Table 1

Characteristics of study participants by levels of solutes
Characteristic Overall P-cresol sulfate (mg/dl) Indoxyl sulfate (mg/dl) Monomethylamine (μg/l) Dimethlyamine (μM)
Low High Low High Low High Low High
0.0-3.l 3.1-11.1 0-1.6 1.6-6.8 24.2-49.6 49.7-190.6 7.6-18.3 18.3-33.9
N (%) 521 (100%) 261 (50.1) 260 (49.9) 261 (50.1) 260 (49.9) 262 (50.3) 259 (49.7) 263 (50.5) 258 (49.5)
Demographics
Mean age (SD) 58.3 (14.7) 56.6 (14.2)* 59.9 (14.9)* 57.3 (13.9) 59.2 (15.3) 56.9 (15.2)* 59.6 (14.0)* 58.6 (14.9) 57.9 (14.4)
% white 61.0 61.7 60.4 59.0 63.1 63.4 58.7 63.5 58.5
% male 54.1 47.1* 61.2* 54.4 53.9 50.0 58.3 53.6 54.7
Clinical
% ICED = 3 29.2 31.4 26.9 35.6* 22.7* 27.1 31.3 26.2 32.2
Mean BMI (SD) 27.4 (7.0) 28.3 (7.4)* 26.5 (6.5)* 27.7 (7.3) 27.1 (6.6) 27.5 (7.7) 27.3 (6.2) 27.1 (7.4) 27.8 (6.5)
% with residual urine output at 1 year 38.9 41.4 36.6 42.9 35.2 37.4 40.4 42.3 35.6
Mean KtV (SD) 1.27 1.26 1.29 1.24* 1.31* 1.27 1.27 1.27 1.27
Cause of ESRD
 Diabetes mellitus 47.8 50.2* 45.4* 56.7** 38.9** 49.2 46.3 46.4 49.2
 Hypertension 18.2 13.0* 23.5* 14.9** 21.5** 16.0 20.5 19.4 17.1
 Glomerulonephritis 16.1 18.4* 13.9* 10.3** 21.9** 14.5 17.8 15.2 17.1
 Other 17.9 18.4* 17.3* 18.0** 17.7** 20.2 15.4 15.2 17.1
% with diabetes 54.9 56.7 53.1 63.2** 46.5** 55.7 54.1 53.6 56.2
% with hypertension 97.0 96.5 97.6 96.6 97.5 97.5 96.6 96.5 97.6
% with gastrointestinal disease 41.8 44.8 38.9 43.3 40.4 39.7 44.0 42.6 41.1
Laboratory
Mean albumin (SD) 3.6 (0.4) 3.6 (0.4)* 3.7 (0.3)* 3.6 (0.4)** 3.7 (0.3)** 3.6 (0.4)* 3.7 (0.3)* 3.7 (0.3) 3.6 (0.4)
Mean creatinine (SD) 7.3 (2.4) 7.1 (2.5) 7.5 (2.3) 6.5 (2.1)** 8.1 (2.5)** 6.9 (2.4)** 7.8 (2.4)** 6.9 (2.4)** 7.7 (2.4)**
Median CRP (IQR) 0.4 (0.2-1.1) 0.4 (0.2-1.5)* 0.4 (0.2-0.8)* 0.5 (0.2-1.2) 0.4 (0.2-1.0) 0.4 (0.2-1.2) 0.4 (0.2-1.0) 0.4 (0.2-1.3) 0.4 (0.2-1.0)

Low, below population median value for solute; high, at or above population median values for solute. Diabetes, hypertension, and gastrointestinal disease were defined by domains of the index of disease severity scale of the ICED. n = 521 for all variables except BMI (n = 492), albumin (n = 515), creatinine (n = 516), CRP (n = 517), Kt/V (n = 401) and residual urine output at 1 year (n = 447).

*P < 0.05 for high vs. low level of solute, by ANOVA or χ2 test.

**P < 0.001 for high vs. low level of solute, by ANOVA or χ2 test.

Melamed et al.

Melamed et al. BMC Nephrology 2013 14:134   doi:10.1186/1471-2369-14-134

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