Table 1.
Baseline characteristics of all patients with COPD (n=189,561) and incidence AKI (n=1,610)
| Baseline patient characteristics | Total at baseline, n (%) | With AKI, n (rate/100,000 py) | Crude rate ratio of AKI (95% CI) | P-valuea | Adjustedb rate ratio of AKI (95% CI) | P-valuea |
|---|---|---|---|---|---|---|
| Sex | ||||||
| Male | 90,466 (47.7) | 926 (157) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| Female | 99,095 (52.3) | 684 (95) | 0.65 (0.59, 0.72) | 0.66 (0.60, 0.73) | ||
| Age (years) | ||||||
| <50 | 30,761 (16.2) | 30 (14) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| 50–59 | 37,538 (19.8) | 125 (38) | 3.27 (2.20, 4.88) | 3.19 (2.14, 4.75) | ||
| 60–69 | 49,422 (26.1) | 354 (102) | 7.43 (5.12, 10.79) | 7.14 (4.92, 10.37) | ||
| 70–79 | 46,174 (24.4) | 640 (219) | 15.84 (10.98, 22.84) | 15.30 (10.61, 22.06) | ||
| 80–89 | 22,822 (12.0) | 423 (368) | 26.68 (18.43, 38.64) | 26.42 (18.25, 38.27) | ||
| ≥90 | 2,844 (1.5) | 38 (380) | 27.52 (17.04, 44.41) | 28.66 (17.76, 46.27) | ||
| Region | ||||||
| London | 20,819 (11.0) | 199 (146) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| Midlands | 31,903 (16.8) | 236 (114) | 0.78 (0.64, 0.94) | 0.77 (0.64, 0.93) | ||
| North England | 51,093 (27.0) | 487 (142) | 0.97 (0.83, 1.15) | 1.02 (0.86, 1.20) | ||
| South England | 85,746 (45.2) | 688 (120) | 0.82 (0.70, 0.96) | 0.80 (0.68, 0.93) | ||
| Comorbidities | ||||||
| Body mass index | ||||||
| Underweight | 5,313 (2.8) | 33 (106) | 1.29 (0.91, 1.85) | <0.001 | 1.42 (0.99, 2.02) | <0.001 |
| Normal | 76,011 (40.1) | 418 (82) | 1 (reference) | 1 (reference) | ||
| Overweight | 64,683 (34.1) | 592 (134) | 1.63 (1.44, 1.85) | 1.43 (1.26, 1.63) | ||
| Moderately obese | 24,846 (13.1) | 299 (178) | 2.16 (1.87, 2.51) | 2.15 (1.85, 2.49) | ||
| Severely obese | 7,324 (3.9) | 123 (251) | 3.06 (2.50, 3.74) | 3.80 (3.10, 4.65) | ||
| Morbidly obese | 3,149 (1.7) | 55 (264) | 3.22 (2.43, 4.26) | 5.17 (3.89, 6.86) | ||
| Missing | 8,138 (4.3) | 90 (238) | – | – | ||
| COPD severity (GOLD stage) | ||||||
| I | 24,507 (12.9) | 145 (81) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| II | 53,697 (28.3) | 514 (138) | 1.70 (1.41, 2.04) | 1.42 (1.18, 1.71) | ||
| III | 26,626 (14.1) | 295 (172) | 2.12 (1.74, 2.59) | 1.55 (1.27, 1.90) | ||
| IV | 7,007 (3.7) | 51 (126) | 1.56 (1.13, 2.14) | 1.15 (0.84, 1.59) | ||
| Missing | 77,724 (41.0) | 605 (123) | ||||
| Hypertension | 89,824 (47.4) | 1,161 (191) | 2.75 (2.47, 3.07) | <0.001 | 1.89 (1.69, 2.11) | <0.001 |
| Diabetes mellitus | 33,042 (17.4) | 613 (272) | 2.82 (2.55, 3.12) | <0.001 | 2.50 (2.26, 2.77) | <0.001 |
| Angina | 25,291 (13.3) | 398 (226) | 2.26 (2.02, 2.53) | <0.001 | 1.48 (1.32, 1.66) | <0.001 |
