Table 1. Characteristics of Study Participants and by Lp(a) Level Categoriesa.
| No. (%) | P value | ||||
|---|---|---|---|---|---|
| Overall (n = 16 513) | Normal level (n = 11 621) | High level (n = 4071) | Very high level (n = 821) | ||
| Age, median (IQR), y | 58.2 (49.0-66.7) | 58.0 (48.6-66.7) | 58.3 (49.6-66.7) | 60.1 (51.9-67.8) | <.001 |
| Female sex | 6739 (40.8) | 4528 (39.0) | 1790 (44.0) | 421 (51.3) | <.001 |
| Male sex | 9774 (59.2) | 7093 (61.0) | 2281 (56.0) | 400 (48.7) | <.001 |
| PAD | 1139 (6.9) | 726 (6.2) | 313 (7.7) | 100 (12.2) | <.001 |
| History of ischemic heart disease | 2387 (14.5) | 1548 (13.3) | 681 (16.7) | 158 (19.2) | <.001 |
| History of stroke | 204 (1.2) | 122 (1.0) | 65 (1.6) | 17 (2.1) | .002 |
| Arterial hypertension | 9062 (54.9) | 6310 (54.3) | 2255 (55.4) | 497 (60.5) | .002 |
| Cigarette use | |||||
| Never | 11 349 (68.7) | 7824 (67.3) | 2899 (71.2) | 626 (76.2) | <.001 |
| Former | 2770 (16.8) | 2017 (17.4) | 647 (15.9) | 106 (12.9) | |
| Current | 2394 (14.5) | 1780 (15.3) | 525 (12.9) | 89 (10.8) | |
| Dyslipidemia | 10 502 (63.6) | 7126 (61.3) | 2810 (69.0) | 566 (68.9) | <.001 |
| Diabetes | 2146 (13.0) | 1480 (12.7) | 521 (12.8) | 145 (17.7) | <.001 |
| Dialysis | 75 (0.5) | 52 (0.4) | 17 (0.4) | 6 (0.7) | .47 |
| Lp(a) | |||||
| Median (IQR), mg/dL | 24 (10-60) | 15 (7-27) | 78 (62-10) | 168 (150-202) | |
| By level category | 16 513 (100.0) | 11 621 (70.4) | 4071 (24.7) | 821 (5.0) | |
| Cholesterol level, median (IQR), mg/dL | |||||
| LDL | 118.33 (92.42-146.56) | 117.56 (91.65-144.62) | 120.26 (94.35-150.43) | 120.65 (93.19-156.23) | <.001 |
| HDL | 48.72 (39.83-59.94) | 48.34 (39.06-59.55) | 49.50 (40.99-60.71) | 52.20 (42.54-64.19) | <.001 |
| Total | 194.51 (165.12-227.38) | 193.35 (163.96-225.06) | 197.60 (167.44-231.63) | 201.08 (170.92-242.07) | <.001 |
| Triglyceride level, median (IQR), mg/dL | 106.19 (76.11-153.10) | 107.08 (76.11-155.75) | 104.42 (75.22-146.90) | 107.08 (78.76-156.64) | .002 |
| Serum creatinine level, median (IQR), mg/dL | 0.90 (0.76-1.10) | 0.90 (0.76-1.09) | 0.92 (0.76-1.12) | 0.96 (0.77-1.26) | <.001 |
| Measured GFR, median (IQR), mL/min/1.73 m2 | 80 (66-93) | 80 (67-93) | 78 (64-92) | 72 (53-89) | <.001 |
| Proteinuria, median (IQR), g/L | 0.12 (0.08-0.18) | 0.12 (0.08-0.18) | 0.12 (0.08-0.18) | 0.12 (0.07-0.23) | .24 |
| Conjugated bilirubin level, median (IQR), mg/dL | 0.23 (0.18-0.29) | 0.23 (0.18-0.29) | 0.23 (0.18-0.29) | 0.18 (0.12-0.23) | .71 |
| Total bilirubin level, median (IQR), mg/dL | 0.70 (0.53-0.88) | 0.70 (0.53-0.94) | 0.70 (0.53-0.88) | 0.64 (0.18-0.29) | <.001 |
| γ-glutamyltransferase level, median (IQR), U/L | 22 (14-37) | 22 (13-38) | 22 (14-37) | 23 (14-40) | .51 |
| Alkaline phosphatase level, median (IQR), U/L | 60 (50-74) | 60 (49-73) | 62 (51-76) | 67 (54-83) | <.001 |
| Alanine aminotransferase level, median (IQR), U/L | 21 (15-30) | 21 (15-31) | 21 (15-29) | 18 (13-26) | <.001 |
| Aspartate aminotransferase level, median (IQR), U/L | 21 (17-26) | 21 (17-26) | 21 (17-26) | 21 (17-26) | .64 |
| Serum albumin, median (IQR), g/dL | 3.8 (3.4-4.1) | 3.8 (3.5-4.1) | 3.7 (3.2-4.0) | 3.7 (3.0-3.9) | <.001 |
| Lipid-lowering drugs, No./total No. (%) | 1520/2852 (53.3) | 944/1901 (49.7) | 435/749 (58.1) | 141/202 (69.8) | <.001 |
| Follow-up duration, median (IQR), y | 3.74 (1.07-7.30) | 3.80 (1.11-7.35) | 3.64 (1.01-7.27) | 3.29 (1.08-6.74) | .02 |
Abbreviations: GFR, glomerular filtration rate; HDL, high-density lipoprotein; LDL, low-density lipoprotein; Lp(a), lipoprotein(a); PAD, peripheral artery disease.
SI conversion factors: To convert alkaline phosphatase to microkatal per liter, multiply by 0.0167; ALT and AST to microkatal per liter, multiply by 0.0167; bilirubin to micromoles per liter, multiply by 17.104; γ-glutamyltransferase to microkatal per liter, multiply by 0.0167; LDL, HDL, and total cholesterol to millimoles per liter, multiply by 0.0259; Lp(a) to milligrams per liter, multiply by 0.1; serum albumin to grams per liter, multiply by 10; serum creatinine to micromoles per liter, multiply by 88.4; triglycerides to millimoles per liter, multiply by 0.0113.
Continuous variables were described as medians (IQRs), and binary variables were expressed as numbers (proportions). Qualitative variables were compared using Fisher tests, and binary variables were compared using Kruskal-Wallis tests. Lipoprotein(a) level categories were as follows: normal (<50 mg/dL), high (50 to <134 mg/dL), and very high (≥134 mg/dL).