 104 (25.7) | 0.061 | 15 (32.6) | 107 (26.5) | 0.48 |
| Cerebrovascular disease | 104 (23.1) | 19 (42.2) | 85 (21.0) | 0.003* | 15 (32.6) | 89 (22.0) | 0.153 |
| Osteoarthritis | 192 (42.7) | 17 (37.8) | 175 (43.2) | 0.60 | 15 (32.6) | 177 (43.8) | 0.194 |
| Inflammatory arthritis | 183 (40.7) | 14 (31.1) | 169 (41.7) | 0.22 | 13 (28.3) | 170 (42.1) | 0.099 |
| Median C-reactive protein (SD), mg/L c,d | 7.33 (2.83 to 19.67) | 10.00 (4.82 to 43.83) | 6.95 (2.67 to 18.08) | 0.011* | 10.89 (4.44 to 36.88) | 6.90 (2.67 to 18.50) | 0.026* |
| Mean serum albumin (SD), g/L c | 33.73 (3.94) | 31.12 (4.76) | 34.01 (3.74) | <0.001* | 32.50 (4.32) | 33.86 (3.88) | 0.045 |
| Mean total calcium (SD), mmol/L c | 2.20 (0.14) | 2.15 (0.13) | 2.20 (0.14) | 0.008* | 2.21 (0.12) | 2.20 (0.14) | 0.69 |
| Mean phosphate (SD), mmol/L c | 1.55 (0.38) | 1.64 (0.39) | 1.54 (0.38) | 0.135 | 1.59 (0.41) | 1.55 (0.38) | 0.53 |
| Median parathyroid hormone (SD), pmol/L c | 29.58 (18.04 to 45.84) | 28.03 (20.70 to 43.02) | 29.77 (17.38 to 46.25) | 0.83 | 28.52 (21.56 to 50.24) | 29.65 (17.38 to 45.43) | 0.54 |
| Mean glycated hemoglobin (SD), % c,d | 6.14 (1.31) | 6.89 (1.24) | 6.05 (1.29) | <0.001* | 6.98 (1.36) | 6.03 (1.27) | <0.001* |
| Median hemoglobin (IQR), g/L c | 111.33 (102.92 to 117.67) | 108.00 (99.50 to 115.83) | 111.67 (103.67 to 117.67) | 0.060 | 108.50 (99.25 to 115.25) | 111.67 (103.67 to 117.67) | 0.080 |
| Mean SF-36v2® PCS (SD) | 38.14 (10.70) | 33.08 (8.92) | 38.71 (10.74) | 0.001* | 33.16 (9.93) | 38.71 (10.65) | 0.001* |
| Mean SF-36v2® MCS (SD) | 48.55 (11.40) | 47.08 (13.96) | 48.71 (11.09) | 0.45 | 47.11 (13.56) | 48.71 (11.14) | 0.44 |
| Previous foot ulceration | 97 (21.6) | 32 (71.1) | 65 (16.0) | <0.001* | 44 (95.7) | 53 (13.1) | <0.001* |
| Current foot ulceration | 45 (10.0) | 45 (100.0) | N/A | N/A | 26 (56.5) | 19 (4.7) | <0.001* |
| Lower extremity amputation | 46 (10.2) | 26 (57.8) | 20 (4.9) | <0.001* | 46 (100) | N/A | N/A |
| Minor | 39 (8.7) | 22 (48.9) | 17 (4.2) | <0.001* | 39 (84.8) | ||
| Major | 12 (2.7) | 8 (17.8) | 4 (1.0) | <0.001* | 12 (26.1) | ||
| Combination | 5 (1.1) | 4 (8.9) | 1 (0.2) | <0.001* | 5 (10.9) | ||
*Significant difference between ‘foot ulceration/amputation’ and ‘no foot ulceration/amputation’ groups, p < 0.05. SD Standard deviation. a‘Ethnicity other’ were for participants that identified themselves as ‘Australian’ (excluding Indigenous Australians). ESRD End-stage renal disease. CAPD Continuous ambulatory peritoneal dialysis. APD Automated peritoneal dialysis. IQR Interquartile range. bKnown peripheral neuropathy/known peripheral arterial disease were defined as a history of peripheral neuropathy/peripheral arterial disease documented in the medical records. cAn average of the three latest laboratory test values was collected. dMaximum missing data were for glycated hemoglobin involving 39 participants overall (8.7%). Missing data were for glycated hemoglobin (n = 39) and C-reactive protein (n = 3). SF-36v2® = Short-Form-36 version 2.0. PCS Physical component score. MCS Mental component score. N/A Not applicable