| Myocardial infarction | 16,872 (8.9) | 333 (288) | 2.90 (2.57, 3.27) | <0.001 | 1.92 (1.70, 2.17) | <0.001 |
| Atrial fibrillation | 22,065 (11.6) | 457 (330) | 3.20 (2.87, 3.56) | <0.001 | 1.84 (1.64, 2.05) | <0.001 |
| Heart failure | 21,778 (11.5) | 652 (537) | 6.36 (5.76, 7.03) | <0.001 | 3.82 (3.44, 4.24) | <0.001 |
| Coronary artery bypass graft | 5,305 (2.8) | 130 (366) | 3.03 (2.53, 3.64) | <0.001 | 2.13 (1.78, 2.56) | <0.001 |
| Pulmonary hypertension | 1,963 (1.0) | 45 (416) | 3.31 (2.46, 4.46) | <0.001 | 2.37 (1.76, 3.18) | <0.001 |
| Kidney disease | ||||||
| CKD stage 3–4 | 35,090 (18.5) | 918 (370) | 8.95 (7.96, 10.06) | <0.001 | 5.90 (5.22, 6.67) | <0.001 |
| Renal diseasec | 4,835 (2.6) | 286 (1,081) | 26.16 (22.48, 30.43) | 19.67 (16.87, 22.92) | ||
| Medications | ||||||
| COPD medications | 160,121 (84.5) | 1,428 (135) | 1.51 (1.29, 1.76) | <0.001 | 1.38 (1.18, 1.61) | 0.001 |
| Antiplatelets | 105,831 (55.8) | 1,184 (215) | 3.59 (3.21, 4.01) | <0.001 | 2.08 (1.86, 2.34) | <0.001 |
| Antidiabetes medications | 23,591 (12.5) | 495 (311) | 3.06 (2.75, 3.40) | <0.001 | 2.85 (2.56, 3.17) | <0.001 |
| Beta blockers | 61,155 (32.3) | 787 (184) | 1.85 (1.68, 2.04) | <0.001 | 1.53 (1.39, 1.69) | <0.001 |
| Diuretics | 101,116 (53.3) | 1,437 (220) | 7.67 (6.55, 8.98) | <0.001 | 4.72 (4.00, 5.56) | <0.001 |
| ACEi/ARB | 79,359 (41.9) | 1,155 (217) | 3.46 (3.10, 3.86) | <0.001 | 2.37 (2.12, 2.65) | <0.001 |
| Vasodilators | 11,292 (6.0) | 43 (53) | 0.40 (0.29, 0.54) | <0.001 | 0.53 (0.39, 0.71) | <0.001 |
| Alpha blockers | 7,338 (3.9) | 167 (342) | 2.87 (2.44, 3.36) | <0.001 | 2.00 (1.71, 2.35) | <0.001 |
| Inotropes | 15,477 (8.2) | 398 (444) | 4.27 (3.82, 4.79) | <0.001 | 2.40 (2.14, 2.70) | <0.001 |
| Nitrates | 26,114 (13.8) | 395 (236) | 2.12 (1.89, 2.38) | <0.001 | 1.59 (1.41, 1.78) | 0.002 |
| Calcium channel blockers | 58,611 (30.9) | 745 (184) | 1.81 (1.64, 2.00) | <0.001 | 1.36 (1.24, 1.51) | 0.001 |
| Antiarrhythmic | 7,633 (4.0) | 182 (384) | 3.25 (2.79, 3.80) | <0.001 | 2.18 (1.87, 2.55) | <0.001 |
| Anticoagulants | 21,977 (11.6) | 454 (318) | 3.07 (2.75, 3.42) | <0.001 | 2.05 (1.84, 2.29) | <0.001 |
| Lipid lowering | 87,747 (46.2) | 1,067 (175) | 2.09 (1.88, 2.32) | <0.001 | 1.64 (1.47, 1.82) | <0.001 |
Notes:
a
Adjusted for sex and age group.
b
Joint log likelihood test.
c
Renal disease as defined by microalbuminuria, proteinuria, or previous AKI admission.
Abbreviations: COPD, chronic obstructive pulmonary disease; AKI, acute kidney injury; py, person-years; CI, confidence interval; GOLD, Global initiative for chronic Obstructive Lung Disease; CKD, chronic kidney disease; ACEi, angiotensin-converting enzyme inhibitors; ARB, angiotensin II receptor blocker.