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Table 1 Characteristics of the overall sample and subgroups defined by KI values

From: A low fractional excretion of Phosphate/Fgf23 ratio is associated with severe abdominal Aortic calcification in stage 3 and 4 kidney disease patients

  Overall sample Subgroups defined by Kauppila Index  
Characteristics (n = 178) KI = 0 (n = 57) KI 1–5 (n = 68) KI > 5 (n = 53) P value
Female 37.6 (67) 52.6 (30) 29.4 (20) 32.1 (17) 0.017
Age 69.1 ± 11.6 61 ± 14 71 ± 8 75 ± 6 0.001
BMI (Kg/m2) 28.5 ± 5.2 28.2 ± 6.1 29.2 ± 4.5 27.9 ± 4.9 0.342
Systolic BP (mmHg) 138.9 ± 21.2 134 ± 22 142 ± 19 140 ± 22 0.118
Diastolic BP (mmHg) 72.6 ± 10.9 74 ± 10 73 ± 11 70 ± 12 0.123
Pulse pressure (mmHg) 66.3 ± 19.9 60 ± 21 69 ± 19 70 ± 19 0.011
CKD Stage      0.169
CKD 3 33.7 (60) 42.1 (24) 35.3 (24) 22.6 (12)  
CKD 4 66.3 (118) 57.9 (33) 64.7 (44) 77.4 (41)  
Other conditions      
Smokers 38.8 (69) 24.6 (14) 41.2 (28) 50.9 (27) 0.015
Diabetes mellitus 36.0 (64) 26.3 (15) 41.2 (28) 39.6 (21) 0.179
Hypertension 95.5 (170) 96.5 (55) 92.6 (63) 98.1 (52) 0.392
Etiology of CKD      0.011
Diabetic nephropathy 18.0 (32) 14 (8) 19.1 (13) 20.8 (11)  
Nephrosclerosis 32.6 (58) 19.3 (11) 38.2 (26) 39.6 (21)  
Chronic pyelonephritis 18.0 (32) 17.5 (10) 25 (17) 9.4 (5)  
Unknown 15.2 (27) 22.8 (13) 10.3 (7) 13.2 (7)  
Other 16.3 (29) 26.3 (15) 7.4 (5) 17 (9)  
History of CD 38.8 (69) 17.5 (10) 42.6 (29) 56.6 (30) 0.001
Cardiac ischemia 11.2 (20) 5.3 (3) 13.2 (9) 15.1 (8) 0.212
CHF 23.0 (41) 7 (4) 26.5 (18) 35.8 (19) 0.001
Stroke 9.1 (16) 5.4 (3) 10.3 (7) 11.5 (6) 0.513
Peripheral vascular disease 16.9 (30) 12.3 (7) 17.6 (12) 20.8 (11) 0.482
ABI 0.92 ± 0.25 0.95 ± 0.2 0.91 ± 0.20 0.91 ± 0.33 0.552
ABI <0.9 37.6 (67) 28.1 (16) 42.6 (29) 41.5 (22) 0.193
Carotid ultrasound      
IMT 0.83 ± 0.17 0.72 ± 0.14 0.86 ± 0.15 0.91 ± 0.18 0.001
Carotid plaque 73.6 (131) 45.6 (26) 82.4 (56) 92.5 (4950) 0.001
Atherosclerosis score      0.001
AS0/AS1 25.8 (46) 54.4 (31) 16.2 (11) 7.5 (4)  
AS2 53.9 (96) 33.3 (19) 58.8 (40) 69.8 (37)  
AS3 20.2 (36) 12.3 (7) 25 (17) 22.6 (12)  
Laboratory data      
Glucose (mg/dl) 112.7 ± 39.1 107 ± 32 118 ± 45 111 ± 37 0.283
Cholesterol (mg/dl 166.2 ± 30.9 171 ± 31 161 ± 32 168 ± 29 0.164
