Table 1.
Demographics and estimates of kidney function in the CRISP population at baseline
| Characteristic | Total N = 239 | Caffeine Consumer N = 188 (79) | Non-Caffeine Consumer N = 51 (21) | P-value for difference between caffeine and non-caffeine consumers | |
|---|---|---|---|---|---|
| Age*, years | Mean (± sd) | 32.3 ± 8.7 | 32.3 ± 8.9 | 32.4 ± 9.0 | 0.935 |
| Median (IQR) | 33.8 (25.1, 39.7) | 33.6 (25.0, 39.7) | 34.2 (16.0, 39.4) | ||
| Race (White), n (%) | 207 (87) | 167 (89) | 40 (78) | 0.089 | |
| Sex (Male), n (%) | 96 (40) | 78 (41) | 18 (35) | 0.523 | |
| BMI*, kg/m2 | Mean (± sd) | 25.91 ± 5.3 | 26.1 ± 5.5 | 25.3 ± 4.3 | 0.564 |
| Median (IQR) | 25.17 (21.98, 28.64) | 25.24 (22.04, 29.03) | 25.07 (22.06, 27.64) | ||
| Smoking, n (%) | 40 (17) | 36 (19) | 4 (8) | 0.088 | |
| Hypertension, n (%) | 146 (61) | 113 (60) | 33 (65) | 0.663 | |
| Genotype, n (%) | |||||
| PKD1 + truncation | 127 (53) | 100 (53) | 27 (53) | ||
| PKD1 + no truncation | 60 (25) | 49 (26) | 11 (22) | 0.691 | |
| PKD2 + NMD | 52 (22) | 39 (21) | 13 (25) | ||
| htTKV*, ml/m | Mean (± sd) | 621.6 ± 373.9 | 606.6 ± 367.7 | 683.7 ± 403.5 | 0.222 |
| Median (IQR) | 504.4 (350.2, 773.9) | 479.9 (342.4, 726.9) | 567.5 (382.6, 872.7) | ||
| Iothalamate Clearance*ϕ, ml/min/1.73m2 | Mean (± sd) | 97.7 ± 24.8 | 98.2 ± 24.6 | 96.9 ± 25.2 | 0.358 |
| Median (IQR) | 94.70 (78.78, 114.75) | 96.36 (78.74, 114.72) | 88.71 (79.05, 114.83) | ||
Values are given for the total population and based on caffeine intake. *P-value based on Wilcoxon rank sum test due to violation of t-test assumptions. ϕN = 234 (5 values missing at baseline but contributed subsequent measures for mixed model results). NMD refers to no mutation detected in the genetic analysis