Table 2 Baseline demographic and clinical characteristics stratified by quartiles of urine albumin-to-protein ratio (uAPR).

From: The ratio and difference of urine protein-to-creatinine ratio and albumin-to-creatinine ratio facilitate risk prediction of all-cause mortality

 Variable

Total (n = 2904)

uAPR ≦ 10.8 (n = 723)

10.8 < uAPR ≦ 30.0 (n = 737)

30.0 < uAPR ≦ 57.5 (n = 720)

uAPR > 57.5 (n = 724)

P-value†

P for trend‡

Age (year), median (IQR)

58.6 (45.4, 70.8)

53.7 (40.2, 66.3)

59.8 (46.8, 72.5)

61.9 (49.7, 73.8)

58.1 (45.5, 69.7)

< 0.001

< 0.001

Female, n (%)

1207 (41.6)

275 (38.0)

318 (43.2)

302 (41.9)

312 (43.1)

0.2

0.09

Body mass index (kg/m2), median (IQR)

24.1 (21.8, 27.3)

23.5 (21.3, 25.8)

23.9 (21.3, 26.7)

24.0 (21.8, 27.4)

24.8 (22.5, 28.3)

< 0.001

< 0.001

Follow-up duration (year), median (IQR)

3.32 (1.41, 6.28)

3.33 (1.44, 5.73)

3.47 (1.45, 6.65)

3.17 (1.27, 6.46)

3.25 (1.54, 6.01)

0.6

0.9

Baseline comorbidities, n (%)

CKD stage 1–2

1343 (47.3)

485 (69.8)

367 (51.4)

256 (36.0)

235 (32.7)

< 0.001

< 0.001

CKD stage 3–5

1495 (52.7)

210 (30.2)

347 (48.6)

455 (64.0)

483 (67.3)

  

Diabetes

928 (32.1)

144 (19.9)

226 (30.9)

269 (37.4)

289 (40.1)

< 0.001

< 0.001

Hypertension

1245 (43.0)

167 (23.1)

306 (41.9)

373 (51.8)

399 (55.3)

< 0.001

< 0.001

Cardiovascular disease

766 (26.5)

132 (18.3)

198 (27.1)

221 (30.8)

215 (29.8)

< 0.001

< 0.001

Cancer before enrollment

265 (9.1)

61 (8.4)

80 (10.9)

64 (8.9)

60 (8.3)

0.3

0.6

Cancer after enrollment

166 (5.7)

39 (5.4)

48 (6.5)

50 (6.9)

29 (4.0)

0.07

0.3

Cancer (before or after enrollment)

431 (14.8)

100 (13.8)

128 (17.4)

114 (15.8)

89 (12.3)

0.04

0.3

Baseline medication profiles, n (%)

Pentoxifylline

389 (14.8)

40 (6.6)

72 (10.7)

120 (17.9)

157 (23.3)

< 0.001

< 0.001

Dipyridamole

91 (3.5)

13 (2.1)

21 (3.1)

28 (4.2)

29 (4.3)

0.1

0.02

Anti-platelet agents

683 (26.0)

129 (21.2)

171 (25.3)

196 (29.3)

187 (27.8)

0.006

0.003

NSAIDs

721 (27.5)

190 (31.2)

212 (31.4)

176 (26.3)

143 (21.3)

< 0.001

< 0.001

Contrast

479 (18.2)

142 (23.3)

146 (21.6)

108 (16.1)

83 (12.3)

< 0.001

< 0.001

Antihypertension agents

ACEI

465 (17.7)

50 (8.2)

107 (15.9)

160 (23.9)

148 (22.0)

< 0.001

< 0.001

ARBs

919 (35.0)

108 (17.7)

217 (32.2)

267 (39.9)

327 (48.6)

< 0.001

< 0.001

Diuretics

1192 (45.4)

217 (35.6)

289 (42.8)

326 (48.7)

360 (53.5)

< 0.001

< 0.001

Antidiabetic agents

OAD

724 (27.6)

116 (19.1)

174 (25.8)

204 (30.5)

230 (34.2)

< 0.001

< 0.001

Insulin

539 (20.5)

81 (13.3)

131 (19.4)

169 (25.3)

158 (23.5)

< 0.001

< 0.001

Baseline biochemical profiles, median (IQR)

eGFR (mL/min/1.73m2)

56.8 (27.8, 91.8)

84.0 (53.0, 104.6)

62.0 (31.9, 94.0)

46.4 (19.7, 76.3)

40.9 (19.5, 71.7)

