Baseline characteristics of matched patients with and without CKD (stages 3–5) by CKD status and stage
| Variables | By CKD status (n=468 399) | By CKD stage (n=235 004) | ||||
| Matched patients without known CKD (n=233 395) | Matched patients with CKD (n=235 004) | P value | CKD stage 3a (n=168 154) | CKD stage 3b (n=53 285) | CKD stage 4/5 (n=13 565) | |
| N (%) | N (%) | N (%) | N (%) | N (%) | ||
| Age (mean±SD) | 75.0±9.6 | 75.1±9.7 | <0.001 | 74.1±9.3 | 77.8±9.6 | 76.9±12.4 |
| Sex (male) | 93 050 (39.9) | 93 233 (39.7) | 0.173 | 67 470 (40.1) | 19 915 (37.4) | 5848 (43.1) |
| Ethnicity | <0.001 | |||||
| White/Non-recorded | 229 666 (98.4) | 230 906 (98.3) | 165 254 (98.3) | 52 439 (98.4) | 13 213 (97.4) | |
| South Asian | 1772 (0.8) | 2260 (1.0) | 1625 (1.0) | 464 (0.9) | 171 (1.3) | |
| Black | 1119 (0.5) | 1031 (0.4) | 710 (0.4) | 200 (0.4) | 121 (0.9) | |
| Others/Mixed | 838 (0.4) | 807 (0.3) | 565 (0.3) | 182 (0.3) | 60 (0.4) | |
| Socioeconomic status | <0.001 | |||||
| Q1 (least deprived) | 54 606 (23.4) | 51 402 (21.9) | 37 868 (22.5) | 10 949 (20.6) | 2585 (19.1) | |
| Q2 | 59 494 (25.5) | 58 693 (25.0) | 42 482 (25.3) | 13 081 (24.6) | 3130 (23.1) | |
| Q3 | 48 486 (20.8) | 49 038 (20.9) | 34 908 (20.8) | 11 202 (21.0) | 2928 (21.6) | |
| Q4 | 40 785 (17.5) | 43 396 (18.5) | 30 561 (18.2) | 10 104 (19.0) | 2731 (20.1) | |
| Q5 (most deprived) | 30 024 (12.9) | 32 475 (13.8) | 22 335 (13.3) | 7949 (14.9) | 2191 (16.2) | |
| Smoking status | <0.001 | |||||
| Non-smoker | 87 595 (37.5) | 77 333 (32.9) | 54 547 (32.4) | 18 137 (34.0) | 4649 (34.3) | |
| Current smoker | 35 633 (15.3) | 28 623 (12.2) | 20 212 (12.0) | 6609 (12.4) | 1802 (13.3) | |
| Ex-smoker | 104 637 (44.8) | 128 310 (54.6) | 93 074 (55.4) | 28 283 (53.1) | 6953 (51.3) | |
| Missing | 5530 (2.4) | 738 (0.3) | 321 (0.2) | 256 (0.5) | 161 (1.2) | |
| Body mass index | <0.001 | |||||
| <18.5 | 6012 (2.6) | 4189 (1.8) | 2653 (1.6) | 1194 (2.2) | 342 (2.5) | |
| 18.5–25 | 82 612 (35.4) | 67 768 (28.8) | 47 868 (28.5) | 15 846 (29.7) | 4054 (29.9) | |
| 25–30 | 78 723 (33.7) | 86 089 (36.6) | 63 606 (37.8) | 18 297 (34.3) | 4186 (30.9) | |
| >30 | 39 753 (17.0) | 62 361 (26.5) | 45 974 (27.3) | 13 198 (24.8) | 3189 (23.5) | |
| Missing | 26 295 (11.3) | 14 597 (6.2) | 8053 (4.8) | 4750 (8.9) | 1794 (13.2) | |
| Comorbidities | ||||||
| Asthma | 27 295 (11.7) | 30 586 (13.0) | <0.001 | 22 204 (13.2) | 6705 (12.6) | 1677 (12.4) |
| COPD | 14 520 (6.2) | 17 740 (7.6) | <0.001 | 12 019 (7.2) | 4554 (8.6) | 1167 (8.6) |
| Diabetes mellitus | 23 494 (10.1) | 51 442 (21.9) | <0.001 | 35 699 (21.2) | 12 145 (22.8) | 3598 (26.5) |
| Severe mental illness | 2808 (1.2) | 4281 (1.8) | <0.001 | 3070 (1.8) | 950 (1.8) | 261 (1.9) |
| Epilepsy | 3596 (1.5) | 3459 (1.5) | 0.053 | 2456 (1.5) | 787 (1.5) | 216 (1.6) |
| Depression | 36 309 (15.6) | 44 243 (18.8) | <0.001 | 32 224 (19.2) | 9718 (18.2) | 2301 (17.0) |
| Coronary artery disease | 26 875 (11.5) | 52 603 (22.4) | <0.001 | 35 485 (21.1) | 13 471 (25.3) | 3647 (26.9) |
| Heart failure | 7151 (3.1) | 22 976 (9.8) | <0.001 | 12 167 (7.2) | 7887 (14.8) | 2922 (21.5) |
| Peripheral arterial disease | 7236 (3.1) | 14 440 (6.1) | <0.001 | 8950 (5.3) | 4191 (7.9) | 1299 (9.6) |
| Stroke or TIA | 11 017 (4.7) | 18 665 (7.9) | <0.001 | 12 075 (7.2) | 5095 (9.6) | 1495 (11.0) |
| Atrial fibrillation | 14 556 (6.2) | 28 345 (12.1) | <0.001 | 18 411 (11.0) | 7908 (14.8) | 2026 (14.9) |
| Hypertension | 123 843 (53.1) | 198 199 (84.3) | <0.001 | 137 848 (82.0) | 47 839 (89.8) | 12 512 (92.2) |
| Rheumatoid arthritis | 4129 (1.8) | 5874 (2.5) | <0.001 | 4139 (2.5) | 1386 (2.6) | 349 (2.6) |
| Osteoporosis | 15 551 (6.7) | 15 873 (6.8) | 0.211 | 11 169 (6.6) | 3817 (7.2) | 887 (6.5) |
| Hypothyroidism | 16 608 (7.1) | 28 224 (12.0) | <0.001 | 19 859 (11.8) | 6709 (12.6) | 1656 (12.2) |
| Cancer | 45 567 (19.5) | 52 774 (22.5) | <0.001 | 36 339 (21.6) | 12 939 (24.3) | 3496 (25.8) |
CKD, chronic kidney disease; COPD, chronic obstructive pulmonary disease; TIA, transient ischaemic attack.