Table 2.
Baseline characteristics of adults with primary NS and matched adults without NS identified between 1996–2012
| Characteristic | Adults with Primary NS | Adults without NS | Standardized Difference |
|---|---|---|---|
| (n=907) | (n=89,593) | ||
| Demographic characteristics | |||
| Mean (SD) age, yr | 49.0 (16.8) | 49.2 (16.7) | 0.01 |
| Women, n (%) | 390 (43.0) | 50,857 (56.8) | 0.28 |
| Self-reported race, n (%) | 0.12 | ||
| White/European | 375 (41.3) | 49,119 (54.8) | |
| Black | 131 (14.4) | 6277 (7.0) | |
| Asian/Pacific Islander | 166 (18.3) | 12,025 (13.4) | |
| Other | 75 (8.3) | 4970 (5.5) | |
| Unknown | 160 (17.6) | 17,202 (19.2) | |
| Hispanic ethnicity, n (%) | 176 (19.4) | 12,571 (14.0) | 0.15 |
| Low household educational attainment, n (%) | 226 (24.9) | 17,537 (19.6) | 0.13 |
| Median household income <$35,000, n (%) | 104 (11.5) | 8956 (10.0) | 0.05 |
| Current or former smoker, n (%) | 198 (21.8) | 19,063 (21.3) | 0.01 |
| Medical history, n (%) | 4 (1.1) | ||
| Myocardial infarction | 10 (1.1) | 518 (0.6) | 0.39 |
| Unstable angina | 6 (0.7) | 347 (0.4) | 0.33 |
| Heart failure | 25 (2.8) | 915 (1.0) | 0.61 |
| Ischemic stroke | 5 (0.6) | 236 (0.3) | 0.45 |
| Transient ischemic attack | 8 (0.9) | 384 (0.4) | 0.44 |
| Venous thromboembolism | 3 (0.3) | 148 (0.2) | 0.22 |
| Peripheral artery disease | 8 (0.9) | 434 (0.5) | 0.37 |
| Hypertension | 368 (40.6) | 20,571 (23.0) | 0.50 |
| Dyslipidemia | 370 (40.8) | 20,589 (23.0) | 0.51 |
| Chronic liver disease | 13 (1.4) | 1470 (1.6) | 0.08 |
| Chronic lung disease | 139 (15.3) | 12,214 (13.6) | 0.08 |
| Asthma | 119 (13.1) | 10,257 (11.4) | 0.09 |
| Hyperthyroidism | 25 (2.8) | 1929 (2.2) | 0.15 |
| Hypothyroidism | 116 (12.8) | 7619 (8.5) | 0.28 |
| Diagnosed dementia | 3 (0.3) | 617 (0.7) | 0.45 |
| Cancer | 40 (4.4) | 5278 (5.9) | 0.18 |
| Cardiac procedure history, n (%) | |||
| Coronary artery bypass graft surgery | 5 (0.6) | 355 (0.4) | 0.20 |
| Percutaneous coronary intervention | 14 (1.5) | 645 (0.7) | 0.47 |
| Medication use, n (%) | |||
| ACE inhibitor | 229 (25.2) | 9329 (10.4) | 0.65 |
| Angiotensin II receptor blocker | 67 (7.4) | 1760 (2.0) | 0.84 |
| Beta-blocker | 180 (19.8) | 10,522 (11.7) | 0.38 |
| Calcium channel blocker | 130 (14.3) | 4520 (5.0) | 0.70 |
| Diuretic | 371 (40.9) | 13,585 (15.2) | 0.82 |
| Alpha antagonist | 72 (7.9) | 2687 (3.0) | 0.62 |
| Aldosterone receptor antagonist | 13 (1.4) | 419 (0.5) | 0.68 |
