Table 2.
Baseline characteristics of patients with COPD exacerbation (n=36,107) and odds ratios for coexistence of AKI (n=704)
| Baseline patient characteristics | Total at baseline, n (%) | Concurrent AKI, n (%) | Crude odds ratio (95% CI) | P-valuea | Adjustedb odds ratio (95% CI) | P-valueb |
|---|---|---|---|---|---|---|
| Sex | ||||||
| Male | 19,235 (53.3) | 427 (2.2) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| Female | 16,872 (46.7) | 277 (1.6) | 0.74 (0.63, 0.86) | 0.68 (0.58, 0.80) | ||
| Age (years) | ||||||
| <50 | 1,547 (4.3) | 6 (0.4) | 1 (reference) | <0.001 | 1 (reference) | 0.066 |
| 50–59 | 4,989 (13.8) | 37 (0.7) | 1.92 (0.81, 4.56) | 1.55 (0.65, 3.71) | ||
| 60–69 | 10,404 (28.8) | 138 (1.3) | 3.45 (1.52, 7.83) | 1.93 (0.84, 4.45) | ||
| 70–79 | 12,496 (34.6) | 303 (2.4) | 6.38 (2.84, 14.3) | 2.28 (0.99, 5.25) | ||
| 80–89 | 6,151 (17.0) | 202 (3.3) | 8.72 (3.86, 19.68) | 2.37 (1.02, 5.50) | ||
| ≥90 | 520 (1.4) | 18 (3.5) | 9.21 (3.64, 23.33) | 1.88 (0.72, 4.93) | ||
| Region | ||||||
| London | 3,811 (10.6) | 88 (2.3) | 1 (reference) | 0.005 | 1 (reference) | 0.035 |
| Midlands | 5,453 (15.1) | 109 (2.0) | 0.86 (0.64, 1.15) | 0.84 (0.63, 1.13) | ||
| North England | 12,054 (33.4) | 193 (1.6) | 0.69 (0.53, 0.89) | 0.89 (0.70, 1.14) | ||
| South England | 14,789 (41.0) | 314 (2.1) | 0.92 (0.72, 1.17) | 0.71 (0.55, 0.92) | ||
| Comorbidities | ||||||
| Body mass index | ||||||
| Underweight | 1,418 (3.9) | 22 (1.6) | 0.94 (0.60, 1.46) | <0.001 | 1.18 (0.75, 1.86) | 0.002 |
| Normal | 14,296 (39.6) | 236 (1.7) | 1 (reference) | 1 (reference) | ||
| Overweight | 12,056 (33.4) | 221 (1.8) | 1.11 (0.92, 1.34) | 0.91 (0.76, 1.11) | ||
| Moderately obese | 4,893 (13.6) | 117 (2.4) | 1.46 (1.17, 1.83) | 1.23 (0.98, 1.55) | ||
| Severely obese | 1,345 (3.7) | 38 (2.8) | 1.73 (1.22, 2.45) | 1.51 (1.05, 2.17) | ||
| Morbidly obese | 643 (1.8) | 20 (3.1) | 1.91 (1.20, 3.04) | 2.13 (1.31, 3.46) | ||
| Missing | 1,456 (4.0) | 50 (3.4) | – | – | ||
| COPD severity (GOLD stage) | ||||||
| I | 3,669 (10.2) | 50 (1.4) | 1 (reference) | 0.239 | 1 (reference) | 0.292 |
| II | 13,690 (37.9) | 253 (1.9) | 1.36 (1.00, 1.85) | 1.34 (0.98, 1.83) | ||
| III | 9,473 (26.2) | 165 (1.7) | 1.28 (0.93, 1.76) | 1.26 (0.91, 1.75) | ||
| IV | 2,844 (7.9) | 50 (1.8) | 1.30 (0.87, 1.92) | 1.37 (0.91, 2.07) | ||
| Missing | 6,431 (17.8) | 186 (2.9) | – | – | ||
| Hypertension | 19,517 (54.1) | 480 (2.5) | 1.84 (1.57, 2.16) | <0.001 | 1.35 (1.14, 1.59) | <0.001 |
| Diabetes mellitus | 8,044 (22.3) | 193 (2.4) | 1.32 (1.12, 1.57) | 0.001 | 1.17 (0.98, 1.39) | 0.083 |
| Angina | 7,252 (20.1) | 137 (1.9) | 0.96 (0.80, 1.16) | 0.676 | 0.74 (0.61, 0.89) | 0.002 |
| Myocardial infarction | 5,382 (14.9) | 118 (2.2) | 1.15 (0.94, 1.41) | 0.163 | 0.85 (0.69, 1.05) | 0.125 |