Albumin (g/dl) 4.3 ± 0.3 4.3 ± 0.4 4.3 ± 0.2 4.3 ± 0.2 0.629
CRP (mg/L) 5.2 ± 6.7 4.7 ± 5.3 4.8 ± 4.8 6.1 ± 9.7 0.468
Serum creatinine (mg/dl) 2.5 ± 0.7 2.5 ± 0.8 2.5 ± 0.7 2.6 ± 0.7 0.731
eGFR (ml/min) 27.2 ± 9.6 27.5 ± 9.9 28.2 ± 10.4 25.5 ± 7.9 0.309
Calcium (mg/dl) 9.2 ± 0.47 9.3 ± 0.46 9.2 ± 0.51 9.2 ± 0.41 0.311
Phosphate (mg/dl) 3.8 ± 0.6 3.9 ± 0.8 3.7 ± 0.5 3.8 ± 0.6 0.090
CaxP product (mg 2 /dl 2 ) 34.8 ± 6.0 36.4 ± 7.3 33.6 ± 4.7 34.6 ± 5.5 0.036
Bone ALP (ug/L) 18.5 ± 9.7 17.4 ± 6.2 18.2 ± 9.0 20.1 ± 12.9 0.336
PTH(i) (pmol/L) 15.6 ± 9.9 16.2 ± 10.1 14.8 ± 9.9 15.9 ± 9.9 0.711
25(OH)vitamin D (ng/ml) 22.6 ± 13.6 23.5 ± 17.6 22.6 ± 12.7 21.5 ± 9.1 0.898
1.25(OH) 2 vitamin D (pg/ml) 16.5 ± 10.4 15.7 ± 8.8 17.6 ± 12.7 15.9 ± 8.4 0.509
FEP (%) 35.8 ± 11.0 35.6 ± 11.4 36.2 ± 10.7 35.6 ± 11.2 0.931
FENa (%) 2.4 ± 1.1 2.4 ± 1.1 2.3 ± 0.9 2.6 ± 1.3 0.357
FECa (%) 0.95 ± 0.8 0.96 ± 0.9 0.99 ± 0.9 0.89 ± 0.5 0.790
FGF23 (RU/ml) 153.8 ± 111.5 136.1 ± 72.1 130.8 ± 81.9 202.4 ± 156.9 0.001
Soluble α-klotho (pg/ml) 482.2 ± 223.1 491 ± 250 466 ± 193 493 ± 230 0.739
Protein Intake (gr/Kg/day) 1.01 ± 0.27 1.01 ± 0.27 1.02 ± 0.28 1.02 ± 0.28 0.977
Medication      
Calcium-containing P binders 12.9 (23) 19.3 (11) 8.8 (6) 11.3 (6) 0.202
Oral vitamin D3 39.3 (70) 36.8 (21) 45.6 (31) 34 (18) 0.386
Oral active vitamin D 4.5 (8) 5.3 (3) 5.9 (4) 1.9 (1) 0.659
Antiplatelet 48.3 (86) 31.6 (18) 50 (34) 64.2 (34) 0.002
Statins 70.8 (126) 59.6 (34) 76.5 (52) 75.5 (40) 0.080
Diuretics 64.6 (115) 56.1 (32) 60.3 (41) 79.2 (42) 0.025
Loop diuretics 77.3 (85) 67.7 (21) 79.5 (31) 82.5 (33) 0.311
  1. Data are presented as % (n) = Percentage (number of patients) or Mean ± SD; P values were determined by Chi squared tests (or Fisher exact test in case of expected frequencies lower than 5) for comparison of frequencies, and Kruskal Wallis tests for quantitative variables. Abbreviations: KI, Kauppila Index; BMI, Body mass index; BP, Blood pressure; CD, Cardiovascular disease; CHF, Cardiac heart failure; ABI, Ankle, brachial index; IMT, Intima-media thickness; CRP, C reactive protein; eGFR, Estimated GFR; Bone Alp, Bone alkaline phosphatase; FEP, FECa and FENa indicate fractional excretion of phosphate, calcium and sodium, respectively; AS, Atherosclerosis score.