Table 4. Clinical and laboratory characteristics according to caffeine intake.
| Parameters | Caffeine intake | ||
|---|---|---|---|
| 0-41.6 mg/day (N = 34) | 41.7-98.7 mg/day (N = 34) | 98.8-471.4 mg/day (N = 34) | |
| Age (years) | 36 ± 12 | 39 ± 13 | 43 ± 11 |
| Time since diagnosis (months) | 112 ± 103 | 99 ± 88 | 101 ± 99 |
| CKD1/2 (N, %) | 21 (62) | 19 (56) | 23 (68) |
| CKD3 (N, %) | 13 (38) | 15 (44) | 11 (32) |
| Hypertension (N, %) | 16 (47) | 26 (76) | 22 (65) |
| Serum creatinine (mg/dL) | 1.3 ± 0.73 | 1.3 ± 0.7 | 1.4 ± 1.2 |
| eGFR [mL·min−1·(1.73 m2)−1] | 74 ± 33 | 74 ± 35 | 73 ± 35 |
| Renal volume (mL) | 787 (306-3848) | 1100 (260-5517) | 746 (219-3588) |
Parametric variables are reported as means ± SD. Renal volume (nonparametric variable) is reported as median (25th to 75th percentile). CKD1/2 = chronic kidney disease stages 1/2; CKD3 = chronic kidney disease stage 3; eGFR = estimated glomerular filtration rate. No statistically significant differences were detected among tertiles (ANOVA or chi-square test for categorical variables).