Table 1.
Excretion of 2Py and N1-MN and kidney function in RTR and kidney donors before and after kidney donation 1.
| RTR | Kidney Donors | Population | Kidney Donors | Paired | ||
|---|---|---|---|---|---|---|
| Variable | n = 660 | n = 275 | Difference | n = 85 | Difference | |
| Total Cohort | Total Cohort | p-Value 2 | Pre-Donation | Post-Donation | p-Value 3 | |
| Age, years | 53.0 ± 12.7 | 53.3 ± 10.7 | 0.68 | 52.2 ± 10.5 | 52.6 ± 10.4 | <0.001 |
| Male, n (%) | 379 (57) | 112 (41) | 0.001 | 43 (51) | 43 (51) | - |
| Body surface area, m2 | 1.9 ± 0.2 | 1.9 ± 0.2 | 0.90 | 2.0 ± 0.2 | 1.9 ± 0.2 | 0.01 |
| BMI, kg/m2 | 26.6 ± 4.8 | 25.9 ± 3.4 | 0.01 | 26.0 ± 3.4 | 25.7 ± 3.2 | 0.03 |
| Urinary excretion | ||||||
| 2Py, μmol/day | 178.1 (130.3–242.8) | 155.6 (119.6–217.6) | 0.001 | 152.8 (124.4–215.1) | 161.7 (116.6–227.8) | 0.31 |
| N1-MN, μmol/day | 22.0 (15.8–31.8) | 41.4 (31.6–57.2) | <0.001 | 40.9 (31.0–58.2) | 32.5 (23.4–44.0) | <0.001 |
| 2Py/N1-MN | 8.7 ± 3.8 | 4.0 ± 1.4 | <0.001 | 4.0 ± 1.4 | 5.2 ± 1.5 | <0.001 |
| Sum of 2Py and N1-MN, μmol/day | 198.3 (155.9–269.4) | 203.7 (149.4–274.7) | 0.98 | 198.3 (162.3–270.8) | 189.7 (141.9–271.6) | 0.90 |
| 2Py fraction, % 4 | 89.1 (86.4–91.3) | 79.0 (75.6–82.1) | <0.001 | 78.3 (75.5–81.8) | 83.5 (80.0–86.0) | <0.001 |
| N1-MN fraction, % 4 | 10.9 (8.7–13.6) | 21.0 (17.9–24.4) | <0.001 | 21.7 (18.2–24.5) | 16.5 (14.0–20.0) | <0.001 |
| Kidney function | ||||||
| eGFR, mL/min/1.73 m2 | 45.8 ± 18.7 | 91.0 ± 14.2 | <0.001 | 92.8 ± 13.9 | 60.1 ± 12.1 | <0.001 |
| GFR, mL/min/1.73 m2 | 52.4 ± 17.4 | 82.3 ± 29.7 | <0.001 | 103.7 ± 16.7 | 65.3 ± 10.4 | <0.001 |
1 Data are presented as mean ± SD, median (IQR) and absolute number (percentage) for normally distributed, skewed and nominal data, respectively. 2 p-value for difference between RTR and the total cohort of kidney donors was tested by t and Mann–Whitney tests for normally and skewed distributed continuous variables, respectively. 3 p-value for difference between kidney donors before and after kidney donation was tested by paired samples t and Wilcoxon signed rank tests for normally and skewed distributed continuous variables, respectively. 4 The urinary fraction of 2Py or N1-MN (percentage) was calculated by dividing 2Py or N1-MN excretion by the sum of 2Py and N1-MN excretion, respectively, and multiplying by 100. BMI, body mass index; eGFR, estimated glomerular filtration rate; GFR, glomerular filtration rate; N1-MN, N1-methylnicotinamide; RTR, renal transplant recipients; 2Py, N1-methyl-2-pyridone-5-carboxamide; 2Py/N1-MN, ratio of 2Py to N1-MN.