Clinical characteristics of the patients at biopsy diagnosis
| Variables | Total (n=6426) | Hokkaido (n=148) | Tohoku (n=911) | Kanto (n=1229) | Koshinetsu (n=201) | Hokuriku (n=258) | Tokai (n=1432) | Kinki (n=706) | Chugoku (n=485) | Shikoku (n=183) | Kyushu (n=873) | P values | Maximal fold among regions |
| Age, mean (SD), years | 39.5 (17.7) | 41.5 (16.6) | 42.5 (18.1) | 34.7 (17.5) | 39.2 (14.9) | 42.2 (16.8) | 41.4 (16.6) | 38.9 (17.1) | 39.4 (17.8) | 32.2 (20.2) | 40.8 (18.3) | <0.001 | 1.32 |
| Male, n (%) | 3297 (51.3) | 78 (52.7) | 488 (53.6) | 652 (53.1) | 96 (47.8) | 143 (55.4) | 707 (49.4) | 367 (52.0) | 255 (52.6) | 86 (47.0) | 425 (48.7) | 0.182 | 1.18 |
| BMI mean (SD), kg/m2 | 22.6 (4.0) | 23.4 (4.2) | 23.5 (4.2) | 22.0 (4.2) | 22.2 (3.7) | 22.8 (3.6) | 22.6 (3.7) | 22.4 (4.1) | 22.7 (4.2) | 21.7 (4.0) | 22.7 (4.0) | <0.001 | 1.08 |
| SBP, mean (SD), mm Hg | 124 (18) | 126 (19) | 126 (17) | 120 (18) | 120 (16) | 122 (17) | 127 (18) | 122 (18) | 124 (18) | 117 (16) | 126 (19) | <0.001 | 1.09 |
| DBP, mean (SD), mm Hg | 74 (13) | 76 (13) | 76 (13) | 72 (13) | 75 (13) | 74 (13) | 76 (13) | 73 (12) | 74 (13) | 69 (12) | 75 (13) | <0.001 | 1.10 |
| Hypertension, n (%) | 2790 (43.4) | 82 (55.4) | 403 (44.2) | 457 (37.2) | 93 (46.3) | 127 (49.2) | 709 (49.5) | 279 (39.5) | 203 (41.9) | 49 (26.8) | 388 (44.4) | <0.001 | 2.07 |
| eGFR, mean (SD), mL/min/1.73 m2 | 74.4 (30.3) | 67.5 (31.3) | 73.3 (29.6) | 79.6 (31.5) | 71.3 (27.7) | 73.2 (27.0) | 69.0 (27.8) | 74.8 (29.3) | 78.0 (30.9) | 91.4 (35.2) | 73.5 (31.2) | <0.001 | 1.35 |
| Serum albumin, mean (SD), g/dL | 3.9 (0.6) | 3.7 (0.7) | 4.0 (0.7) | 4.0 (0.6) | 4.0 (0.7) | 3.8 (1.0) | 3.9 (0.6) | 3.9 (0.6) | 4.0 (0.6) | 4.0 (0.6) | 3.9 (0.6) | <0.001 | 1.08 |
| Total cholesterol, mean (SD), mg/dL | 194 (59) | 198 (45) | 182 (68) | 186 (71) | 188 (71) | 198 (60) | 204 (47) | 199 (49) | 197 (47) | 189 (55) | 198 (59) | <0.001 | 1.12 |
| UPE, mean (SD), g/day | 1.16 (1.62) | 1.93 (2.63) | 1.00 (1.55) | 0.97 (1.25) | 0.93 (1.22) | 1.00 (1.23) | 1.42 (1.72) | 1.04 (1.46) | 0.97 (1.43) | 1.08 (2.31) | 1.35 (1.83) | <0.001 | 2.08 |
| Haematuria grade 2/3, n (%) | 4313 (67.1) | 101 (68.2) | 598 (65.6) | 801 (65.2) | 142 (70.6) | 170 (65.9) | 1024 (71.5) | 454 (64.3) | 327 (67.4) | 94 (51.4) | 602 (69.0) | <0.001 | 1.39 |
| KDIGO prognosis risk of CKD, n (%) | |||||||||||||
| Very high risk | 1813 (28.2) | 59 (39.9) | 265 (29.1) | 289 (23.5) | 61 (30.3) | 64 (24.8) | 495 (34.6) | 175 (24.8) | 117 (24.1) | 20 (10.9) | 268 (30.7) | <0.001 | 3.66 |
| High risk | 2353 (36.6) | 48 (32.4) | 272 (29.9) | 446 (36.3) | 66 (32.8) | 100 (38.8) | 623 (43.5) | 248 (35.1) | 157 (32.4) | 66 (36.1) | 327 (37.5) | <0.001 | 1.45 |
| Moderately increased risk | 1412 (22.0) | 24 (16.2) | 199 (21.8) | 322 (26.2) | 53 (26.4) | 54 (20.9) | 228 (15.9) | 183 (25.9) | 122 (25.2) | 43 (23.5) | 184 (21.1) | <0.001 | 1.66 |
| Low risk | 849 (13.2) | 17 (11.5) | 175 (19.2) | 172 (14.0) | 21 (10.4) | 40 (15.5) | 86 (6.0) | 100 (14.2) | 89 (18.4) | 54 (29.5) | 94 (10.8) | <0.001 | 4.92 |
BMI, body mass index; CKD, chronic kidney disease; DBP, diastolic blood pressure; eGFR, estimated glomerular filtration rate; KDIGO, Kidney Disease Improving Global Outcomes; SBP, systolic blood pressure; UPE, urinary protein excretion.