Table 1.
Descriptive statistics overall and by hilar renal artery resistive index (RI) dichotomized at 0.8.
| Overall | RI ≥ 0.8 | RI < 0.8 | ||
|---|---|---|---|---|
| Variable | N = 726† | N = 184‡ | N = 542€ | P-value |
| Age in years* (mean ± SD) | 77.0 ± 4.8 | 78.6 ± 5.5 | 76.5 ± 4.4 | <0.001 |
| African-American race** (frequency [%]) | 161 (22.2) | 40 (21.7) | 121 (22.3) | 0.9 |
| Men** (frequency [%]) | 264 (36.4) | 60 (32.6) | 204 (37.6) | 0.2 |
| Systolic blood pressure*, mmHg (mean ± SD) | 136.1 ± 20.3 | 139.8 ± 22.6 | 134.9 ± 19.3 | 0.01 |
| Diastolic blood pressure*, mmHg (mean ± SD) | 72.0 ± 10.3 | 69.0 ± 10.2 | 73.1 ±10.1 | <0.001 |
| Height*, cm (mean ± SD) | 170 ± 24 | 171.1 ± 33.1 | 169.2 ± 19.9 | 0.5 |
| Weight*, kg (mean ± SD) | 71.9 ± 13.3 | 72.3 ± 14.2 | 71.8 ± 12.9 | 0.6 |
| Current or former of cigarette smoker* (frequency [%]) | 348 (47.9) | 91 (49.5) | 257 (47.4) | 0.6 |
| Estimated GFR*, mL/min/1.73m2 from 4-variable MDRD# equation (mean ± SD) | 69.9 ± 15.5 | 68.6 ± 17.0 | 70.3 ± 15.0 | 0.2 |
| Serum creatinine*, mg/dL (mean ± SD) | 1.00 ± 0.27 | 1.03 ± 0.29 | 0.99 ± 0.26 | 0.09 |
| Renal insufficiency*, estimated GFR <60 mL/min/1.73m2 (frequency [%]) | 59 (8.2) | 23 (12.6) | 36 (6.7) | 0.01 |
| History of Coronary Artery Disease (CAD): myocardial infarct, hospitalized angina, or coronary revascularization* (frequency [%]) | 157 (21.6) | 53 (28.8) | 104 (19.2) | 0.01 |
| History of stroke or transient ischemic attack* (frequency [%]) | 51 (7.0) | 22 (12.0) | 29 (5.4) | 0.002 |
| Prevalent CAD or CVD, history of CHF, atrial fibrillation, AAA, claudication or peripheral vascular disease, or a history of internal carotid artery stenosis (>75%) or carotid endarterectomy* (frequency [%]) | 261 (36.0) | 84 (45.7) | 177 (32.7) | 0.002 |
| Hypertension: SBP > 160 mmHg, DBP > 95 mmHg, or use of antihypertensive agent* (frequency [%]) | 368 (50.7) | 114 (62.0) | 254 (46.9) | <0.001 |
| Use of any antihypertensive medication at time of RDS* (frequency [%]) | 401 (55.2) | 122 (66.3) | 279 (51.5) | <0.001 |
| Hypercholesterolemia by National Cholesterol Education Program guidelines* (frequency [%]) | 257 (35.4) | 64 (34.8) | 193 (35.6) | .8 |
| Diabetes by fasting serum glucose > 140 mg/dL, 2-hour post glucose load serum glucose >200 mg/dL, or insulin/oral hypoglycemic agent use* (frequency [%]) | 168 (23.1) | 57 (31.0) | 111 (20.5) | 0.004 |
| Peripheral vascular disease (PVD) by ankle-brachial index ≤ 0.90 (frequency [%]) | 64 (8.9) | 22 (12.1) | 42 (7.8) | 0.08 |
| ECG: any major ECG abnormality (frequency [%]) | 216 (29.8) | 61 (33.2) | 155 (28.6) | 0.2 |
| Echo: LV ejection fraction <50% or major wall motion abnormality (frequency [%]) | 27 (3.8) | 8 (4.4) | 19 (3.5) | 0.6 |
| BSA-adjusted kidney length, cm/m2 (mean ± SD) | 5.77 ± 0.63 | 5.78 ± 0.66 | 5.77 ± 0.62 | 0.9 |
| RA peak systolic velocity (PSV), max of left or right side, m/sec (mean ± SD) | 1.26 ± 0.50 | 1.30 ± 0.47 | 1.24 ± 0.51 | 0.2 |
| RA end diastolic velocity, max of left or right side, m/sec (mean ± SD) | 0.31 ± 0.15 | 0.26 ± 0.10 | 0.33 ± 0.16 | <0.001 |
| Parenchymal peak systolic frequency shift (PSF). max of left or right side, kHz (mean ± SD) | 1550 ± 543 | 1595 ± 541 | 1535 ± 543 | 0.2 |
| Parenchymal end diastolic frequency shift (EDF), max of left or right side, kHz (mean ± SD) | 380 ± 132 | 348 ± 120 | 391 ± 134 | <0.001 |
| Hilar renal artery resistive index (RI), from side with max PSV, % (mean ± SD) | 0.76 ± 0.06 | |||
| RI ≥ 0.8, from side with max PSV (frequency [%]) | 184 (25.3) |
*
Parameter recorded/updated at nearest visit prior to or concurrent with the renal duplex examination
**
Parameter recorded at initial baseline examination
†
N=723 for estimated GFR, serum creatinine, and renal insufficiency; N=724 for kidney length; N=718 for PVD
‡
N=183 for estimated GFR, serum creatinine, and renal insufficiency; N=182 for PVD and echo parameters
€
N=540 for estimated GFR, serum creatinine, renal insufficiency, and kidney length; N=536 for PVD; N=538 for echo parameters