Table 1. Clinical characteristics at baseline of the 243 participants in RASS with type 1 diabetes who had two kidney biopsies and measurements of plasma bradykinin and related peptides, and the subsets with cortical interstitial fractional volume and glomerular volume measurements.
| Variable | Entire cohort (N = 243) | Vv(Int/cortex) subsets | P | GlomV subsets | P | ||
|---|---|---|---|---|---|---|---|
| Cohort with Vv(Int/cortex) measurements (N = 189) | Cohort without Vv(Int/cortex) measurements (N = 54) | Cohort with GlomV measurements (N = 156) | Cohort without GlomV measurements (N = 87) | ||||
| RASS treatment assignment (%) | |||||||
| Placebo | 81 (33) | 66 (35) | 15 (28) | 0.322 | 52 (33) | 29 (33) | 0.973 |
| Enalapril | 79 (33) | 63 (33) | 16 (30) | 50 (32) | 29 (33) | ||
| Losartan | 83 (34) | 60 (32) | 23 (43) | 54 (35) | 29 (33) | ||
| Age (years) | 29.8±9.6 | 30.3±9.5 | 28.1±9.9 | 0.140 | 29.5±9.8 | 30.5±9.3 | 0.426 |
| Number men (%) | 113 (47) | 90 (48) | 23 (43) | 0.514 | 70 (45) | 43 (49) | 0.495 |
| Number white (%) | 237 (98) | 184 (97) | 53 (98) | 0.740 | 153 (98) | 84 (97) | 0.463 |
| Diabetes duration (years) | 11.3±4.9 | 11.5±4.8 | 10.6±5.1 | 0.250 | 11.1±4.7 | 11.6±5.1 | 0.446 |
| HbA1c (%) | 8.5±1.6 | 8.5±1.5 | 8.7±1.8 | 0.268 | 8.6±1.5 | 8.5±1.6 | 0.663 |
| (mmol/mol) | 69.9±17.0 | 69.2±16.2 | 72.1±19.4 | 70.2±16.6 | 69.2±17.7 | ||
| Systolic BP (mm Hg) | 120±12 | 120±12 | 119±12 | 0.682 | 120±12 | 119±11 | 0.813 |
| Diastolic BP (mm Hg) | 70±8 | 71±8 | 68±7 | 0.084 | 70±9 | 70±7 | 0.910 |
| AER (μg/min) | 5.0 (3.3–7.8) | 5.1 (3.6–7.8) | 4.8 (3.1–7.8) | 0.524 | 4.7 (3.2–6.9) | 5.9 (3.8–9.1) | 0.014 |
| iGFR (ml/min/1.73m2) | 128±19 | 128±19 | 129±18 | 0.545 | 126±19 | 131±17 | 0.047 |
| BK (nM) | 15.0 (7.4–37.8) | 15.3 (8.2–44.2) | 12.3 (6.1–26.3) | 0.117 | 13.9 (8.2–34.7) | 22.2 (6.2–54.8) | 0.602 |
| BK(1–7) (nM) | 38.0 (18.5–66.6) | 38.4 (18.3–69.7) | 35.1 (21.9–50.4) | 0.350 | 36.1 (18.4–68.5) | 41.3 (21.7–64.7) | 0.726 |
| BK(1–8) (nM) | 11.7 (4.8–33.2) | 11.8 (4.8–31.8) | 9.6 (5.2–33.2) | 0.419 | 11.2 (4.9–30.6) | 13.7 (4.5–38.5) | 0.905 |
| Hyp3-BK (nM) | 18.7 (10.3–48.7) | 20.4 (10.8–50.0) | 15.6 (7.3–35.0) | 0.138 | 17.5 (10.7–46.1) | 20.9 (8.4–52.5) | 0.982 |
| Hyp3-BK(1–7) (nM) | 52.0 (27.7–89.7) | 52.4 (29.0–88.9) | 49.9 (26.4–94.8) | 0.714 | 52.2 (29.2–87.5) | 50.2 (25.7–92.0) | 0.594 |
| Hyp3-BK(1–8) (nM) | 18.2 (8.9–39.7) | 18.2 (9.6–41.7) | 17.7 (6.5–35.3) | 0.527 | 18.0 (9.6–38.9) | 19.4 (7.7–41.7) | 0.808 |
| Unmodified peptides (nM) | 64.6 (39.1–141.5) | 64.5 (39.1–150.0) | 66.5 (40.1–100.1) | 0.516 | 63.7 (37.8–138.7) | 75.9 (41.9–143.7) | 0.373 |
| Hydroxylated peptides (nM) | 102.3 (59.8–190.9) | 98.8 (59.8–199.5) | 105.5 (61.6–142.0) | 0.595 | 96.4 (60.6–177.8) | 108.9 (59.8–224.9) | 0.884 |
| All peptides (nM) | 167.0 (104.7–333.5) | 167.0 (104.4–387.4) | 167.1 (128.6–277.3) | 0.747 | 162.6 (103.9–331.1) | 172.2 (120.3–369.5) | 0.550 |
Data are numbers (percents), means±SD, or medians (IQR). P-values are for differences in clinical characteristics between participants with specific measurement and those without. Abbreviations used: AER, albumin excretion rate; BP, blood pressure; HbA1c, glycosylated hemoglobin; iGFR, iohexol glomerular filtration rate; RASS, Renin-Angiotensin System Study; Vv(Int/cortex), interstitial cortical fractional volume; GlomV, mean glomerular volume BK, bradykinin; BK(1–7), bradykinin (1–7); BK(1–8), bradykinin (1–8); hyp3-BK, hydroxylated bradykinin; hyp3-BK(1–7) hydroxylated bradykinin (1–7); hyp3-BK(1–8) hydroxylated bradykinin (1–8).