| Other antihypertensive agent | 522 (57.6) | 25,590 (28.6) | 0.74 |
| Antiarrhythmic agent | 1 (0.1) | 391 (0.4) | 0.84 |
| Digoxin | 9 (1.0) | 984 (1.1) | 0.06 |
| Statin | 224 (24.7) | 11,016 (12.3) | 0.52 |
| Other lipid-lowering agent | 35 (3.9) | 1166 (1.3) | 0.67 |
| Warfarin | 28 (3.1) | 1616 (1.8) | 0.33 |
| Platelet aggregation inhibitor | 10 (1.1) | 662 (0.7) | 0.24 |
| Nonsteroidal anti-inflammatory drug | 117 (12.9) | 13,777 (15.4) | 0.12 |
| Vital signs | |||
| Body mass index, kg/m2, n (%) | 0.12 | ||
| <18.5 | 7 (0.8) | 655 (0.7) | |
| 18.5–25.0 | 110 (12.1) | 16,502 (18.4) | |
| 25.0–29.9 | 157 (17.3) | 17,116 (19.1) | |
| 30.0–39.9 | 195 (21.5) | 14,975 (16.7) | |
| ≥40.0 | 27 (3.0) | 1553 (1.7) | |
| Unknown | 411 (45.3) | 38,792 (43.3) | |
| Systolic blood pressure, mmHg, n (%) | 0.33 | ||
| <120 | 135 (14.9) | 29,377 (32.8) | |
| 121–130 | 110 (12.1) | 13,774 (15.4) | |
| 131–139 | 174 (19.2) | 14,804 (16.5) | |
| 140–159 | 153 (16.9) | 7235 (8.1) | |
| 160–179 | 48 (5.3) | 1428 (1.6) | |
| ≥180 | 20 (2.2) | 298 (0.3) | |
| Unknown | 267 (29.4) | 22,677 (25.3) | |
| Diastolic blood pressure, mmHg, n (%) | 0.24 | ||
| ≤80 | 372 (41.0) | 50,478 (56.3) | |
| 81–84 | 71 (7.8) | 6944 (7.8) | |
| 85–89 | 83 (9.2) | 5283 (5.9) | |
| 90–99 | 69 (7.6) | 3371 (3.8) | |
| 100–109 | 29 (3.2) | 697 (0.8) | |
| ≥ 110 | 15 (1.7) | 108 (0.1) | |
| Unknown | 268 (29.5) | 22,712 (25.4) | |
| Laboratory values | |||
| Estimated glomerular filtration rate, ml/min per 1.73m2 | 2.01 | ||
| ≥90 | 268 (29.5) | 46,809 (52.2) | |
| 60–89 | 176 (19.4) | 35,990 (40.2) | |
| 45–59 | 106 (11.7) | 4864 (5.4) | |
| 30–44 | 112 (12.3) | 1404 (1.6) | |
| 15–29 | 106 (11.7) | 256 (0.3) | |
| <15 | 37 (4.1) | 27 (0.0) | |
| Unknown | 102 (11.2) | 243 (0.3) | |
| Serum albumin, mg/dl | |||
| Mean (SD) | 2.8 (0.9) | 4.3 (0.4) | 2.95 |
| Missing, n (%) | 382 (42.1) | 81,310 (90.8) | |
| Total cholesterol, mg/dl | 0.47 | ||
| <200 | 149 (16.4) | 32,194 (35.9) | |
| 200–240 | 99 (10.9) | 20,558 (22.9) | |
| >240 | 361 (39.8) | 9,304 (10.4) | |
| Unknown | 298 (32.9) | 27,537 (30.7) | |
| Hemoglobin, g/dl | 0.24 | ||
| >13.0 | 460 (50.7) | 56,989 (63.6) | |
| 12.0–12.9 | 107 (11.8) | 11,756 (13.1) | |
| 11.0–11.9 | 78 (8.6) | 4061 (4.5) | |
| 10.0–10.9 | 44 (4.9) | 1289 (1.4) | |
| 9.0–9.9 | 22 (2.4) | 466 (0.5) | |
| <9.0 | 11 (1.2) | 261 (0.3) | |
| Unknown | 185 (20.4) | 14,771 (16.5) |