Table 1.
Baseline characteristics of kidney transplant recipients (KTR) across tertiles of N1-MN + 2Py excretion stratified by sex 1,2.
| Variable | Sex-Stratified Tertiles of N1-MN + 2Py Excretion | Std. β | p-Value | ||
|---|---|---|---|---|---|
| T1 n = 219 | T2 n = 221 | T3 n = 220 | |||
| Males, μmol/day | <181.3 | 181.3–261.2 | >261.2 | - | - |
| Females, μmol/day | <147.7 | 147.7–216.9 | >216.9 | - | - |
| Demographics | |||||
| Male, n (%) | 126 (58) | 127 (58) | 126 (57) | - | - |
| Age, years | 54.3 ± 12.6 | 52.3 ± 13.4 | 52.4 ± 12.1 | −0.10 | 0.01 |
| BMI, kg/m2 | 25.4 ± 4.5 | 26.7 ± 4.5 | 27.8 ± 5.1 | 0.19 | <0.001 |
| Body surface area, m2 | 1.9 ± 0.2 | 1.9 ± 0.2 | 2.0 ± 0.2 | 0.28 | <0.001 |
| Current smoker, n (%) | 24 (12) | 24 (12) | 30 (15) | 0.04 | 0.34 |
| Alcohol consumption, g/day | 1.0 (0.0–7.8) | 3.2 (0.1–12.0) | 5.1 (0.2–17.7) | 0.18 | <0.001 |
| Nutrition | |||||
| Energy intake, kcal/day | 2098 ± 619 | 2248 ± 718 | 2198 ± 576 | 0.06 | 0.17 |
| Plasma vitamin B6, nmol/L | 27.0 (15.0–41.0) | 26.0 (17.0–42.0) | 41.0 (22.0–66.0) | 0.30 | <0.001 |
| Glucose homeostasis | |||||
| Glucose, mmol/L | 5.2 (4.8–5.7) | 5.3 (4.8–6.0) | 5.3 (4.8–6.2) | 0.08 | 0.05 |
| HbA1c, (%) | 5.8 (5.5–6.1) | 5.8 (5.5–6.2) | 5.8 (5.5–6.3) | −0.003 | 0.95 |
| Diabetes, n (%) | 46 (21) | 51 (23) | 55 (25) | 0.05 | 0.23 |
| Antidiabetic, n (%) | 32 (15) | 34 (15) | 30 (14) | 0.007 | 0.86 |
| Lipid homeostasis | |||||
| Total cholesterol, mmol/L | 5.2 ± 1.2 | 5.1 ± 1.1 | 5.0 ± 1.1 | −0.03 | 0.40 |
| LDL, mmol/L | 3.0 ± 1.0 | 3.0 ± 0.9 | 3.0 ± 0.9 | 0.009 | 0.82 |
| HDL, mmol/L | 1.3 (1.1–1.7) | 1.3 (1.1–1.6) | 1.3 (1.1–1.6) | 0.05 | 0.23 |
| Triglycerides, mmol/L | 1.6 (1.2–2.3) | 1.7 (1.3–2.3) | 1.6 (1.2–2.2) | −0.03 | 0.39 |
| Statin, n (%) | 111 (51) | 122 (55) | 116 (53) | −0.02 | 0.61 |
| Hemodynamic | |||||
| Systolic blood pressure, mmHg | 138 ± 18 | 135 ± 16 | 135 ±17 | −0.08 | 0.05 |
| Diastolic blood pressure, mmHg | 82 ± 12 | 82 ± 11 | 83 ± 11 | 0.01 | 0.72 |
| Mean arterial pressure, mmHg | 108 ± 16 | 107 ± 14 | 107 ± 15 | −0.05 | 0.22 |
| Heart rate, beats per minute | 68 ± 12 | 69 ± 13 | 68 ± 12 | −0.006 | 0.87 |
| Antihypertensive use, n (%) | 196 (90) | 193 (87) | 192 (87) | −0.04 | 0.25 |
| Inflammation | |||||
| Hs-CRP, mg/L | 1.3 (0.5–3.5) | 1.6 (0.7–4.4) | 1.9 (0.9–5.6) | 0.10 | 0.007 |
| Renal function | |||||
| eGFR, ml/min/1.73 m2 | 44.7 ± 20.0 | 46.0 ± 18.5 | 46.6 ± 17.7 | 0.09 | 0.03 |
| Proteinuria, n (%) | 47 (22) | 47 (21) | 38 (17) | −0.06 | 0.14 |
| Immunosuppressive medication | |||||