| Atrial fibrillation | 7,028 (19.5) | 186 (2.7) | 1.50 (1.27, 1.78) | <0.001 | 1.08 (0.91, 1.29) | 0.382 |
| Heart failure | 7,645 (21.2) | 258 (3.4) | 2.19 (1.88, 2.56) | <0.001 | 1.27 (1.08, 1.50) | 0.004 |
| Coronary artery bypass graft | 1,557 (4.3) | 32 (2.1) | 1.06 (0.74, 1.51) | 0.758 | 0.82 (0.57, 1.19) | 0.304 |
| Pulmonary hypertension | 942 (2.6) | 23 (2.4) | 1.27 (0.83, 1.93) | 0.270 | 1.13 (0.73, 1.73) | 0.591 |
| CKD (eGFR mL/kg/1.73 m2) | ||||||
| ≥90 | 6,320 (17.5) | 35 (0.6) | 1 (reference) | <0.001 | 1 (reference) | <0.001 |
| 60–89 | 16,885 (46.8) | 145 (0.9) | 1.56 (1.07, 2.25) | 1.31 (0.89, 1.93) | ||
| 30–59 | 11,481 (31.8) | 341 (3.0) | 5.50 (3.88, 7.79) | 4.35 (2.96, 6.38) | ||
| 15–29 | 1,258 (3.5) | 128 (10.2) | 20.30 (13.92, 29.72) | 15.80 (10.40, 24.01) | ||
| <15 | 163 (0.5) | 55 (33.7) | 91.45 (57.47, 145.52) | 73.74 (44.97, 120.93) | ||
| Medications | ||||||
| COPD medications | 35,483 (98.3) | 679 (1.9) | 0.47 (0.31, 0.70) | <0.001 | 0.54 (0.36, 0.83) | 0.005 |
| Antiplatelets | 22,338 (61.9) | 480 (2.2) | 1.33 (1.13, 1.56) | 0.001 | 0.94 (0.79, 1.11) | 0.433 |
| Antidiabetes medications | 5,683 (15.7) | 153 (2.7) | 1.50 (1.25, 1.80) | <0.001 | 1.32 (1.09, 1.59) | 0.004 |
| Beta blockers | 11,746 (32.5) | 274 (2.3) | 1.33 (1.14, 1.55) | <0.001 | 1.09 (0.93, 1.27) | 0.304 |
| Diuretics | 25,821 (71.5) | 616 (2.4) | 2.83 (2.26, 3.55) | <0.001 | 1.59 (1.25, 2.01) | <0.001 |
| ACEi/ARB | 19,347 (53.6) | 468 (2.4) | 1.74 (1.48, 2.03) | <0.001 | 1.23 (1.05, 1.45) | 0.012 |
| Vasodilators | 1,730 (4.8) | 14 (0.8) | 0.40 (0.23, 0.68) | 0.001 | 0.53 (0.31, 0.91) | 0.021 |
| Alpha blockers | 1,768 (4.9) | 59 (3.3) | 1.80 (1.38, 2.36) | <0.001 | 1.20 (0.90, 1.59) | 0.218 |
| Inotropes | 5,417 (15.0) | 161 (3.0) | 1.70 (1.42, 2.03) | <0.001 | 1.19 (0.99, 1.43) | 0.068 |
| Nitrates | 7,115 (19.7) | 129 (1.8) | 0.78 (0.64, 0.96) | 0.021 | 0.77 (0.62, 0.95) | 0.016 |
| Calcium channel blockers | 13,405 (37.1) | 312 (2.3) | 1.29 (1.05, 1.57) | 0.013 | 1.31 (1.07, 1.61) | 0.010 |
| Antiarrhythmic | 2,625 (7.3) | 60 (2.3) | 1.19 (0.91, 1.56) | 0.197 | 0.85 (0.64, 1.11) | 0.230 |
| Anticoagulants | 6,976 (19.3) | 168 (2.4) | 1.32 (1.10, 1.57) | 0.002 | 1.03 (0.86, 1.23) | 0.768 |
| Lipid lowering | 20,962 (58.1) | 405 (1.9) | 0.98 (0.84, 1.14) | 0.775 | 1.01 (0.86, 1.17)** | 0.941 |
Notes:
a
Joint log likelihood test.
b
Adjusted for sex, age group, and eGFR.
**
Evidence of collinearity with eGFR, adjusted for age and sex only.
Abbreviations: COPD, chronic obstructive pulmonary disease; AKI, acute kidney injury; CI, confidence interval; GOLD, Global initiative for chronic Obstructive Lung Disease; CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; ACEi, angiotensin-converting enzyme inhibitors; ARB, angiotensin receptor blocker.