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Table 2 Baseline characteristics by chronic kidney disease (CKD) status

From: Hospitalisation events in people with chronic kidney disease as a component of multimorbidity: parallel cohort studies in research and routine care settings

  UK Biobank SAIL
No CKD
n = 458 572 (97.7%)
CKD
n = 10 767 (2.3%)
P value No CKD
n = 1 447 102 (89.3%)
CKD
n = 173 388 (10.7%)
P value
Age (years) Median (IQR) 58 (50 to 63) 64 (60 to 67) < 0.001 50 (36 to 63) 79 (72 to 85) < 0.001
Sex (%) Female 248,751 (54.2) 5746 (53.4) 0.072 788,725 (54.5) 98,782 (57.0) < 0.001
Male 209,821 (45.8) 5021 (46.6) 658,377 (45.5) 74,606 (43.0)
Ethnicity (%) White 432,151 (94.7) 10,202 (95.3) 0.008 622,324 (94.5) 71,424 (98.6) < 0.001
Black 7173 (1.6) 128 (1.2) 6032 (0.9) 129 (0.2)
Asian 10,311 (2.3) 235 (2.2) 16,499 (2.5) 335 (0.7)
Mixed 2705 (0.6) 48 (0.4) 3806 (0.6) 105 (0.1)
Other 4085 (0.9) 96 (0.9) 10,061 (1.5) 222 (0.3)
Missing values 2205 (0.5%) 889,353 (54.9)
Deprivation scorea Median (IQR) − 2.2 (− 3.7 to 0.5) − 2.0 (− 3.5 to 0.9) < 0.001 18.0 (10.8 to 30.0) 17.6 (11.0 to 28.3) < 0.001
Missing values 577 (0.1 %) 302,952 (18.7%)
Smoking status (%) Never 250,304 (54.9) 5261 (49.3) < 0.001 516,728 (48.4) 65,132 (47.4) < 0.001
Previous 157,573 (34.5) 4558 (42.7) 273,908 (25.7) 58,190 (42.4)
Current 48,402 (10.6) 862 (8.1) 276,545 (25.9) 13,962 (10.2)
Missing values 2379 (0.5%) 416,025 (25.7%)
Body mass index (kg/m2) Median (IQR) 27 (24 to 30) 29 (26 to 32) < 0.001 29 (24 to 33) 29 (25 to 32) 0.394
Missing values 1 873 (0.4%) 1 472 240 (90.9%)
Systolic blood pressure (mmHg) Median (IQR) 136 (125 to 150) 139 (127 to 152) < 0.001 130 (120 to 141) 134 (122 to 144) < 0.001
Missing values 14 639 (3.1%) 287 529 (17.7%)
Estimated glomerular filtration rate (ml/min/1.73m2) Median (IQR) 93.1 (83.8 to 100.2) 54. 1 (48.1 to 57.6) < 0.001 97.1 (85.4 to 109.4) 51.2 (42.9 to 56.2) < 0.001
Urine albumin-creatinine ratio (mg/mmol) Median (IQR) 0.0 (0.0 to 0.6) 0.4 (0.0 to 1.9) < 0.001 0.9 (0.5 to 2.1) 1.8 (0.8 to 5.7) < 0.001
Missing values 13,406 (2.9%) 1,453,186 (89.7%)
Long-term condition count (excluding CKD) Median (IQR) 1 (0 to 2) 2 (1 to 3) < 0.001 1 (0 to 2) 4 (2 to 5) < 0.001
  1. Interquartile range (IQR). P values: Kruskal-Wallis test for continuous variables and chi-squared tests for categorical variables
  2. aTownsend score for UK Biobank: higher scores suggest higher levels of deprivation. Welsh Index of Multiple Deprivation Rank for SAIL: lower ranks suggest higher levels of deprivation