| Prednisolon dose, mg/day | 7.5 (7.5–10) | 7.5 (7.5–10) | 7.5 (7.5–10) | 0.02 | 0.54 |
| Calcineurin inhibitor, n (%) | 131 (60) | 127 (58) | 115 (48) | −0.05 | 0.23 |
| Tacrolimus, n (%) | 38 (17) | 49 (22) | 33 (15) | −0.02 | 0.54 |
| Cyclosporine, n (%) | 93 (43) | 78 (35) | 82 (37) | −0.03 | 0.46 |
| Proliferation inhibitor, n (%) | 172 (79) | 183 (83) | 193 (88) | 0.10 | 0.01 |
| Azathioprine, n (%) | 35 (16) | 32 (15) | 45 (21) | 0.04 | 0.36 |
| Mycophenolic acid, n (%) | 137 (63) | 151 (68) | 148 (67) | 0.05 | 0.21 |
| Nonimmunosuppressive medication | |||||
| Acetylsalicylic acid, n (%) | 55 (25) | 34 (15) | 38 (17) | −0.08 | 0.03 |
| Anticonvulsant, n (%) | 9 (4) | 4 (2) | 6 (3) | −0.02 | 0.59 |
| Proton pump inhibitor, n (%) | 122 (56) | 99 (45) | 105 (48) | −0.09 | 0.03 |
| Diuretic, n (%) | 95 (43) | 76 (34) | 90 (41) | −0.05 | 0.21 |
| Renal transplantation | |||||
| Time since transplantation, years | 5.9 (2.6–13.4) | 5.1 (1.4–10.7) | 5.8 (2.4–12.2) | −0.02 | 0.65 |
| Donor | |||||
| Age, years | 44 (28–53) | 47 (33–56) | 44 (31–54) | 0.002 | 0.97 |
| Male, n (%) | 108 (50) | 114 (52) | 104 (50) | −0.04 | 0.31 |
| Post mortem status, n (%) | 150 (69) | 133 (61) | 142 (66) | 0.04 | 0.36 |
| Primary renal disease | |||||
| Primary glomerular disease, n (%) | 57 (26) | 68 (31) | 61 (28) | 0.01 | 0.81 |
| Glomerulonephritis, n (%) | 15 (7) | 17 (8) | 18 (8) | 0.06 | 0.14 |
| Tubulointerstitial disease, n (%) | 26 (12) | 28 (13) | 23 (11) | −0.02 | 0.54 |
| Polycystic renal disease, n (%) | 41 (19) | 42 (19) | 54 (25) | 0.02 | 0.59 |
| Dysplasia and hypoplasia, n (%) | 10 (5) | 10 (5) | 8 (4) | −0.01 | 0.79 |
| Renovascular disease, n (%) | 15 (7) | 8 (4) | 13 (6) | −0.04 | 0.29 |
| Diabetic nephropathy, n (%) | 14 (6) | 13 (6) | 8 (4) | −0.03 | 0.46 |
| Other or unknown cause, n (%) | 40 (18) | 35 (16) | 35 (16) | −0.005 | 0.90 |
1 Normally distributed, skewed, and nominal data are presented as mean ± SD, median (IQR), and absolute number (percentage), respectively. 2 Cross-sectional associations of N1-MN + 2Py excretion with baseline variables were investigated with linear regression analyses, with adjustment for sex, of which std. β and p-value are presented. BMI, body mass index; eGFR, estimated glomerular filtration rate; HbA1c, hemoglobin A1c; HDL, high-density lipoprotein; hs-CRP, high-sensitivity C-reactive protein; LDL, low-density lipoprotein; N1-MN, N1-methylnicotinamide; KTR, kidney transplant recipients; std. β, standardized β; 2Py, N1-methyl-2-pyridone-5-carboxamide; 2Py/N1-MN, ratio of 2Py to N1-MN.