< 0.001

< 0.001

Serum creatinine (mg/dL)

1.23 (0.86, 2.16)

0.96 (0.77, 1.33)

1.16 (0.81, 1.88)

1.45 (1.00, 2.87)

1.59 (1.03, 2.91)

< 0.001

< 0.001

Blood urea nitrogen (mg/dL)

20.0 (13.0, 36.0)

15.0 (11.0, 21.0)

18.0 (12.0, 31.5)

24.0 (15.0, 44.0)

26.0 (16.0, 45.0)

< 0.001

< 0.001

Serum uric acid (mg/dL)

6.50 (5.20, 8.00)

5.80 (4.80, 7.10)

6.25 (4.90, 7.80)

6.60 (5.50, 8.00)

7.20 (6.00, 8.60)

< 0.001

< 0.001

Sodium (mmol/L)

138 (136, 140)

138 (135, 140)

138 (136, 140)

138 (135, 140)

138 (136, 139)

0.7

0.3

Potassium (mmol/L)

4.10 (3.70, 4.50)

4.00 (3.70, 4.30)

4.00 (3.70, 4.40)

4.10 (3.70, 4.50)

4.30 (3.80, 4.60)

< 0.001

< 0.001

Calcium (mg/dL)

8.70 (8.20, 9.20)

8.90 (8.30, 9.30)

8.80 (8.23, 9.20)

8.70 (8.20, 9.20)

8.70 (8.10, 9.10)

0.007

0.001

Phosphate (mg/dL)

4.00 (3.40, 4.80)

3.70 (3.05, 4.50)

3.70 (3.20, 4.50)

4.10 (3.60, 4.90)

4.30 (3.70, 5.10)

< 0.001

< 0.001

Serum albumin (g/dL)

4.00 (3.30, 4.40)

4.10 (3.50, 4.50)

4.10 (3.60, 4.40)

3.90 (3.20, 4.30)

3.70 (3.10, 4.10)

< 0.001

< 0.001

Hemoglobin (g/dL)

11.9 (9.8, 13.8)

12.5 (10.6, 14.1)

12.0 (10.1, 13.8)

10.9 (9.3, 13.3)

11.9 (9.8, 13.9)

< 0.001

< 0.001

Total cholesterol (mg/dL)

181 (152, 214)

176 (146, 210)

170 (144, 201)

179 (153, 207)

197 (165, 238)

< 0.001

< 0.001

Triglyceride (mg/dL)

129 (85, 195)

113 (74, 173)

124 (82, 178)

127 (85, 184)

152 (103, 231)

< 0.001

< 0.001

Glucose (mg/dL)

116 (99, 159)

112 (97, 154)

116 (99, 157)

119 (100, 168)

119 (98, 160)

0.05

0.05

Urine creatinine (mg/dL)

92.3 (59.4, 144.0)

121.3 (74.3, 169.8)

98.2 (63.3, 151.4)

83.8 (54.4, 127.6)

78.0 (53.0, 115.9)

< 0.001

< 0.001

uPCR (mg/g)

310 (101, 1,608)

89 (62, 162)

138 (87, 380)

458 (185, 1,733)

2416 (1,008, 5072)

< 0.001

< 0.001

uACR (mg/g)

86 (13, 757)

5 (3, 10)

28 (15, 76)

203 (83, 832)

1682 (697, 3474)

< 0.001

< 0.001

uAPR (%)

30.0 (10.8, 57.5)

6.0 (4.0, 8.2)

18.3 (14.4, 23.8)

45.7 (37.7, 52.6)

67.8 (62.9, 74.7)

< 0.001

< 0.001

uNAP (mg/g)

186 (80, 683)

83 (58, 156)

112 (69, 304)

249 (105, 931)

674 (280, 1556)

< 0.001

< 0.001

  1. ACEI angiotensin-converting-enzyme inhibitors, ARBs angiotensin receptor blockers, CKD chronic kidney disease, eGFR estimated glomerular filtration rate, NSAIDs nonsteroidal anti-inflammatory drugs, OAD oral antidiabetic agents, uPCR urine protein-to-creatinine ratio, uACR urine albumin-to-creatinine ratio, uAPR urine albumin-to-protein ratio, uNAP urine non-albumin proteinuria.
  2. †P-values are calculated by Kruskal–Wallis test for continuous variables and Chi-square test for categorical variables.
  3. ‡P-values for trend are calculated by Spearman's correlation for continuous variables and by Cochran-Armitage trend test for binary variables.
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