Table.
Characteristics of Non–Loop Users and Loop Users
| Characteristic | Median (Quartiles 1–3) | P Valuea | |
|---|---|---|---|
| Non–Loop Users (n = 8801) | Loop Users (n = 162) | ||
| Age, y | 41.7 (29.9–53.1) | 65.7 (55.7–74.9) | <.001 |
| Male, % | 48.7 | 36.4 | <.001 |
| African American, % | 22.8 | 25.3 | .15 |
| BMI | 27.1 (23.7–31.5) | 31.4 (27.2–38.7) | <.001 |
| Current smoker, %b | 21.3 | 13.6 | .01 |
| Hyperparathyroidism, %c | 6.5 | 19.8 | <.001 |
| History of CHF, % | 1.4 | 32.1 | <.001 |
| eGFR, mL/mind | 96.5 (82.8–109.9) | 76.3 (67.6–88.7) | <.001 |
| Calcium level, mg/dL | 9.5 (9.3–9.7) | 9.4 (9.2–9.6) | .08 |
| Phosphorus level, mg/dL | 3.7 (3.4–4.1) | 3.7 (3.4–4.1) | .35 |
| Uric acid level, mg/dL | 5.2 (4.2–6.1) | 5.6 (4.9–6.7) | <.001 |
| Albumin level, g/dL | 0.42 (0.40–0.45) | 0.40 (0.38–0.42) | <.001 |
| Alkaline phosphatase level, U/L | 64.2 (53.1–78.3) | 77.1 (65.4–99.3) | <.001 |
| PTH level, pg/mL | 37.4 (28.2–49.0) | 51.5 (41.3–69.4) | <.001 |
| Total 25 (OH) vitamin D level, ng/mL | 22.7 (16.8–28.7) | 18.3 (13.1–23.6) | <.001 |
| Dietary calcium level, mg/d | 413.1 (268.8–631.3) | 330.7 (237.4–511.2) | <.001 |
| Dietary phosphorus level, mg/d | 667.4 (473.1–912.8) | 515.4 (375.6–705.8) | <.001 |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CHF, congestive heart failure; CKD, chronic kidney disease; cr, creatinine; eGFR, estimated glomerular filtration rate; EPI, Epidemiology Collaboration; GFR, glomerular filtration rate; PTH, parathyroid hormone.
SI conversion factors: To convert albumin to grams per liter, multiply by 10; to convert alkaline phosphatase to microkatals per liter, multiply by 0.0167; to convert calcium to millimoles per liter, multiply by 0.25; to convert 25-hydroxyvitamin D to nanomoles per liter, multiply by 2.496; to convert uric acid to micromoles per liter, multiply by 59.485.
Bold font indicates statistical significance (P < .05).
Defined as having smoked more than 100 cigarettes in one’s lifetime and still smoking some or most days of the week.
Defined as PTH level greater than 65 pg/mL.
Calculated using CKD-EPI (GFR = 141 × min (Scr/κ, 1)α × max (Scr/κ, 1)−1.209 × 0.993Age × 1.018 [if female] × 1.159 [if black], where Scr indicates serum creatinine and κ is a correction factor, defined as follows: →0.7 if female and →0.9 if male.